the arid soils of the balikh basin (syria)

Transcription

THE ARID SOILS
OF THE BALIKH BASIN (SYRIA)
M.A. MULDERS
E R R A T A
THE ARID SOILS OF THE BALIKH BASIN (SYRIA).
M.A. MULDERS, 1969
page 21, line 2 from bottom:
read: 1, 4
page 81, line 1 from top:
read: x
page 103t Fig» 19:
read: phytoliths
page 121, profile 51, 40-100 cm:
read: clay
read: silt loam
page 127, profile 38, 105-150 cm:
read: clay
read: silty clay loam
page 127, profile 42, 4O-6O cm:
read: silt loam
page 138, 16IV, texture:
read: 81,5# sand, 14,4% silt
instead of: 14
instead of: x % K
instead of: pytoliths
instead of: silty clay
instead of: clay loam
instead of: silty loam
instead of: silt loam
instead of: clay loam
instead of: 14,42! sand,
81.3% silt
page 163, add:
A and P values (quantimet),
magnification of thin sections 105x
THE ARID SOILS OF THE BALIKH BASIN (SYEIA).
M.A. MULDERS, 19Ô9
page 18, Table 2:
read: mm
instead of: min
page 80, Fig. 16:
read: kaolinite
instead of: kaolite
page 84, Table 21 :
read: Kaolinite
instead of: Kaolonite
read: at
instead of: a
read: moist
instead of: most
page 109t line 8 from bottom:
read: recognizable
instead of: recognisable
page 115» Fig. 20, legend:
oblique lines : topsoil, 0 - 30 cm
horizontal lines : deeper subsoil, 60 - 100 cm
page 159» line 6 from top:
read: are
instead of: is
5Y
THE ARID SOILS
OF THE BAUKH BASIN (SYRIA)
37?
THE ARID SOILS
OF THE BALIKH BASIN (SYRIA)
PROEFSCHRIFT
TER VERKRIJGING VAN DE GRAAD VAN DOCTOR IN DE
WISKUNDE EN NATUURWETENSCHAPPEN AAN DE RIJKSUNIVERSITEIT TE UTRECHT, OP GEZAG VAN DE
RECTOR MAGNIFICUS, PROF.DR. J. LANJOUW,
VOLGENS BESLUIT VAN DE SENAAT
IN HET OPENBAAR TE VERDEDIGEN OP
MAANDAG 31 MAART 1969
DES NAMIDDAGS TE 2.30 UUR
DOOR
MICHEL ADRIANUS MULDERS
GEBOREN OP 21 AUGUSTUS 1941 TE BERGEN OP ZOOM
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1969
DRUKKERIJ BRONDER-OFFSET N.V.
ROTTERDAM
PROMOTOR: PROF. DR. IR. F. A. VAN BAREN
Aan de nagedachtenis van mijn vader
Aan mijn moeder
Aan mijn vrouw
PREFACE
The Balikh Basin is situated in the Jazirah in the northern part of Syria.
The location of the area and most places referred to in the text are shown on
a locality map (appendix I).
The area under consideration is a part of the region where the Euphrates
Project under direction of the G. O. E. P. (General Organization of the
Euphrates Project) is in operation.
During the years 1965 and 1966, the author was a co-operator of the soil
survey team carrying out a soil suitability mapping.
This volume represents a study of soil forming factors and the genesis of the
soils occurring in the area.
For the treatment of this subject the genetic concept of soil given by
Dokuchaiev in 1870 was of great influence.
Quoting the "Soil classification, a comprehensive system, 7th approximation"
(United States Department of Agriculture, 1960): Soil according to Dokuchaiev
consists of independent natural bodies, each with a unique morphology
resulting from a unique combination of climate, living matter, parent rock
materials, relief and time. The morphology of each soil, as expressed in its
profile reflects the combined effects of the particular set of genetic factors
responsible for its development.
Therefore, the factors of importance for soil formation are dealt with in
detail. These are: climate, geology, morphology, hydrology, mineralogy of
the soil material, flora, fauna and land use.
Also sedimentological processes should be examined in detail before
evaluation of soil forming dynamics. Marbut (quoted by the U.S. soil
classification, see above) wrote in 1913: Important in the classification
of soils is to recognize not only the character of the rock from which the
material has been derived but also the agencies which have acted in the
transportation and deposition of the soil material and the changes which
have taken place since its deposition.
The soils were classified according to the U.S. Soil classification, 7th
Approximation with supplements and a soil map scale 1:50. 000 was
constructed (appendices III and IV).
Morphology and micromorphology were studied being of fundamental
importance for evaluation of soil genetic processes.
ACKNOWLEDGEMENTS
It is a pleasant and proper duty for me to make personal acknowledgements
to all people who were involved in my professional training at the
universities of Groningen and Utrecht. Especially I like to thank Professor
Dr. Ph. H. Kuenen, Professor Dr. M. G. Rutten, Professor Dr. D. J. Doeglas
and Professor Dr. Ir. R.W. van Bemmelen.
In particular I am extremely indebted to Dr. Ir. F. A. Van Baren, professor
of soil science at the State University of Utrecht, who promoted the completion
of this thesis in every way. His criticism and suggestions were of great
value for this study.
The author feels greatly indebted to Dr. J. J. Reynders for his help
and constructive criticism which were of invaluable assistance especially
at the very beginning of work.
Grateful acknowledgement is due to Dr. A. Jongerius who kindly
introduced me to the different methods in soil micromorphology and gave
me all possible help in order to finish this section of the study.
Many thanks are due to Mr. W . L . P . J . Mouthaan for his helpful suggestions
in many problems.
Mrs. T. Baretta-Kuipers determined plants collected in the region and
Drs. J. H. de Gunst examined some chitinous skelets of soil fauna. My thanks
are due to them for helping me in these specialized subjects.
I feel indebted to Dr. H. Bent and Drs. H. Klunder for the introduction
in measuring techniques of X-ray fluorescence and to Mr. H. Vrins BSc for
his invaluable help and constructing advice in X-ray diffraction.
It is a pleasure to express my gratitude to the following for their help
and suggestive criticism: Dr. R.D. Crommelin, Dr. H.J. von M. Harmse,
Dr; J. van Donselaar, Drs. J. Th. de Smidt, Drs. D. Creutzberg,
Drs. P. G. E. F. Augustinus and Mr. P.A. Teunissen BSc.
Acknowledgement is made to a team of soil surveyors working during the
period February 1965 to May 1966 at the Euphrates Project in Syria: Drs. F.
Bos, Drs. A. L.T.M. Commissaris, Drs. P. Petermeyer, Drs. A.F. Sanders,
Drs. J . J . Scholten, Drs. W.J. Vreeken, Drs. S. Wijnhoud, Mr. H. Van Oordt
BSc, Drs. H.G.A. Van Panhuys, Drs. L.A. Van Sleen and especially to Drs.
M.F.W. Zijsvelt for his interesting suggestions and Mr. J. Schoute BSc for
collecting plants throughout the region.
Thanks are due to Mr. L. Fürste, Mr. D. Schreiber, Mr. G. Heintzberger
and Mr. D. Schoonderbeek for their practical assistance in micromorphology,
to Mr. G. van Omme and Mr. F. Henzen for the skill and speed with which
they have prepared the illustrations and maps, and to Mr. A. Reijmerink for
the making of photopraphs.
I consider it a pleasant duty to express my gratitude to Mr. P. van der
Kruk for correcting the English of the manuscript.
The assistance of Mrs. G.H. Visser-v.d. Geest, Mrs. M. MassaroKetting-Olivier, Miss H.J. van Lith, Mr. G. H. de Vries and Mr. G. Kleinveld
of the Institute of Soil science (Utrecht) was greatly appreciated.
A special word of thanks is also due to Mr. J.H.M. Witjes, Mr. H.C.
Van Den Beemt and Mr. J. F. M. Van Tienen for undertaking typing of parts
of the manuscript.
I am greatly obliged to the General Organization of the Euphrates Project
(Damascus), Sir Alexander Gibb & Partners (London) and the Royal Tropical
Institute (Amsterdam) for their valuable help which was indispensable for
the completion of this thesis.
I received a grant from the Ministry of Education (The Netherlands) for
the multiplication of the manuscript which I gratefully accepted.
In conclusion I warmly thank the co-operators of the Euphrates Project
at Raqqa especially Mr. Garo Megerdikhian, Mr. Ibrahim Knetir and
Mr. Abu Bechir who were my delightful company on many desert trips and
made my stay enjoyable with the best memories.
CONTENTS
Page
PREFACE
6
ACKNOWLEDGEMENTS
CHAPTER I
ATMOSPHERIC CLIMATE AND SOIL CLIMATE
15
A. A t m o s p h e r i c
15
climate
1. General
a. A general picture
b. Syria
2. Precipitation
3. Temperature
4. Relative air humidity
5. Evaporation and evapotranspiration
6. Air pressure; wind direction and velocity; sand-dust storms
7. Sky cover and relative duration of sunshine
8. The aridity index of the Martonne and zonality of soils
9. Classification of arid climate
10. Palaeo-climate
B. S o i l
1.
2.
3.
4.
CHAPTER II
climate
Influence of aridity on soil properties
Soil moisture
Soil temperature
Surfacial supply and run-off of water
15
15
16
17
19
20
21
23
24
25
27
28
30
30
31
32
33
GEOLOGY, MORPHOLOGY AND HYDROLOGY
35
A.
Geology
35
1. Tectonical review
2. Stratigraphy and lithology
36
36
40
3. Geological history
B.
Morphology
1. Euphrates terraces and flood plain
42
45
Page
2.
3.
4.
5.
45
45
47
48
48
49
50
50
51
52
a. Flood plain
b. Holocene terrace or lowest terrace
c. Pleistocene terraces
Balikh terraces and flood plain
a. Flood plain
b. Holocene or lowest terrace
c. Upper Pleistocene terrace
Volcano region
Gypsum region
Limestone region
C. H y d r o l o g y
53
1. Hydrology of Syria
2. Hydrology of the Balikh Basin
a. Superficial water
b. Chemical composition and depth of groundwater
c. Storage and use of water by man
CHAPTER III
53
54
54
55
55
MINERALOGY
A. M i n e r a l o g i c a l
(50-500n)
1.
2.
3.
4.
5.
6.
7.
8.
57
analyses
of t h e s a n d
fraction
58
Analytical methods
Problems in connection with the method used
Principles and methods of heavy mineral research
Description of minerals
a. Heavy minerals
b. Light minerals
Mineral provinces and associations
a. Heavy minerals
b. Light minerals
Gypsum, hemihydrate and anhydrite
Weathering of soil minerals
Conclusions
B. M i n e r a l o g i c a l
analyses
of the c l a y
58 '
58
60
61
61
62
63
66
71
73
73
78
f r a c t i o n ( < 2 (j, )
1. Method of analyses
2. Mineralogical composition of the clay fraction
C. M i n e r a l o g i c a l
D. M i n e r a l o g i c a l
minerals.
a n a l y s e s of the s i l t f r a c t i o n
a n a l y s e s o f s o u r c e r o c k s for t h e
79
81
83
soil
1. Origin of the brown loam
2. Origin of clay in the gypsum deposits
3. Mineralogical composition of the Holocene basalt
CHAPTER IV
79
85
85
88
88
E. S u m m a r y
89
SEDIMENTOLOGY OF THE SOIL MATERIAL
91
1.
2.
3.
4.
Sedimentology of the brown loam covering the plateaus
Sedimentology of the sandy gypsum deposits
Sedimentological characteristics of the other soil materials
Some observations about sedimentation during and after a sanddust storm
91
93
94
94
Page
CHAPTER V
FLORA AND FAUNA
96
Basin
96
2. Effect of soil and topography on vegetation
3. Vegetation of the different regions
4. The occurrence of phytoliths
96
98
99
102
A. F l o r a
of t h e E u p h r a t e s - B a l i k h
1. Effect of c l i m a t e on vegetation
B. F a u n a
of t h e E u p h r a t e s - B a l i k h
104
Basin
104
105
1. Vertebrates
2. Soil fauna
CHAPTER VI
LAND USE
106
106
107
107
107
1. History of land use
2. Farming system in the Balikh Basin
a. Valley lands of Euphrates and Balikh
b . Plateau lands
CHAPTER VII
MAPPING METHODS
108
1. General mapping method with aerial photographs
2. Field classification symbols
CHAPTER VIII
SOILS OF THE BALIKH BASIN
A. D e s c r i p t i o n and a n a l y s e s of t h e s o i l
112
profile
1. Description of method of analyses
2. Texture analyses
3. Description and analyses of the soil profile
a. Soil horizon designations
b. Clay minerals as related to average
values of oxides in the clay fraction
B. C l a s s i f i c a t i o n
108
109
of s o i l s
1. Soil classification criteria
2. Description and classification of soils according to the 7th
Approximation with supplements
a. Entisols of the Balikh Basin
a. 1. Fluvents
a. 1.1. Torrifluvents
a. 1.2. Ustifluvents
a. 2. Orthents
a. 2.1. Torriorthents
a. 3. Psamments
a. 3 . 1 . Torripsamments
a. 3.2. Ustipsamments
b. Aridisols of the Balikh Basin
b . l . Orthids
b. 1.1. Calciorthids
b. 1.2. Gypsiorthids
b. 1.3. Camborthids
b. 1.4. Salorthids
112
112
113
116
116
140
140
140
141
142
142
142
144
146
146
146
146
147
147
147
148
154
158
161
Page
3. A comparison with other soil classification systems
4. The soil map
C. M o r p h o l o g y and m i c r o m o r p h o l o g y
the Balikh Basin.
of A r i d i s o l s
161
162
of
163
1. Typic Calciorthids; loam lying over Pleistocene gravel
a. Morphology
b. Micromorphology
c. Organization within the pedological features
2. Typic Calciorthids; Holocene loam of the Balikh
a. Morphology
b. Micromorphology
3. Typic Gypsiorthids
4. Typic Camborthids developed in lapilli mixed with calcareous
loam
CHAPTER IX
SOIL GENESIS IN THE BALIKH BASIN
A. S o i l
forming
processes
formation
as r e l a t e d
181
to t i m e
191
A. A l p h a b e t i c a l l y
editor
arranged
according
t o a u t h o r or
B. A l p h a b e t i c a l l y
arranged
according
to t i t l e
193
CURRICULUM VITAE
APPENDICES
181
182
184
184
184
185
185
186
186
187
188
189
SUMMARY
LITERATURE
170
181
1. Soil physical processes
2. Soil biological processes
3. Soil chemical processes
a. Relatively soluble constituents
1. Calcium carbonate
2. Gypsum
3. Soluble salts (more soluble in cold water than gypsum)
b. Relatively insoluble constituents
1. Silica
2. Sesquioxides
3. Clay minerals
B. S o i l
166
166
167
168
168
168
169
170
I. Locality map of Syria
II. Geo-pedological profiles
III. Soil map of the Balikh Basin; northern part; scale 1:50.000
IV. Soil map of the Balikh Basin; southern part; scale 1:50.000
196
197
STELLINGEN
I
Het verdient aanbeveling voor bodemgenetisch onderzoek een methode te ontwikkelen om "phytolitaria" quantitatief te bepalen.
II
Een micromorphologisch onderzoek is in vele gevallen noodzakelijk voor een
juiste bodemclassificatie.
III
Plasma concentraties zouden een rol moeten spelen in Brewer's classificatie
van plasmic fabrics.
Brewer. R. 1964. Fabric and mineral analysis of soils.
IV
Een K-fabric zal over het algemeen eerst dan continue zijn, indien het zandgehalte van een kalkrijke grond hoog genoeg is. Daarom wordt deze voorwaarde, waaraan een K-horizon volgens Gile, Peterson en Grossman moet voldoen,
onjuist geacht.
Gile, I.H., Peterson, F.F. and Grossman, R.B. 1965. The K-horizon: a master soil horizon
of carbonate accumulation. Soil Sei. Vol. 99. No 2.
Een lithologische kaart zou in bodemkundige rapporten een normale bijdrage
tot de oppervlakte geologie moeten zijn.
VI
De definitie van "loss" behoort niet alleen afhankelijk te zijn van textuur,
maar ook van origine, genese en voorkomen.
Doormaak S. V. D., J.C-A. v. 1945. Onderzoekingen betreffende de lössgfonden van ZuidLimburg. Proefschrift Wageningen.
VII
De verklaring van Kuenen en Perdok betreffende het ontstaan van "desert frosting" is onvolledig.
Kuenen, Ph. H. and Perdok, W.G. 1962. Experimental Abrasion 5. Frosting and defrosting of
quartz grains. The J. of Geol. Vol. 70. No 6.
VIII
Kristalvormen kunnen bij de voorbehandeling ten behoeve van de mineralogische
analyse worden aangetast door toevoeging van 0, 2 N HC1, waardoor bepaalde
diagnostische waarden verloren gaan.
Dit proefschrift, hoofdstuk III.
DC
De uitgestrekte gipsafzettingen in Zuid-West Azië zijn afkomstig van het Mioceen, hebben dientengevolge de Pluviale perioden meegemaakt, en zijn daarom als relatief stabiel te beschouwen.
X
In een bepaalde geologische periode bestaat er een relatie tussen de sedimentaire opbouw van een geosynclinaal en de bodemvorming op een aangrenzend
continent.
Erhart, H. 1956. La genèse des sols en tant que phénomène géologique. Esquisse d'une théorie
géologique et géochimique. Biostasie et Rhexistasie.
XI
Verkeersaanduidingen in verband met werkzaamheden naast de rijbaan dienen
verwijderd te worden als er geen arbeid verricht wordt.
M. A. Mulders
Utrecht, 31 maart 1969
ERRATA
M. A. MULDERS, 1969.
Acknowledgements, page 8, line 1 from
read: Dr.
read: at
page 47, legend fig. 9: .
read: Lowest or Holocene
read: occurred
read: occurrence
bottom:
instead of: Dr;
instead of: a
instead of: Lowest Holocene
instead of: occured
instead of: occurence
read: with
instead of: withe
read: southward
instead of: soutward
instead of: on
read: in
instead of: occurences
read: occurrences
page 77, below Table 19:
add: legend + = Ca; " = Na and/or K
read: Table 25
instead of: Table 25a
read: occurring
instead of: occuring
CHAPTER I
ATMOSPHERIC CLIMATE AND SOIL CLIMATE
A. ATMOSPHERIC CLIMATE
1 . GENERAL
a. A g e n e r a l
picture
Climate is one of the more important factors that govern vegetation
structure, land use and soil type.
Syria with a latitude 32, 3° - 37, 6° and a longitude 35, 3° - 41, 8° in the
northern hemisphere lies in the subtropical high-pressure belt with a pronounced aridity.
The cause of the subtropical high-pressure belt becomes clear on a world
scale in the 3-cell meridional overturning circulation model (Hare 1961).
In the tropics one finds an aequator-ward flow at low levels of the trade wind;
there is an uplift of air at the intertropical front zone, a poleward flow at
some higher level and subsidence near latitude 30 . In mid latitudes there is
a poleward flow at low levels, an aequatorward flow above and also subsidence
near latitude 30°.
The subsidence near this latitude results in dynamical warming, which
lowers the relative humidity and disperses cloud.
Because of a cellular structure of the subtropical high pressure belt,
there are gaps in the arid zone with abundant rainfall.
15
b.
Syria
A narrow strip of low plains and plateaus along the coast of Syria be-
longs climatically to the Mediterranean Basin with warm nearly rainless
summers, humid winters and relatively high air humidity.
Inland Syria is a plateau land with elevations varying from 300 to 1000 m
with dry hot summers and relatively cold winters with rainfall. The rainfall
decreases to the centre of the area of over 500 mm to 100 mm.
The interior does not profit from the Mediterranean climate owing to the
presence of the Libanon and Anti-Libanon ranges parallel to the coast. The
moist air masses reach their condensation level upon orographie uplift on the
windward side of these mountain ranges and lose an important part of their
moisture by precipitation.
When the air moves downslope the absolute vapour pressure is quite low
while the relative humidity is further decreased by the adiabatic warming during subsidence.
Fig. 1. Isohyetal map of Syria.
- Decrease in rainfall from 1000 mm along the coast to 400 mm at Aleppo and 100 mm
at Palmyra.
16
This results in a decrease in rainfall from 1000 mm along the coast to
400 mm at Aleppo and Homs.
To draw direct conclusions about average yearly precipitation from the following climatic figures shown in the tables would be erroneous. The 9-17 years
of recording can be just as well a dry or moist spell. But at least these data
show what can be expected.
2. PRECIPITATION
To the centre of the Syrian area the precipitation decreases. The area
north-west of Palmyra is less arid having a precipitation of 200-300 mm because of the presence of the Amans corridor, a valley perpendicular to the Libanon and Anti-Libanon ranges, giving passage to moist air masses.
Table 1. Average monthly precipitation in mm from Aleppo to Deir ez Zor and from Raqqa to Tal Abyad.
Month
January
February
March
April
May
June
July
August
September
October
November
December
Total
Years of record
Aleppo
65.9
55.1
41.9
36.7
12.9
2.7
0.2
0.9
1.6
12.5
24.9
67.6
323
17
Ma'dan
Jadid
Deir ez
Hurayrah
35.4
22.4
23.8
18.8
33.2
27.4
19.5
20.7
34.2
30.1
24.3
24.2
8.2
0.1
0.0
0.0
2.0
3.7
6.0
1.2
0.0
0.0
0.3
5.7
7.8
0.8
0.0
0.0
0.5
4.9
12.0
20.7
20.5
22.9
11.7
28.1
Abu
147
9
157
9
Raqqa
Hazimah
167
16
Tal
Abyad
Zor
40.7
24.7
26.7
26.3
11.1
5.7
0.0
0.0
2.8
5.0
15.1
24.5
183
10
41.9
23.2
34.2
22.4
7.2
0.7
0.0
0.0
1.4
4.0
9.7
25.0
170
10
57.8
37.1
31.9
33.9
23.3
2.5
0.0
0.0
1.9
13.0
25.2
48.7
275
10
There is an abrupt change in rainfall from Aleppo with a yearly rainfall
of 323 mm to Abu Hurayrah with 147 mm.
This change of humidity is clearly noticeable in vegetation, and in the
colour of the soils, being dark red brown near Aleppo and light yellowish
brown to pale brown in the desert.
The average monthly precipitation at Raqqa deviates only slightly from
that at Deir ez Zor; near Aleppo the rainfall is about twice the rainfall at
Deir ez Zor.
17
From Raqqa to the North, that is to Hazimah and Tal Abyad, there is an
increase in rainfall from 183 mm at Raqqa and 170 mm at Hazimah to 275 mm
at Tal Abyad.
During my fieldwork '65-'66, I had the impression that from Raqqa
northward to Chunayz there was no change in aridity, locally conditions seemed
even more arid (Hazimah). From Chunayz to Ain Isa there was a slight increase
in rainfall, noticeable in the valleys, being green during a great part of the year.
Sometimes heavy night dew occured north of Chunayz. North of Ain Isa rainfall
increases rather abruptly, giving rise to a more green and a little bit higher
grass cover, as compared with the southern area. At all the stations in table
1 the months of June, July, August and September are practically rainless.
Table 2. Precipitation at Raqqa.
Average monthly
precipitation
in min.
January
February
March
April
May
June
July
August
September
October
November
December
Total
Years of Record
40.7
24.7
26.7
26.3
11.1
5.7
0.0
0.0
2.8
5.0
15.1
24.5
183
10
Average
number
of wet days
Maximum fall
in 24 hours
in mm.
9.2
7.8
7.6
7.4
2.8
0.5
0.0
0.0
0.5
2.7
4.3
7.8
37.8
39.3
20.8
37.2
34.0
4.0
0.0
0.0
27.7
37.0
22.0
26.6
10
10
Monthly
precipitation
in mm.
1964
1965
1965
1966
1966
1967
July
August
September
October
November
December
0.0
0.0
0.0
0.0
17.3
42.6
0.0
0.0
0.0
17.7
3.2
10.1
0.0
0.0
27.7
11.5
19.4
29.3
January
February
March
April
May
June
64.8
32.5
29.8
39.3
0.2
0.7
16.4
14.5
12.9
20.1
16.5
0.0
21.0
78.3
53.3
12.6
73.5
0.0
Total
227
111
327
At Raqqa: January is the wettest month of the year with a precipitation
of 40,7 mm.
It is possible that nearly all the rainfall of the month falls in 24 hours '.
The main part of the precipitation comes from cloud bursts. A precipitation of
74 mm/day occurred once in January at Deir ez Zor. Raqqa has an average of
50,6 wet days/year.
Snow does not occur but hail has been observed.
Vernal rain and melting of snow in the upper course of the Euphrates cause
the river to have its highest level at Raqqa in April.
The most striking feature of rainfall in the Syrian desert is its aperiodic
18
nature as is clearly shown by precipitation figures of the years 1964 - 1967 in
table 2.
The year 1965 - 1966 was a dry spell while the preceding and succeeding
years were wetter than normal.
3 . TEMPERATURE
The climate at Raqqa is characterized by a dry hot summer and a cool relatively humid winter.
Table 3. Temperature at Raqqa.
TEMPERATURE AT RAQQA IN °C
Month
January
February
March
April
May
June
July
August
September
October
November
December
Years of record
Average
monthly
temperature
6.6
8.7
12.7
17.5
23.3
28.1
30.0
29.7
25.2
19.7
13.4
8.5
10
Average
monthly
maximum
12.0
14.7
19.3
24.8
31.4
36.5
39.1
38.8
34.2
28.6
21.1
14.4
10
Average
monthly
minimum
1.8
3.4
6.3
10.8
15.1
19.2
21.3
21.0
16.7
11.6
6.6
3.6
10
Range of
monthly absolute
maximum
12.2 to
17.2 to
24.5 to
29.2 to
32. 7 to
40.5 to
41.2 to
41.0 to
36.5 to
31.5 to
24. 7 to
16.2 to
10
18.7
23.6
31.3
35.8
40. 7
43.8
46.5
45.0
41.3
37.5
30. 0
23.0
Range of
monthly absolute
minimum
-7. 6 to
-8.2 to
-3.2 to
-0.4 to
7.8 to
12.3 to
13.5 to
14.3 to
8.6 to
0. 6 to
-7. 8 to
-6.0 to
0. 6
1.7
1.5
7.6
12.3
15.5
20.4
19.9
14.2
9. 6
3. 5
1.0
10
January is the coldest month with an average monthly temperature of
o
6,6 C and an average minimum of 1, 8 C; July is the warmest month with an
average monthly temperature of 30, 0 C and an average maximum of 39,1 C.
The absolute maximum is 46, 5 C in July and the absolute minimum is
- 8, 2 ° c in February.
The hot season starts in May and ends in September.
The maximum average daily amplitude per month mounts 17,8 C in July
and August ; the minimum average daily amplitude per month is 10,2°C in
January.
Frost may occur from November until the end of March; temperature increases rather quickly after March, making the sowing time rather limited.
o
19
30
20
»Î
0T
40
Fig 2. Climatogram of Raqqa.
P=precipitation
T=temperature
M=months of the year.
t
I '0
0
J F M A M J J A S O N D
"*— M—•
A minimum of precipitation during June-September coincides with a maximum of temperature during that time.
4. RELATIVE AIR HUMIDITY
The relative humidity is the ratio between measured vapour pressure and
the maximum vapour pressure possible with given temperature.
Table 4. Percentage of relative humidity and monthly temperature at Raqqa.
Month
January
February
March
April
May
June
July
August
September
October
November
December
Years of Record
Average monthly
temperature
Percentage
relative humidity
6.6
8.7
79
71
59
54
40
33
38
39
42
47
62
75
12.7
17.5
23.3
28.1
30.0
29.7
25.2
19.7
13.4
8.5
13
8
From the definition above it will be clear that it is necessary to compare
the percentages of the relative humidity with the average monthly temperature,
in order to get an idea of the total amount of air humidity.
The relative humidity is on its maximum in January with 79%, and on
its minimum in June with 33%, July and August with 38% and 39%.
It increases rapidly from October with 47% to November with 62%; there
is a decrease from February with 71% to May with 40% . The atmospheric
20
vapour has a function comparable with the function of the glass of a hothouse;
solar radiation can enter a hothouse, but practically no heat radiation can
leave.
With a low air humidity as in deserts and mountain regions, there is
very hot sunshine, cold shadow and great differences between day and night
temperatures.
This phenomenon is clearly marked at Raqqa:
January has a relatively high air humidity and a relatively low average daily
amplitude of temperature, In the period June-July-August there is a low air
humidity, a high maximum temperature and a high average daily amplitude.
5. EVAPORATION AND EVAPOTRANSPIRATION
Table 5. Free water surface evaporation at Raqqa.
Free water surface evaporation in mm.
Month
Average daily
January
February
March
April
1.4
2.2
•4.3
6.3
8.6
May
June
July
August
September
October
November
December
Total
Years of record
•
13.2
14.3
12.2
8.4
5.3
3.0
1.9
Average monthly
43
62
133 .
189
267
396
443
378
252
164
90
59
2 476
% age of total
1.7
2.5
5.4
7.6
10.8
16.0
17.9
15.3
10.2
6.6
3.6
2.4
100
8
Raqqa with a yearly free water surface evaporation of 2476 mm, being
14 times the evapotranspiration, (table 7) has in winter a relatively low and
in summer a very high evaporation .
21
Table 6. Yearly free water surface evaporation from Erzurum to Bagdad.
Place
yearly free water surface
evaporation in mm.
Erzurum
Urfa
Raqqa
Abu Kemal
960
2248
2520
2750
2934
note: Urfa is located in Turkey at the upper course of the Balikh.
Evaporation increases downstream of the Euphrates. It is only twice the
precipitation in Erzurum, the upper course of the Euphrates in Turkey. In the
other places it is about 6 to 20 times the precipitation.
To obtain correct data of evaporation is still a great problem.
Therefore, the more complicated phenomenon of the potential evapotranspiration by a vegetation cover is calculated from a formula.
The formula of Papadakis (1957) was used to calculate the evatranspiration:E+=l,5(eme-ed)
where E is the monthly evapotranspiration in cm, e
the saturation
vapour pressure corresponding to the average temperature of the month and
e the saturation vapour pressure corresponding to dew point. Usually e^ is
equal to the saturation vapour pressure corresponding to the average daily
/ nii.
minimum temperature (e ) •
In this formula, the influence of temperature in increasing saturation
vapour pressure has been taken as a measure of its influence on evapotranspiration; summer figures are sufficiently high in this method, this being the failure
of other methods.
Data of evapotranspi ration of Damascus, Aleppo and Deir ez Zor, calculated by Papadakis in his Climatic tables for the world (1961), are respectively 168, 160 and 199 cm/year.
Only in January at Raqqa, is rainfall greater than evapotranspiration, the
difference or leaching rainfall being 2 cm (table 7).
The dry season, according to Papadakis during months in which rainfall,
plus the water stored in soil from previous rains cover less than half of the
evapotranspiration, extends for Raqqa fx*om April until November.
22
Table 7. Evapotranspiration in cm at Raqqa; E = 1, 5 (e
Month
January
February
March
April
May
June
July
August
September
October
November
December
Total
-e
)
Evapotranspiration
2
4
5
10
19
28
30
30
21
15
7
3
174
Penman has made use of evaporation data in calculating the potential
evapotranspiration. Formula of Penman: E = C . E Q ; E Q is the evaporation of
a free water surface and c is a correction factor depending on the nature of
the crops and on the degree inwhichthe soil is covered by them.
For grasslands c = 0,65 and the yearly potential evapotranspiration at
Raqqa is 1609,4 mm. A yearly rainfall of 183 mm, derived from winter and
early spring rains, can support the natural grass vegetation only for a short
period.
6. AIR PRESSURE; WIND DIRECTION AND VELOCITY; SAND-DUST STORMS
Rain-bringing depressions move in easterly direction during winter losing
a great part of their moisture on the Libanon and Anti-Libanon ranges, and
giving some rain in Syria. Western direction of the winds is much less pronounced in winter than in summer, eastern winds can occur also.
The differences in air pressure are greater in summer than in winter,
as a consequence the wind velocities are higher and there are more sand-dust
storms in summer.
The wind velocities are high enough to give rise to a great number of
sand-dust storms (table 8) . The maximum wind velocity measured at Raqqa
is 20m/s'ec.
23
Table 8. Wind velocity and sand-dust storms at Raqqa.
Month
Monthly average
number of days
with sand-dust
storms
Average monthly
wind velocity
in m/sec.
January
February
March
April
May
June
July
August
September
October
November
December
Years of record
0.7
1.1
2.1
1.9
2.4
2.8
2.9
0.7
1.1
1.2
1.2
0.4
9
2.8
2.9
3.4
3.3
3.7
4.9
6.0
4.8
3.6
2.2
2.0
2.4
7
When the wind velocity increases in March, also the number of sand-dust
storms is increasing. There may be a relation to the start of agricultural
activities at that time which results in a destruction of the soil surface.
The duration of these sand-dust storms is 4-10 hours up to a maximum
of 1-2 days. Generally the visibility is less than 1000m. Locally in the centre
of the storm this can be less than 25m, as happened to me near Hazimah.
In summer whirl winds occur daily; their diameter varies from a few
meters up to more than 100 meters. These whirl winds arise from the local
differences in the degree of heat absorption and heat radiation of the soil
surface; the ascending hot air takes some soil particles with it in a spiral-like
upward movement. As energy is depleted at a certain height the dust and sand
disperse and sink after some time. However, even with calm weather, some
of it stays in the air.
7. SKY COVER AND RELATIVE DURATION OF SUNSHINE
The degree of sky cover is practically zero in summer, as a consequence
there is a maximum of sunshine.
The degree of sky cover is increasing towards the winter to about 50%
24
(4 octas). There is relatively much sunshine in winter due to the fact that cloudiness occurs especially in the night.
Table 9. Duration of sunshine at Raqqa.
Month
January
February
March
April
May
June
July
August
September
October
November
December
Total
Years of Record
Average
total hours
of actual
sunshine
at Raqqa
157.8
172.9
237.4
257.8
322.7
361.0
382.6
366.1
332.7
276.2
214.4
158.0
Average
percentage
of sunshine
at Raqqa
54
60
68
70
81
92
96
93
92
85
74
55
3 240
9
9
8. THE ARIDITY INDEX OF THE MARTONNE AND ZONALITY OF SOILS.
Rainfall/temperature indices are intended to summarize features of the
macro-climate. They are gross values which do not entirely reflect microclimate and run-off processes. However, general processes of soil formation
can be deduced.
The Martonne suggested the following index of aridity:
P/10+T, where P represents the annual precipitation in mms and T the annual
temperature in °C.
This index can be used in summarizing the climatical, hydrological and
soil formative conditions.
A correlation between the index of the Martonne and the soil type will be
possible in the Near East since climate has not changed very much after the
end of the Pleistocene.
The curves of equivalence of aridity index and the main soil types of
Syria are shown in fig. 3.
25
300km
Fig 3. Aridity index of the Martonne (adapted from Abd-al-Al) and zonality of Syrian soils (adapted
from W.J. van Liere).
legend of soils:
a. Red Mediterranean soil.
b. Grumusol.
c. Arid brown soil (Cinnamonic ace. van Liere)
d. Gypsiferous soil.
e. Grey desert soil.
a.
b.
c.
d.
26
Main soil types of Syria:
Red Mediterranean soils: Dominant colour red; clay loam and loam; montmorillonitic; pH 7-8; little horizonation; some clay movement.
Grumusol: Dominant colour dark red, brown, dark brown and black; montmoriilonitic ; pH 8-8,5; no horizonation; self-mulching.
Arid brown soil: Dominant colour reddish yellowish brown; illite, palygorskite and montmorillonite ; loam and clay loam; highly calcareous; pH 8-9;
little horizonation; calcic horizon; unstable structure.
Gypsiferous soils: Dominant colour yellowish-orange brown to white powdery;
pH 8,5; often gypsum crusts.
e. Grey desert soils: Dominant colour brown-grey and grey; highly calcareous
loam.
The curves of equivalence of aridity index roughly coincide with the major
soil types. The 25 index curve corresponds to the boundary between Red Mediterranean soil and Grumusol.
The boundary between Grumusol and Arid brown soil is approximately
the 10-13 index curve.
Arid brown soils are found from the 10-13 index curve up to approximately the 5 index curve. The 5 index curve delimits a zone with soils without
any profile development.
There are three main zonal types : humid red soils, arid to semiarid brown
soils, and arid grey soils in areas with a precipitation being less than 100 mm.
The content of iron-oxides is decreasing with increasing aridity.
The gypsiferous soils do not correspond to zones with equivalence of aridity index, the climatic habitus being overshadowed by soil characteristics inherent from the gypsiferous parent material.
9. CLASSIFICATION OF ARIP CLIMATE
There is no generally accepted definition for aridity, but one of the simplest classifications states that 250 mm rainfall is the dividing line between
arid and semiarid, and 500 mm between semiarid and humid.
These limits of rainfall are suitable for the Mediterranean area, however,
for tropical margins of the deserts a greater amount of rainfall is required to
make an area humid.
After Dixey (1962) arid regions can be divided into:
- semiarid
250-300 mm to 500 mm precipitation
- arid
50 to 300 mm precipitation
- extremely arid less than 50 mm precipitation
In the semiarid regions water is deficient for normal crop growth,but
they have a great significance as natural grass-lands.
As for the Balikh Basin:
Raqqa and Hazimah have an arid climate ; Tal Abyad on the Turkish border
with a precipitation of 278 mm has an arid to semi-arid climate.
After Bagnouls and Gausseii (1957) a month is dry if precipitation in mm
27
is less than twice the temperature in °C.
This means at Raqqa that April until November is the dry period.
Raqqa has to be classified according to theseauthorsas a Xerothermo-mediterranean climate, having eight dry months a year.
However, distribution and amount of rainfall together with maximum and
minimum temperatures are of great significance to the distribution of crops and
vegetation. Using humidity regime and temperature regime Papadakis (1961)
classified Deir ez Zor and Damascus as a frosty hot subtropical desert with the
addition more grassy than usual in desert; Raqqa belongs to the same class.
A desert more grassy than usual due to the mediterranean influence in
winter, while the summer has a continental influence.
When using vegetational criteria only, the degree of vegetation cover, the
possibility of dry farming and grazing result in a classification as semi-desert.
10.
PALAEO-CLIMATE
Hull and Blanckenhorn discovered that Pleistocene pluvial periods a lower
latitudes were directly related to the Pleistocene glacial periods in middle and
higher latitudes (Butzer 1961), During the greater part of the Pleistocene the
climate at lower latitudes, in North-Africa and the Levant, was as arid as it
is today, the pluvials were only temporary features.
After K.W. Butzer: full aridity set in at least 8000 years before the end
of the last glaciation.
Valley systems are evidence of an intensive erosion and greater humidity
during the Pleistocene, Their incision took place during the Middle and Upper
Pleistocene uplift.
Terra Rossa formation took place during the Riss-Würm interglacial
period in the Libanon ranges and in Turkey.
The greater part of the Holocene was arid or even more arid than today.
In the Atlantic period there was a markedly greater humidity and rainfall, making
possible a more exuberant fauna and flora.
There was a greater aridity during Preboreal and Subboreal; the early historical desiccation shortly before 2000 B.C. was quite severe, as conditions
were extremely arid. The reversal from an extremely arid climate in Subboreal time to the arid climate of today took place about midway of the last
28
Table 10. Pleistocene and Holocene climate of the arid zone at lower latitudes (North-Africa and the
Levantine Area) (adapted from K.W. Butzer 1961.).
Geological time
Pleistocene
Climate
Lower Pleistocene
600. 000 years B.C.
Middle Pleistocene
475.000 years B.C.
Upper Pleistocene
100. 000 years B.C.
Holocene
Preboreal
8500-6800 B.C.
Boreal
6800-5600 B.C.
Atlantic
5600-2500 B.C.
Subboreal
2500-8/500 B.C.
Subatlantic
After 500 B.C.
Pluvial (GUnz glacial)
Interpluvial (Günz-Mindel interglacial)
Pluvial (Mindel glacial)
Major Interpluvial (Mindel-Riss interglacial)
Pluvial (Riss glacial)
Interpluvial (Early Riss-WUrm interglacial)
Pluvial (Late Riss-WUrm interglacial)
Pluvial (Early Wurm glacial)
Postpluvial (Late WUrm glacial)
Extremely arid
Arid
Moist, warmer
Extremely arid
Arid, slightly moister
millenium B.C. Only short term fluctuations occurred since that time,never exceeding the order of a few hundred years.
Roman ruins near Raqqa e.g. Al Rasafah, Halabia and Zalabia, gave the
impression that climatic conditions in Roman time did not differ much from today; this applies also to Palmyra and Dura Eropos.
The abandonment of wide areas of the Levant during the sixth century A.D.
was not due to a greater aridity, but was a result of increasing economic deterioriation and political instability in the disintegrating Roman empire.
In the Subatlantic arid climate short term fluctuations occurred with more
or less markedly dry and moist spells. These climatic fluctuations, giving only
a small fluctuation of temperature and rainfall, had not much influence on soil
development.
The period since 1900 A.D. can be seen as a dry spell.
To long term droughts of a few centuries man can adapt himself without
special hardship. However, short term droughts of a few years duration can
bring swift disaster to agricultural communities.
Droughts of economic importance plagued the Levantine area in the 1920s
29
and 1930 s. The great variation in rainfall means a special problem for dry
farming and stock raising, as did the low rainfall during the winter of 1966.
Therefore, it is necessary to maintain a balanced view of minor climatic
fluctuations of a few years duration.
A moist period during the Atlanticum explains soil characteristics associated with wetting at greater depth in soils on the plateaus as are mottling and
gypsic horizons. The soil profile will have been wetted more deeply in the Atlanticum while a thoroughly wetting in recent times on the plateau lands is r e stricted to the topsoil and subsoil.
B. SOIL CLIMATE.
The soil climate is characterized by a "non flushing regime" (Rode 1961),
that has:
a. A groundwater table which lies too deep under the surface to have influence
on soil forming processes.
b. Supply of water by rainfall and to a lesser degree by night dew.
c. Drain of water by evaporation and transpiration. High evaporation results in
an upward movement of soil water.
These processes determine the properties of the soil profile.
The results of climatic action on soil will be discussed below.
1. INFLUENCE OF ARIDITY ON SOIL PROPERTIES
The effective rainfall is about half of the total rainfall, the other half falling
in too small quantities and/or evaporating from the leaves or directly from the
soil surface. In winter there is a slight chemical weathering due to the presence
of soil moisture.
Chemical weathering is on its maximum in the early spring owing to a
maximum of soil moisture, higher temperatures and as a consequence relatively
high biological activity. In summer all weathering by the solvent action of water
ceases as a result of the scarcity of water. The intense insolation during summer
destroys most of the organic matter formed in winter in the upper soil layer.
The slight chemical weathering results in corrosion of sodium and/or calcium containing minerals. Calcium carbonate is precipitateu in subsoil and
deeper subsoil but sodium moves with the upward moving soil water to the surface
and can lead to accumulation after the evaporation of water.
30
If chloride ions are abundant also calcium and magnesium can become accumulated in the topsoil. These salts being hygroscopic can attract water from night
dew and appear as dark coloured patches on the soil surface in the morning, the
so called sabakh phenomena.
Because leaching is nil calcium and/or sodium are the dominant cations
and the pH is alkaline.
2. SOIL MOISTURE
The percentage of moisture in loamy soil in relation to soil depth is shown
in fig. 4.
In dry brown loam the percentage of moisture in the deeper subsoil at 1 m
is about 10% and there is an increase to about 15% below this depth.
Irrigated loamy soil has a moisture content at 2 m of about 20% even if
irrigation has not been practiced for years. However, the upper 100 cm of such
soil is below wilting point and cannot support plantgrowth (wilting point for
loamy soils will be about 15-18% for most plants). In addition the upper 40 cm
are extremely dry.
depth
in cm
200
300
0
10
20
% moisture—•
Fig. 4. Percentage of moisture in relation to soil depth as determined during August 1965.
legend: T=non-irrigated brown loam; Raqqa terrace; land use cereals.
B= since 2 years non-irrigated clay loam-, Balikh; land use cereals.
1= irrigated brown loam; Hamret terrace (profile 17); land use cotton; 1= 4 days after irrigation ; 2= 11 days after irrigation.
31
The curves 1 and 2 of fig. 4 give an idea about water consumption by plants
and evaporation from the soil surface. The intervals of irrigation gifts on this
field were estimated to be 16 days.
Cracks are formed upon drying after irrigation to a depth of 10-17 cm.
These large interconnected cracks form an irregular pattern in which
other systems of smaller and shallower cracks develop.
The soils are generally far below field capacity, which is 25-30% moisture for brown terrace loam, below the zone of wetting at about 2 - 3 m nonirrigated soils are dry.
The groundwater table is generally found on the plateau lands at a depth
of 20-30 m.
3. SOIL TEMPERATURE
There is very little reflection or absorption of short wave radiation of
the sun by clouds in summer due to a low degree of sky cover.
Some reduction occurs by dust in the air during and after dust storms.
However, the depletion is low and the result is a high amount of solar
radiation.
This will heat the air and the soil owing to the absence of sufficient water
in the topsoil.
0
Table 11. Monthly soil temperature at Raqqa in C.
Month
January
February
March
April
May
June
July
August
September
October
November
December
Years of Record
32
Average monthly temperature
of the soil at a depth of
10 cm.
20 cm.
8.0
8.8
10.3
14.2
20.4
27.5
33.7
35.6
35.4
30.2
23.0
16.0
10.6
10.8
14.5
20.5
27.3
33.3
35.4
35.4
31.1
24.0
17.2
11.4
7
50 cm.
10.9
11.8
15.3
20.2
26.2
32.1
34.4
34.7
31.5
25.9
19.7
14.0
Range of extreme temperatures
of the soil at a depth of 10 cm.
100 cm.
Maximum
Minimum
14.6
13.9
15.6
19.1
23.7
29.0
31.3
32.4
30.9
27.4
22.9
18.0
8.4 to 14. 8
-0.6 to 8.9
2.0 to 11.6
1.8 to 13.8
10.4 to 19.0
16.7 to 24.9
22. 8 to 32. 0
25.3 to 34.6
24. 5 to 34. 5
19. 9 to 29. 9
8. 6 to 20. 8
3.3 to 15.4
2.3 to 10.3
11.7
17.6
21.3
30.3
37.5
39.4
29.9
33.2
24.4
15.9
12.0
to 17.5
to 23.4
to 30.4
to 39.1
to 42. 0
to 41.6
to 41. 2
to 37. 8
to 31.9
to 26. 4
to 16.9
The average monthly soil temperature in the topsoil fluctuates at Raqqa
between 8 C in January and 35,6 C in July. Extreme minimum and maximum
temperatures measured are respectively - 0,6 and 42°C.
The yearly amplitude is decreasing downwards in the soil profile.
At 200 cm depth soil temperature is about 27°C in August.
Generally temperature is increasing at a depth of 5 cm from 10 o'clock
to 13 o'clock only about 3-4°C, at a depth of 50 cm 0, 5°C and at 100 cm there
is no increase.
Differences between day and night temperatures are larger.
Prolonged selection of drought tolerant plant species in the hot arid climate
resulted in a sparse vegetation whose capacity to resist water loss is well marked.
A high albedo or reflection intensity is an ecologically desirable thing in
reducing the evaporation of water and fluctuation of soil temperature.
The vegetation is light in colour and appears pale grey to light brownish
in the full sun, resulting in a high albedo.
The albedo is related to the soil type. It is low in the dark coloured volcanic deposits and irrigated soils, and high in the light-coloured gypsum deposits
and soils with salt efflorescences.
In the terrace loams it is increased by a lighter coloured platy surface
layer and the occurrence of white fungi.
Water is a better conductor of heat than air, more of the heat will be used
to heat deeper soil layers and in evaporation (80 - 90%), less will be used in
heating the air. Therefore, soil temperature of irrigated soils will be lower than
that of non-irrigated soils and the difference in temperature between topsoil and
deeper subsoil will be smaller. Maximum temperatures of 42°C will not be
reached in irrigated soil (such temperatures would be unfavourable for the metabolism of cottonroots).
4. SURFACIAL SUPPLY AND RUN-OFF OF WATER
During the winter occasional violent rain storms of a cloud burst type
loosen the surface soil and transport it down the slopes into the wadis. The
surface has become somewhat resistent against such erosion by the formation
of a platy surface layer.
The surfacial supply of water is dependent on the permeability of the surface
soil layer.
33
The intake rate of the topsoil (table 12) has been measured with the aid
of steel cylinders wii'i diameter 25 cm and height 35 cm. The cylinders were
driven 15 cm into the soil surface. Water was made to penetrate around the
cylinder to prevent lateral drain of water at the foot of the cylinder by soil
suction. Measurement of intake rate should be done with a constant head. In the
case of loamy soils, this was obtained in practice: by refilling the cylinder every
hour.
Table 12. Average intake rate in cm/h of the topsoil.
Region
texture
intake cm/h
Volcano
Ham ret
Balikh
Euphrates
lapilli loam
loam
clay loam
loamy sand
silty loam
clay loam
5
6
2
9,5
6
0,9
Intake rate depends on texture, water content, chemical composition of the
saturation extract and the packing of soil aggregates.
Lapilli loam has a lower intake rate due to a higher sodium content
resulting in dispersion of clay upon wetting and consequent obstructing of the
voids.
Run-off will be low in the Terrace loam soils, but will be more significant
in the clay loams of Balikh and Euphrates, these having a low intake rate.
34
C H A P T E R II
GEOLOGY, MORPHOLOGY AND HYDROLOGY
A. G e o l o g y :
Geology of Syria is discussed by Blanckenhorn (1915).
A review is given below.
Conditions in the Syrian and Arabian area were terrestrial during the
Palaeozoicum and the first half of the Mesozoicum.
The area was linked with the Sahara until the Upper-Tertiair y when the
rift valley of the Red Sea formed.
The Syrian area is bounded to the north by the folded area of the Tauros
and Kurdistan mountains.
The morphological character of the Syrian-Arabian area as well as the
Sahara is determined by faults.
Where lava was present at greater depths it has been extruded along the fault
lines; also efflata have been formed.
1.
2.
3.
4.
5.
Syria can be divided in five stratigraphie al units:
The Libanon ranges along the coast built up of Jurassic and Cretaceous limestones .
The Anti-Libanon and Palmyra mountains built up of Cretaceous limestones.
South-east Syria with Mesozoic sediments.
The Tertiairy of inland Syria with Miocene lagoonal sediments in the Jazirah,
surrounded by Palaeogene sediments.
Basalt flows south of Damascus, where they cover a vaste area, and in the
vicinity of Horns, Aleppo and Raqqa having a limited extension.
35
The area under consideration is located in the Tertiairy of inland Syria.
1. TECTONICAL REVIEW
The Balikh area is located in the marginal part of the Arabian platform
which is mobile and belongs to the African platform. The stable part of the
Arabian platform has a shallow Precambrian basement and gently dipping sedimentary cover. The mobile part is characterized by linear and block type folding in the sedimentary cover and the basement is varying in age and depth. Some
tectonical structures of the area are given in fig. 5. Their influence on morphology is discussed in section B.
The Balikh Basin has been lifted up in the north while descending tectonical movements have prevailed in the south.
Therefore, the region can be divided in two tectonical units as described
below.
The Tuwal al Aba anticlinal uplift extends from east to west and is composed of Lower to Middle Miocene strata. To the west it is bordered by a fault.
The Miocene Euphrates depression extends south of this uplift.
The platform cover is built up of Miocene strata. Neogene-Quarternary
depressions have developed in this depression and are in filled with Pliocene
and Quarternary strata. These depressions are separated by faults.
2. STRATIGRAPHY AND LITHOLOGY
Apart from a limited area with basalt, the Balikh Basin is underlain by a
bedded sequence of Neogene sedimentary rocks and alluvial, proluvial or aeolic
Quarternary deposits.
The Miocene is presented by lagoonal sediments which belong mainly to
the Fars series. Litho logically these series may be divided into the Lower and
Upper Fars, the former outcropping in the region more extensively. The lower
Fars rocks are an interbedded sequence of marls, gypsum, clays, silty sandstones and limestones. Marl and gypsum are the predominant rock types.
The dominant rock type of the Upper Fars is sandstone with interbedded
siltstone.
The Pliocene rocks are of the terrestrial type, being lacustrine, alluvial
or proluvial. The Pliocene rests with a sharp unconformity on the underlying
36
/o
Fig.5. Tectonic map of the Balikh Basin ( adapted from Technoexport 1963 ) .
Legend : 1 = Jarablus anticlinal uplift; 2 = Tuwal al Aba anticlinal uplift; 3 = Area with northwestern
trend of folds; 4 = Slope of the nortwestem Syrian uplift; 5 = Euphrates Miocene depression;
6 = Turkmaniyah Oligocène-Quarternary trough; 7 = Basalt; 8 = Anticline; 9 = Syncline;
10 = Anticline supposed according tot gravimetric data; 11 = Fault expressed in landscape;
12 = Contours of the Pliocene depressions.
lagoonal Miocene sediments. The dominant rock types are conglomerates, sandstones, clay, marls and limestones.
The Pleistocene has been divided into the Lower, Middle and Upper Pleistocene.
The different pluvial and interpluvial periods of these are shown in table 10.
The Lower Pleistocene is represented by alluvial pebbles and proluvial
gypsum-bearing deposits. The alluvium comprises the alluvial cover of the IVth
Euphrates terrace (thickness 10 - 15 m) built up of gravel, and the old proluvial conglomerates and carbonate crust lying directly on an older Quarternary
37
Fig. 6. Geological Map of the Balikh Basin ( adapted from Technoexport Report 1963 ).
Legend : al Q Quarternary alluvial: pebbles, conglomerates, sands, sandy loams, loams.
b Q Upper Pleistocene-Holocene basalts.
P
Pliocene : sands, sandstones, pebbles, conglomerates, marls.
M
Lower-Middle Miocene : gypsum, limestones, marls, sandstones.
denudation surface (thickness respectively 6m and 2m).
Proluvial gypsum-bearing deposits accumulated as a result from local
slight uplifting in the Tuwal al Aba swell.
The Middle Pleistocene comprises the m Euphrates terrace (thickness
10 - 20m) represented by coarse gravel and poorly cemented conglomerates.
The pebbles belong lithologically to the Turkish Complex with pebbles of
38
granitoid, shale, quartzite. quartz (1/3 of total), basic effusives, limestones
and siliceous rocks.
The Upper Pleistocene is represented by alluvial deposits and volcanic effusiva. Thealluvium comprises the II Euphrates terrace, preserved on the
left side of the Euphrates valley slope and in the Balikh mouth (thickness 12-20
m).
The pebbles belong lithologie ally to the Turkish complex. The II Balikh
terrace belongs also to the Upper Pleistocene. It is exposed in the north of the
region and comprises gravel and oblique laminated breccious limestone material
mixed with loam (thickness 3 - 7m).
The Upper Pleistocene volcanism is represented by the Mankhar volcanoes
east of Raqqa. The Mankhar Gharbi volcano is situated in the area.
The volcano is of the Somma-Vesuvius type with two sequential stages of
eruption, separated by a long quiet period. The first stage has an explosion nature and no lava formed. The somma formed as an eruption ash pile, entirely
made of thin laminated fine pyroclastic products, which consist of grey volcanic sand, ash, lapilli and bombs with a diameter of 10-30 cm.
In the second stage the Vesuvius piles were formed inside the crater, and
lava flows were acting. The piles are built up of lapilli with lava intrusions.
Locally aeolic loam has been mixed with the lapilli.
The geological age of the Mankhar volcanoes is defined by their piercing
the gravel layers of the II
Euphrates terrace. The pyroclastic material r e sulting from explosive igneous activity of the first stage covers the surface of
the m and n n Euphrates terrace while it is lacking on the I s terrace. Hence
the somma arose after the formation of the U n terrace.
The lava flows cover the fine pyroclastic products. The Vesuvius piles
and related lava flows of the second stage correspond in age to the Holocene
period.
The Holocene is represented by alluvial and aeolic deposits.
The following deposits belong to this period:
a. The 1st Euphrates terrace represented by sands, clays, gravels and conglomerates (thickness 27 - 35 m; height 2 - 3 m above floodplain).
b. The floodplain of the Euphrates represented by sandy loams, sand, gravel
and pebbles.
c. The I s Balikh terrace built up of brown loams, mixed with some gravel and
pebbles of limestone and flints (tickness 5 - 10 m). There are intercalations
of sandy loams or clay layers.
39
d. The floodplain of the Balikh with brown clays.
e. Aeolic loam covering the Euphrates terraces, the proluvial and aeolic gypsum
deposits and the fine pyroclastic products of the volcano Mankhar Gharbi.
f. Aeolic gypsum deposits covering the proluvial gypsum deposits.
g. Proluvial gypsum accumulations on the Quarternary terraces of the Euphrates.
h. Colluvial calcareous and/or gypsifereous grey loams in the valleys of the e s carpments with exposures of Miocene rock,
i. Lava flows of the Mankhar Gharbi volcano.
Sedimentological characteristics and origin of some of these deposits are
dealt with in chapter IV.
Fig. ' . Mankhar Gharbi volcano.
3. GEOLOGICAL HISTORY
The geologicaL history can be subdivided in three qualitatively different
40
stages :
a. Depositing of Upper Cretaceous and Palaeogene carbonate rocks in a basin
of normal salinity and open marine conditions (Thetys). Sedimentation during
the larger part of the Palaeogene occurred under conditions of smooth tectonic movements under which descending ones were predominant. Upward
tectonic movements are marked by the occurrence of wash outs and
conglomerates.
The uniform sagging kept on until the end of the Oligocène, noticeable in the
uniform massive limy sediments.
b. During the Aquitanian a rising tectonic movement resulted in a stop to accumulation of the Oligocène deposits. In the Helvetian there was sedimentation
of organogeneous limestone and other offshore terrestrial sediments in shallow water.
In the northern part of the North-West Syrian Uplift (Hama-Aleppo area) sedimentation kept on with the result that the uplift enlarged, and for the first
time the Mediterranean and Mesopotamian basins became isolated from each
other, only connected by a strait north of this uplift (north of Jarablus).
During several short periods the above mentioned basins were separated; this
is reflected in the lithology of the lagoonal sediments. A poor connection of
the basins or disconnection gave rise to deposition of gypsum; on the other
hand a connection resulted in deposition of limy sediments.
During the Tortonian the rising of the Tuwal al Aba area and the formation
of the Euphrates depression took place.
c. During the end of the Miocene there was a rising tectonic movement, giving
a transition to a continental stage. The beginning of the Pliocene was a quiet
period with local sagging and the formation of small and shallow inland basins.
The rising kept on during Quarternary periods giving rise to erosion of the
older Miocene and Oligocène strata and formation of Pleistocene terraces.
The valley of the Balikh was formed at the start of the Upper Pleistocene.
The Balikh at that time flowed to the west, north of Hazimah, and via the
Wadi al Fayd to the Euphrates valley. At the end of the Upper Pleistocene, thecourse of the river changed to its recent stage due to tectonic movements.
At this time the Mankhar volcanoes were in the first stage of their development.
This volcanism can be seen as a continuation of basalt extrusions along the
Main Euphrates fault stretching from the north-west to the south-east and in the
area buried under Quarternary deposits.
41
During the Holocene the Euphrates changed from a rapid river with much
gravel deposition into a meandering river with sedimentation of more fine-textured material; the 1st Euphrates terrace was formed at that time.
In recent times the floodplain and riverbedding were formed due to a d e gradation of the Euphrates on account of increased erosion in its own riverbed.
B. M o r p h o l o g y
The oldest component of the topography is the Syrian Plateau, a Lower
Pleistocene denudation plain, formed on the Upper Eocene to Pliocene sediments.
The surfaces of the alluvial and the denudation plain gradually merge into
each other. Distortion of the plain topography was caused by subsequent uplifts
providing downcutting of the Euphrates valley.
The areas of development of the Middle and Upper Pleistocene erosion
types of topography generally coincide and show that there was a relative tectonic stability.
The relief forms can largely be considered to be inherited from the Pleistocene, since Holocene climate was practically as arid as it is today.
Relief is a function of rock type, tectonical processes, climate and time.
The relation between the faultsystem and the course of :.ivers in part of
the Jazirah is indicated in fig. 8.
The south-southwest—north-northeast and southeast-northwest direction
of the faultsystem has determined the course of the rivers.
The main Euphrates fault is accompanied by basalt effusiva.of Zalabyah
and the Mankhar volcanoes. North-west of Zalabyah this fault is buried under'
Quarternary deposits. The escarpment with Miocene sediments near Hazimah
marks the continuation of this fault.
The Wadi alFayd is also accompanied by an escarpment with exposed Miocene.
The Euphrates first following some fault lines continues its course downslope the Northwest Syrian uplift and near Raqqa along a secondary fault of the
main Euphrates fault which is marked by a steep escarpment with a maximum
slope of 110 m per km.
The Syrian plateau is lying here some 100 m above the Euphrates Lowest
terrace.
42
'-C'-H basalt
F i g . 8 . Fault system and course.of rivers in part of the Jazirah.
Indicated are the course of the Euphrates and tributaries, main faults ( - - ) and basalt.
Pleistocene terraces are preserved on the left side of the Euphrates valley.
The Middle Pleistocene terrace T3 is lacking in the Raqqa terrace region
and intensively eroded and reworked in the Hamret terrace region (fig. 9).
The Raqqa terrace region is part of the "Island", a triangular area, formed
by incision of the Balikh and the Euphrates.
The Balikh can be divided in its old course, the Wadi al Fayd, and in its
recent course, the Nahr Balikh.
During the Upper Pleistocene the Balikh continued its course to the Euphrates valley along the Wadi al Fayd fault.
At the end of the Upper Pleistocene the river changed its course near Hazimah to the eastdue to tectonical instability alongthe Main Euphrates fault. This
43
instability can be related to the activity of the Mankhar volcanoes which came
into being at that time.
The "Island" was rising, as is proved by the escarpments along the main
Euphrates and Wadi al Fayd faults. The higher situated terrains north of the
"Island" drained via the Nahr Balikh and Wadi al Fayd leaving the lower Pleistocene terrace on the "Island" almost without eroding. This terrace served as
a collection reservoir fer drainage water.
The drainage water eroded on its way to the Euphrates most of the Middle
Pleistocene terrace. This terrace is preserved to the east and west of the "Island".
East of the "Island'Mn the Hamret terrace region where the terraces were
not protected against drainage of higher terrains, the Lower and Middle Pleistocene gravel is intensively reworked and deposited on the
Upper Pleistocene .
Rising tectonic movements resulted in deep incision of the Upper Pleistocene terrace.
During the Holocene the Euphrates changed from a rapid river with gravel
deposition into a meandering river with deposition of finer textured material.
In recent times the Euphrates degraded to a lower level due to increased
spring floods and decreased supply of debris. So the flood plain formed.
The banks and plateaus adjacent to the Euphrates river are very rich in
flint tools. Van Liere (1960-1961) dated them to be Upper Paleolithic to Neolithic or probably later. The age of the floodplain is dated with the aid of antiquities .
The result of climatic action on rock is dependent on consistence and mineralogical composition of rock.
Therefore, as a first approach to morphological characteristics of the r e gion, the relief of the different rock types can be studied.
The characteristics of the various landscapes in the Balikh Basin are given below. The location is shown on the morphological map fig. 9.
Topographic features of the terrace region are indicated in this map. Profiles are constructed giving details about relief, thickness of soil cover and
soil horizons, They are given in appendix II.
44
1. EUPHRATES TERRACES AND FLOOD PLAIN
a. F l o o d
plain.
The elevation upstream is 240 m and downstream 230 m, its slope gradient is 36 cm per km.
Terrace meanders formed, cutting downvalley owing to an accelerating
force derived from the general slope.
The most characteristic feature of the flood plain is the great number of
shallow channels the so called "flood plain scour routes" only used during
spring floods.
Dunes of a few meters high have developed in sandy deposits.
Riverbed and flood plain have a Post-Medieval age (v.Liere 1960-1961).
b. H o l o c e n e t e r r a c e o r l o w e s t t e r r a c e (T^), lying approximately
3-7 m above the flood plain and being 3,5 to 7 km wide.
Its topography is rather flat.
Occasionally dunes of a few meters high developed on the sandy ridges of
point bars.
Drainage of the high terraces takes place by relatively deep gullies (3-6 m)
which are dry in summer and have their outlet at that time a few meters above
the waterlevel. In winter and spring time when the gullies often contain water,
the Euphrates river level is a few meters higher than in summer (a maximum
in spring time of 3m).
The Balikh continues its course through the terrace and discharges
into the flood plain at two places. South of Hamret Naser the Balikh follows an
old meander of the Euphrates.
The slope gradient of the lowest terrace is equivalent to that of the flood
plain and terrace meanders cutting down valley are found.
These terrace meanders are indicated on the morphological map where
the difference in elevation was 2-3 m.
Point bars are typical for the Lowest terrace region. They are clearly
visible on the aerial photographs due to contrast in color between the ridges
and sloughs.
Chute cutoff resulting in isolation of a part of a point bar, and neck cutoff
resulting in preservation of a complete meander are clearly visible on the aerial photographs. An erosional speed of 70 meters a day has been observed
45
locally. Oxbow lakes containing water during the whole year are present at the
southern side of the Euphrates valley.
The lowest terrace is prehistoric up to Byzantine (v.Liere 1960-1961)
c. P l e i s t o c e n e
c . l . The if1
terraces.
Euphrates terrace or Main gravel terrace (T2) lying 15-28 m
above the flood plain and having a thickness of 12-22 m.
The boundary between T 2 of the Hamret terrace region and T^ is marked by a
12-15 m escarpment, while the transition of these terraces in the Raqqa area
is more gradual.
c.2. The III
Euphrates terrace (T„) is lying 30-50 m above the flood plain
and has a thickness of 10-25 m. The boundary between Tg and T_ is marked locally by an escarpment of 15 m.
c.3. The IV
Euphrates terrace (T.) is lying about 65 m above the flood plain
and has a thickness of approximately 10-15 m.
T 2 and T of the Raqqa terrace region have a rather flat topography.
Fig. 9. Legend morphological map.
^k*^*v Perennial river.
*<* Ephemeral river, wadi.
*"
- Boundary of morphological regions.
Topographical boundary.
.•.'.
Dolines.
« Tal.
<& Village.
t^J
Area with human activity.
Fl PI
Tl
T2
T3
T4
BT1
BT2
G
L
M
V
Bas
Lapfl)
F
R
K
Flood plain of the Euphrates.
Lowest Holocene terrace of the Euphrates.
Upper Pleistocene terrace of the Euphrates.
Middle Pleistocene terrace of the Euphrates.
Lower Pleistocene terrace of the Euphrates.
Holocene terrace of the Balikh.
Upper Pleistocene terrace of the Balikh.
Gypsum.
Limestone.
Marl.
Volcano
Basalt.
Lapilli.
Foggaras.
Water reservoir.
Karst.
47
Escarpments mark the transition to Balikh and Euphrates and the transition of T.to T_. Miocene sediments are exposed in the north-eastern scarp of
T. to the Balikh. West of Raqqa the transition of T to T is more gradual.
The terraces of the Hamret region have a very hilly topography due to an
intense erosion. Wadi Hamret Naser is getting drainage water even from the
Gypsum region.
After formation of the Upper Pleistocene terrace there has been an erosive
period as is indicated, among other things by the valleys in T_, the incision of
the Balikh and the formation of the Holocene Euphrates valley.
Some flat patches in the Hamret terrace region can be encounterend east
of Hamret Naser and at the confluence of several wadis feeding the lower course
of Wadi Hamret Naser.
The terraces are covered with a loam mantle. Escarpments and tops of
hills are built up of gravel.
2. BALIKH TERRACES AND FLOOD PLAIN
The Balikh valley from Hawije to Hazimah is about 4 km wide and below
Hazimah 1 km. This narrow lower course and the occurence of medium shallow soils indicate the young stage of formation. Deeper soils are found in the
large mouth into the Euphrates valley. This probably is an old meander of the
.Euphrates.
a. F l o o d p l a i n .
a.l. T r a j e c t
Hawïje-Tal
es
Samen.
Drainage water of the adjacent high lands is divided over two streams the
Nahr Balikh and Wadi al Kheder.
The Wadi al Kheder gets its water mainly from the Wadi al Himar, a wadi
streaming north of the limestone plateau and coming from the eastern high lands.
Also the Wadi el Burj is a tributary of the Wadi al Kheder.
Transporting power of the Wadi al Burj can be significant after torrential
rains as is shown by the numerous limestone blocks in the lower course.
The Nahr Balikh is connected with the Wadi al Kheder near Hawije and is
feeding this wadi. The Qara Mokh is an important tributary of the Nahr Balikh,
having supply of drainage water from a relatively vaste area.
48
The incision of the Nahr Balikh and Wadi al Kheder in the Lowest terrace
is respectively 4-5 m and 3-5 m. The Nahr Balikh is meandering in a flood
plain of about 150 m width. The flood plain of the Wadi al Kheder is about 5080 m wide.
a.2. T r a j e c t
T a l es
Samen-Hazimah.
The valley widens into a broad plain at the confluence of old and recent
Balikh valley. Depth of incision and width of flood plain of Nahr Balikh decreases due to capture of water for irrigation purposes (incision only 0,6 m).
Near Hazimah canalization of the Balikh was necessary to prevent a diffuse
river pattern with great waterlosses.
a.3. T r a j e c t
Hazimah— Raqqa
Samra.
The Nahr Balikh recovers from its waterlosses after the confluence with
the Wadi al Kheder and the tributary Wadi Hafsir. The incision of the floodplain rapidly increases from 1 m near Hazimah to about 3 m down stream.
b. H o l o c e n e t e r r a c e o r l o w e s t t e r r a c e (BTj).
This terrace is a flat down valley sloping terrain. The elevations near
Hawfje and Raqqa Samra are respectively 305 m and 241 m. The slope gradient
over the traject Hawïje-Hazimah is 120 cm per km and that from HazimahRaqqa Samra 70 cm per km.
The terrace is built up of brown loams with a thickness of more than 3 m.
In the northern part marls are outcropping. Between Hawfje and Hazimah there
are several tals. The erosion rests of the adjacent terraces in the lower course
have been inhabited also.
Tal es Samen is about 20 m high above the terrace. The tals initially started as dwelling places on higher parts in the Balikh valley, this being
useful for protection against high spring floods. They have grown upwards on
account of the materials left by the successive inhabitants.
Recent villages have been built also on the higher parts of the Lowest terrace.
49
c. Upper pleistocene terrace (BT ).
Rests of this terrace are found on the right side of the Balikh valley. It is
built up of gravel and underlain by proluvial gypsum on limestone. Outcrops of
limestone are found on the higher hill tops.
The terrace is lying 5-25 m above the lowest terrace and is about 5 m thick.
Breccious material at the foot of the limestone massif will have the same
age.
3. VOLCANO REGION
The volcano is situated in the centre of this area with many ash piles in
the crater. These piles have an elevation of 400 m, that is about 160 m above
the terrace level.
The bottom of the crater has its lowest point at 120 m below the top of the
highest ash pile and the crater sides rise about 100 m above the surrounding
lapilli. The sides become very steep near the edge of the volcano.
A subcrater formed on the southern slope of the crater.
In the first stage of formation an extensive cover of lapilli formed on the
terraces. The thickness of this cover at some distance of the volcano is 6-12
m, a fact concluded from deep borings.
Mega-ripples have been formed by wind action in the coarse-textured lapilli.
This is clearly visible on the aerial photographs where a striage with dominant north-south direction was observed. This preferred direction will be due
to the predominant western winds.
The topography of the lapilli region is slightly undulating and determined
by numerous shallow valleys and small isolated hills.
The drainage pattern is more or less radial from the volcano out to the
lower terrains, but becomes rather diffuse in the lapilli.
In some places the substrata are pressed upwards and domes formed r i s ing about 11 m above their surroundings. The lapilli in these domes is cemented by gypsum and lime.
In the II stage basalt streams have flown over the edge of the crater at
the northern and eastern side. They have a maximum extension of 4 km and a
thickness of 6-10 m (deducted from the topographical map)..
Some valleys formed in this basalt and the surface is covered with basalt
blocks.
50
Fig. 10.
Kaistvalley; collapse sink developed in gypsum.
Therefore, the gypsum deposits weathered to clastic deposits with angular
grains by chemical and dominant physical weathering.
The gypsum can go easily into solution and crystallize to a dense mass.
The formation of crystalline gypsum in places where water comes to a
standstill in wadis will be the first stage of karst development.
Gradually solution and recrystallisation of gypsum sand will increase. The
zone of recrystallized gypsum will gradually move downward and a doline
forms with gymsumstone at the sides.
5. LIMESTONE REGION
The north-northeast—south-southwest direction of the Balikh fault has influenced the direction of most escarpments.
In Pleistocene times the limestone region was deeply dissected and no
karst was formed. The surface of the rock was only slightly attacked by chemical solution.
The deep incision and lack of karst may be due to a poorly developed jointing system.
These limestones are not folded intensely and therefore will not have
been subject to high stresses, giving rise to pronounced jointing.
Highly jointed limestones are found in the folded areas of the Libanon ranges and Turkish mountains.
52
4. GYPSUM REGION
This region is bounded to the north by a limestone massif, to the west
by a 20m escarpment to the Balikh and the gypsum is overlain in the south by
gravel of the Lower Pleistocene terrace.
The gypsum deposits have a sandy texture and locally clay layers are intercalated (for further details one is referred to chapter HI, D, 2 and IV, 2).
The Pleistocene gravel has protected the softer gypsum deposits.
When the Balikh changed its course at the end of the Upper Quarternary,
some north-south draining wadis were captured by the east-west draining Wadi
Hafsir. The present-day direction of drainage is from east to west except in
the extreme south where wadis drain towards the Euphrates valley.
Human activity has influenced the morphology in some places e.g. foggaras in the Wadi Hafsir, and Tal Jebel el Udwaniya.
The valleys of the Gypsum region are typical karstvalleys. A karstvalley
is a transitional stage between surface drainage and underground drainage. (Thornbury 1954).
Dolines as wel as collapse sinks occur.
Dolines develop slowly downward by solution without physical disturbance
of the rock in which they are developing.
Collapse sinks are produced by collapse of rock above an underground void.
Several karstic features, such as bridges, natural tunnels and swallow holes
were observed.
Caverns do occur at the Euphrates escarpment outside the region. In one
of these gypsum stalactites have developed.
No karst has been found in the Limestone area.
The Lower Quarternary proluvial gypsum deposits are relatively stable
since they have survived the pluvial Pleistocene periods.
During the Pliocene-Pleistocene the Tertiairy deposits were attacked
heavily by erosion forces.
The limestone weathered to a calcareous loamy residue (chapter HI, D,l).
Much of the calcium carbonate has gone into solution and has been transported
as calcium bicarbonate with the drainage water to the sea. In pluvial times
there must have been a quite luxurious vegetation on the weathered limestone
resulting in a leaching of carbonates.
This can not have been the case with the gypsum deposits, having a deficiency in plant nutrients.
51
C. H y d r o l o g y .
Hydrology as influenced by climate, geology, morphology and human, activity is discussed below.
Human settlement is restricted to the coastal regions with higher rainfall
and to the regions with easily accessible drinking water e.g. the oases of Aleppo and Damascus, the rivers Orontes and Euphrates.
Central and south-east Syria have a low precipitation and limited groundwater source and therefore a very small population.
1. HYDROLOGY OF SYRIA
The curves of equivalence of aridity indices given by Abd al AI coincide
withe the major hydrographie regions., These curves are shown in fig. 3.
The 25 index curve encloses the basin of Lake Antioch.
The 15 index curve corresponds to the watershed between the areas of seaward and inland drainage in the west. Thence it runs northward and swings east
over the source regions of Khabour and Balikh.
The 5 and 10 index curves are the boundaries of the Dead Sea basin in
which the Damascus basin is included climatologically.
The 4 and 5 index curves delimit a waterless basin opening soutward.
The present hydrological pattern shows few;perennial streams.
The limestone massifs in the Libanon and Turkish mountains serve as water stores.
There is rapid run-off as a result of the heaviness of the downpours, however, part of the rainfall is captured by the many fissures and karstic features
of the limestone in these mountains.
Perennial rivers such as the Euphrates and Orontes have their water supply especially in summer from such catchment basins. Also the closed basins
of Damascus and Aleppo are watered by streams fed by great storage massifs.
The Euphrates flows over about 540 km of Syrian territory. The average
water level in the river at the Turkish frontier is 326 m and at the Iraqian frontier 170 m. Nearly all the water originates from the Turkish mountains in the
north while in the desert there is only occasionally some superficial supply. In
spite of withdrawal of water during summer for irrigation purposes there is
still a relatively high amount of water due to a supply of groundwater between
53
Deir ez Zor and Abou Kemal.
2. HYDROLOGY OF THE BALIKH BASIN
The Balikh Basin is lying in the Euphrates Basin, draining towards the
Persian Gulf.
a. S u p e r f i c i a l
water.
The average discharge of the Euphrates near Deir ez Zor is 735 m 3 sec.
The minimum, maximum and average discharge of the Balikh at the confluence
with the Euphrates are respectively 0-5, 12 and 6 m'Vsec.
Rainfall in the upper course of the Balikh is 452 mm at Urfa and summer is
nearly dry. Some sources near the Turkish frontier supply water during the dry
summer too.
Difference of water level between summer and high spring floods is about
3m in the Euphrates river.
However, in early historical times the water level was higher than it is
today.
A Roman channel on the southern border of the Euphrates, 20 km west of
Raqqa, had its inlet at about 256 m while the level of today in that place is 246
m.
The inlet of the channel of Haroun al Rasheed was at a height of about 250
m where the present day water level is 243,6 m. This channel stems from Abassid time about 800 A.D. and its inlet is situated at about 12 km west of Raqqa.
The lowering of the river level in historical times will be due to an increased erosion of the Euphrates in its own riverbed as a consequence of increased
spring floods and decreased supply of valley debris. The spring floods are
more pronounced owing to a quicker melting of snow in the Turkish mountains.
The terrace and proluvial gypsum deposits drain towards the Balikh and
Euphrates valleys. Wadi Hamret Naser has a vast collecting-reservoir of drain
water, evidence of an impermeable underground. This could be due to the presence of Pliocene clay and cemented gravel in the substratum.
54
b. C h e m i c a l
c o m p o s i t i o n and d e p t h of
groundwater.
The depth of the groundwatertable can be estimated by the depth and condition of wells.
Approximate depth of groundwater:
.
.
Euphrates region about 5 m.
Lower Balikh region 5-10 m.
Pleistocene terraces more than 20 m.
Volcano regions 25-30 m.
Gypsum region 15-30 m.
Limestone region 20-30 m.
The depht of wells indicate a lowering of the watertable. Most wells are
salty even in the Euphrates valley.
However, fresh water may occur in the valleys of Euphrates and Balikh.
The groundwater of the flood plain of the Euphrates is of the hydrocarbonate type while the groundwater of the lowest terrace is of various composition.
There are no wells in the middle Balikh; the water is supplied by the Nahr
Balikh and Wadi al Kheder.
Depth of groundwater can be only a few meters during spring and winter
time in the Lower Balikh and Euphrates.
The Hamret terrace is only populated in the south. These people get their
water supply from the Euphrates.
The Pliocene underlying the terraces and volcanic deposits is characterised by a magnesium-calcium-sulphate type of groundwater (content of salts
1,5-2,8 gr/1).
The lagoonal Miocene is characterised by a mixed sodium-potassiumchloride-sulphate type (content of salts 3,2-6,5 gr/l) of groundwater.
So far the basaltic rocks have not very much influenced the chemical composition of the groundwater.
The most favourable water type is the groundwater of the flood plain of the
Euphrates.
c. S t o r a g e and u s e of w a t e r by
man.
The Balikh Basin was inhabited long before B.C. as is proved by the
presence of tals in the Balikh valley which have been built up between 25005600 B.C.
55
Raqqa's history dates back to Alexander the Great.
In Roman time technique of storing water in cisterns was developed.
Larger underground water reservoirs built up of stone are still in good
condition in the Roman ruins of Rasafah.
Human activity to store water is also pronounced in the Balikh Basin.
In the past foggaras and a large surfacial waterreservoir were constructed
(see fig. 9).
The fogarra consists of a number of shafts at more or less regular distances in a wadi driven to an impermeable layer and interconnected with each
other by a tunnel.
In recent times earth dams have been built in water-rich valleys (near Tal
es Samen) and near springs (Ain Isa and Ain Arus). The stored water is used
for irrigation.
Wells dug with a diameter of 3-5 m are being constructed in the lower
Balikh and Euphrates valley. They are used for irrigation purposes. Wells with
a diameter of 1-1,5 m have too low a capacity for irrigation, and supply water
for domestic needs of a family and for livestock only.
Pumping of Euphrates river water for irrigation of low and high terraces
is practised extensively.
In spite of human effort to overcome excessive dryness of the climate, man
has not succeeded in becoming independent of the unfavourable climate.
A short term drought like that during 1955-1962 caused a depletion of fresh
water reserve in many parts of the country. Many abandoned villages in the Jazirah bear witness of the shortage of drinking water.
The reserve of fresh water is decreasing owing to the increasing number
of wells and pumps, and the increased population with a higher standard of living
and better technical resources.
56
CHAPTER
m
MINERALOGY
Mineralogical analyses can be used for the determination of the homogeneity of the soil profile and contribute to the distinction of soil-forming processes and the determination of soil fertility (Doeglas 1960).
However, to be able to appreciate the soil forming processes it is neces.sary to have knowledge of the mineralogical composition of the various grain
size fractions.
For this purpose these fractions were analysed by different methods, viz.
a. X-ray diffraction, giving the kind of minerals, by determining the specific
crystal patterns;
b. X-ray fluorescense, giving the chemical composition of the fractions;
c. microscopic study, also giving the kind of minerals.
These analyses were applied to various fractions:
1. the clay fraction smaller than 2 p. by methods a and b;
2. a small number of selected samples the fraction 5-10 n by methods a and b;
3. another small number of selected samples the fraction 20-30 M> by method b;
4. the sand fraction 50-500 n was studied by method c (heavy and light minerals).
5. the total fine earth, that is soil material smaller than 2 mm, was analysed
after method b, showing most of its chemical composition.
The mineralogical composition of the different fractions is discussed below
while the data of the X-ray fluorescence examination are presented in chapter
VUI.
57
A. MINERALOGICAL ANALYSES OF THE SAND FRACTION. (50-500 g,)
1. ANALYTICAL METHODS
The pretreatment of the samples was done after the following standard
method. The fine earth was treated with 30% hydrogen superoxide and 0, 2 N
hydrochloric acid, after which the fraction 50-500 n was separated by sieving.
Heavy and light minerals were separated with the aid of bromoform (s.g.2,9)
The heavy minerals were mounted on a glass-slide with the aid of canadabalm (n= 1, 537) at a temperature of 130°C. They were determined and counted
under the polarization microscope.
For light minerals this was done in a liquid nitrobenzol with n= 1, 552.
The use of nitrobenzol was proved to be useful for determining the plagioclase feldspar in having about the same refractive index as intermediate plagioclase.
The magnetic fraction of some samples was examined by X-ray diffraction.
2. PROBLEMS IN CONNECTION WITH THE METHOD USED
The soil material of the Balikh basin is very rich in minerals which easily
dissolve during the pretreament of the samples. Preliminary observations proved
that the soils contain larger to smaller percentages of calcite, gypsum, anhydrite
and olivine. These minerals partly (disappeared I during the pretreatment or the
shape of the minerals was highly transformed. The gypsum crystals disappeared
largely while the remaining dehydrated after drying the sample at 1O5°C, into
hemihydrate CaSO 4 . |H 2 O.
Dehydration of gypsum takes already place at about 38°C. To estimate the
real amount of gypsum, drying should to be done at 35°C and HC1 cannot be used
owing to the high solubility of gypsum. Nevertheless, some gypsum will be dissolved already in the aqueous suspension of the soil..
From an original content of about 40% olivine of the heavy fraction only
10-20% is supposed to be left after treatment. Therefore, the estimated percentages of the easy soluble minerals should be evaluated as being much higher
on the original sample. These minerals are found after treatment only when the
original content is high enough to survive dissolution.
A uniform treatment with exactly the same amounts of diluted HC1, diluted
H„O2 and fixed time of boiling for each sample could be a theoretical solution
58
but this cannot be realised in practice owing to the varying content of organic
matter, lime and free iron.
However, in order to get an idea about the content of easily soluble minerals, samples were treated with H2C>2 followed by drying at 35°C, only.
Olivine appeared to be considerably less corroded; the same was true for
anhydrite; calcite was found to be a common constituentof the soils and had a
weathered appearance; nepheline was found only in lower amounts.
Some soil samples were selected of a gypsiferous area and particular
attention was paid to the dissolving fraction.
The results after different treatments are given in table 13.
The profiles 1 and 3 have a soil horizon with accumulation of pedogenetic
gypsum, characterised by euhedral crystals. Profile 2 has below
the subsoil a soil horizon with geological gypsum, characterised by slightly
weathered oolitic gypsum crystals. In case samples got a pretreatment with
H2O2 and HC1 and drying at 35°C, most of the gypsum was dissolved, whereas
calcite completely disappeared.
Table 13. Percentages of easy weatherable minerals after HC1 treatment and after H O treatment only.
Heavy Fraction 50-500^
Sample
% Anhydrite
nr.
HC1
1I
1 II
1 III
tr
6
3
40
40
20
2I
2 11
2 III
4
3
5
3I
3 II
3 III
4I
% Olivine
HC1
Light Fraction 50-500^1
% Gypsum
2°2
HC1
4
7
1
5
14
2
30
23
30
16
9
10
3
2
1
36
45
28
0
3
H
2°2
% Calcite
2°2
HC1
0
tr
tr
8
14
47
0
0
0
tr
12
4
22
20
17
0
2
50'
5
63
86
0
0
0
10
4
0
12
4
2
21
12
21
0
0
0
7
5
16
0
0
0
24
31
20
75
76
0
0
0
26
H
H
H
2°2
Note: 'newly crystallised out of oversaturated solution.
Although the original content of olivine is higher than after HC1-treatment, 4 I shows an equal
percentage of olivine after H O treatment.
This is due to the fact that in this sample many olivine grains have an iron-coating, thus becoming opaque and not determinable after H O treatment.
2 2
59
3. PRINCIPLES AND METHODS OF HEAVY MINERAL RESEARCH
The principles of the so called "Dutch School" were applied. Originally
they were enunciated and elaborated by Edelman, and afterwards completed by
Doeglas.
The most important principles and definitions are as follows.
A "sedimentary petrological province" is made up by a group of sediments,
which constitute a natural unity by age, origin and distribution.
A province can exist out of several different associations. An "association"
is the combination of minerals by which a sediment is characterized.
So called "chance variations" will occur regularly. There are two types:
1. The distribution of minerals is not uniform in sediments, not even in sediments of homogeneous origin and texture. Therefore, the mineralogical
composition of one association can vary within certain limits.
2. Inaccuracy of the analysing technique (see section 2).
"Granular variations" are caused by differences in grain size e.g. fine
sand will be rich in fine grained zircon and tourmaline, and coarse sand will
be rich in coarse augite, diopside or olivine.
"Provincial succession": progressive denudation in the source area leads
to deposition of an association of new minerals on the older association, separated by a transitional zone with irregular variations.
"Provincial alternation": borderline between two sediments, covering each
other in turn over a given area.
The various soil mineralpgical investigations were carried out in the material of the first one or two meters of the earth's crust.
To evaluate the pedogenetic processes which play the most important part
in the top layers, it will be important to know the state of weathering of the parent material and what are the changes which took place in the soil in situ.
In the case of arid soils pedogenetic processes can be evaluated by studying
minerals formed or accumulated in Post-Pleistocene times.
For an understanding and explanation of the soil-forming processes it is
important to know the homogeneity of the soil profile. In the topsoils where the
greatest weathering of soil minerals takes place, admixtures transported by
wind can be encountered. Highly mixed topsoils can be regarded as compound
provinces, having an admixture of minerals from the surrounding mineral provinces depending on the prevailing wind direction.
Soil fertility is a function of the mineral richness of a soil. Study of both
60
heavy and light fraction will be necessary to evaluate soil fertility.
4.
DESCRIPTION OF MINERALS
The general descriptions of minerals are given in the textbooks of Heinrich (1965), Milner (1962)
and Kerr (1959).
In the review given below the special characteristics and varieties of several minerals that occur
in the Balikh Basin are given.
a. H e a v y
minerals.
Zircon often irregular habit, occasionally rounded.
Tourmaline, the variety schorlite with pleochroism from light grey to grey or nearly black, from
pale green to deep green, from pinkish to black.
Garnet, the varieties pale pink spessartite, pink to light red pyrope and colourles to yellow grossularite in variable amounts, sometimes also brown melanite in low amounts. Often inclusions, relatively large grains.
Spinel, the variétés brown picotite, occasionally colourless spinel, light green pleonaste and dark
green hercynite.
Zoisite: distinction was made between zoisite with normal interference colours and abnormal
interference colours. Fe-rich zoisite, having normal interference colours and a higher birefringence
than normal zoisite occurred in lower amounts. Thulite with pinkish pleochroism occured in a few
samples.
Clinozoisite has oblique extinction. Distinction could be made between clinozoisite with normal
interference colours and abnormal interference colours.
Fe-poor clinozoisite has larger extinction angles than clinozoisite. A yellow green 1st order interference colour is highly characteristic for clinozoisite. Clinozoisite with normal interference colours
is far more common than the other varieties.
Epidote has relatively large strongly weathered angular grains, weakly pleochroic from colourless
to greenish yellow. Bright and purple interference colours are highly characteristic; occasionally twinning.
Pyroxenes: the term clinopyroxenes was applied to diopside, augite, pigeonite and aegirine, only
titano-augite has been indicated in the table separately.
Diopside was relatively fresh and colourless to pale green, occasionally twinning. Augite is more
weathered and more yellow green as compared with diopside; also light brown types and weakly pleochroic.
Augite of the Volcano area has prisms with bipyramidal terminations, low birefringence, biaxial
positive 2V=60u, often zoned; often in cluster of 5 or more crystals.
Titano-augite is weakly pleochroic and has characteristic brown, purple or reddish colours.
Pigeonite is more strongly weathered than augite; clear bright interference colours; 2V small
0-32°.
Amphiboles: distiction was made between green hornblende, pleochroic from yellow to green or
light grey green to grey green, and brown hornblende pleochroic from yellow to brown. Occasionally
twinning of green hornblende.
Uxynornmende nas a higher birefringence and is more strongly pleochroic than brown hornblende;
opague borders or inclusions.
Glaucophane weakly to strongly pleochroic in bleu and purple colours.
Grunerite, anthophyllite, tremolite, actinolite and cummingtonite occurred in lower amounts and
therefore have been registered as accessory minerals.
Olivine, mainly forsterite, colourless, sometimes yellow to green. Pleochroic fayalite occured
sporadic. Grainsize often relatively large. Phenocrysts often have inclusions of augite microlites. Penetration twins occur, biotite flakes are sometimes attached to the grains. Olivine derived from basaltic
rock often has a brown or black iron coating.
61
Altetite is a weathering product of zoisite and clinozoisite; irregular grains with greyish weathered
surface.
Saussurite is a weathering product from epidote; greyish colour; on the corners a purple and/or green
interference colour.
Anhydrite has a higher birefringence than gypsum. Habit mainly denticular, furtheron rectangular,
euhedral, fragmental, composite sheaf and oolite types (see fig. 14).
Apatite and titanite are registered under accessory minerals.
b. L i g h t m i n e r a l s .
Quartz is occurring in mainly subrounded and subangular forms.
All main types of quartz were recognized. These are:
a. metamorphic quartz with wavy extinction and inclusions;
b. igneous quartz, being nearly equidimensional and without inclusions;
c. sedimentary quartz, being highly rounded, frosted and with overgrowths; also chalcedony with pseudo-interference figures belongs to this group.
Sedimentary quartz is the most abundant quartz type in the region.
Volcanic glass is amorphous, colourless but also light greenish grey, often perlitic fracture, irregular, rounded and angular grains occur. The lapilli contained glass with inclusions of augite
and a few olivine microlites.
The grains of augite and olivine at the time of cooling of the magma were embedded in a mantle
of volcanic glass.
Phytoliths (SiO.. nH 0) are amorphous plant made materials.
Their shape can be related to the place of formation in the plant, (see Chapter V for further details).
The grains are transparent and often have a light pink color. They remain extincted during rotation using crossed niçois.
Other names are: hydrated silica, opaline silica (Smithson 1956), kieselkörper (Netolitzky 1929)
and organic SiO^ (v. Rummelen 1953).
Feldspar:
Sanidine has a smaller 2V than orthoclase, and is more turbid.
Orthoclase is biaxial negative, grains are clear and have often inclusions.
Microline has a tweed-like fabric (combined albite-pericline twinning).
Acid plagioclase=albite+oligoclase; negative relief in nitrobenzol; biaxal positieve; albite twinning and carlsbad twinning; occasionally inclusions.
Intermediate plagioclase=andesine+labradorite; refractive indices near that of nitrobenzol; albite
twinning and also carlsbad twinning.
Basic plagioclase=bytownite+anorthite; positive relief in nitrobenzol; albite twinning and carlsbad
twinning.
Sanidine, microcline and basic plagioclase occurred only in small amounts.
Muscovite with s. g. = 2, 76-3,0 (Milner 1962), colourless; the grains have a low birefringence owing
to their platy character and are generally five times larger than the average grain size of the other
minerals.
Mainly colourless phengite with 2V=0-20 ; also fuchsite (metamorphic source rock) with a pale
green colour. Muscovite occurs in light as well as in heavy fraction owing to its intermediate specific
gravity as compared with bromoform (s.g. ~ 2, 9).
Gypsum becomes dehydrated during treatment and alters intho hemihydrate.
In fresh condition gypsum is often covered by a coating of calcite.
For crystal habit and discussion see fig. 14 and section A, 6 of this chapter.
Calcite has a high birefringence; hexagonal; rounded or angular habit; weathered appearance in
fresh material; goes completely into solution after treatment with 0, 2 N-HC1.
Weathering products, distinction is possible between light brown to brown weathering products
from gypsum, and grey weathering products from feldspar.
62
5. MINERAL PROVINCES AND ASSOCIATIONS
An abundance of feldspar, mica, gypsum, anhydrite and calcite is generally characteristic for sediments from semiarid and arid climates.
Although the content of light minerals generally is more than ten times
as high as that of heavy minerals, the mineral association was defined by the
heavy mineral assemblage, being the most characteristic of the sand fraction.
The Balikh Basin can be divided in the following mineral provinces:
1. Euphrates province; deposition in Hofocene times.
The mineral assemblage of the examined surface layer is related to present
day sedimentation in the Balikh.
2. Terrace-Balikh province; deposition at the end of the Upper Pleistocene and
in Holocene times.
The loamy cover of the terraces is supposed to be slightly older than the
valley fill of the Balikh. Owing to origin, age and mineral distribution Terrace and Balikh can be seen as one mineral province, divided in four associations.
3. Volcano province; deposition of lapilli at the end of the Upper Pleistocene.
There is a transition to the Terrace-Balikh province, and the surface layers
have an admixture of minerals from this source.
4. Gypsum province; deposition at the beginning of the Lower Pleistocene, but
in following periods eroded and redeposited for repeatedly times.
On the surface deposition of material from the Terrace-Balikh province;
the boundary of this material with the underlying gypsum is rather abrupt.
As will be clear from the statements made above, the mineral assemblage
of the Terrace-Balikh province plays an important part in the top layers of
soils from the Gypsum and Volcano regions which is favourable to their agricultural value.
The top layers of these soils as well as the transition from terrace to
volcano are regarded as compound provinces.
Table 14 gives the results of mineral counts of 100 non opaque minerals
while the opaque minerals are expressed as a percentage of the total heavy
fraction.
63
. TABLE 14: HEAVY HIHEHALS OFTHE BALIKH BASH
Sample
depth
in
en
Hr.
* Light % heavy
Bin. of a i l . of
soil
soil
< 2 ma
a
1
9
t.
t.
r*
*4
+>
a
0
M
O
O
CD
<
**
«
CO
Euphrates
20
20
20
20
33
33
I
II
III
IV
I
II
0-5
30-35
60-65
85-90
13-20
40-50
8, 1
0 ,2
2,8
0,02
4 ,6
3 ,6
0
0
0
0
0
0
I
II
III
IV
I
II
III
IV
0-12
15-25
40-50
90-100
3-7
20-26
47-53
0
0
0
0
,3
,3
,2
,2
1 ,4
1,2
0, 5
1, 0
0 ,1
0 01
0 01
0 01
0 1
0 ,1
II
I
II
I
II
III
IV
V
VI
I
I
II
III
IV
V
30-40
0-10
30—40
0-4
5-10
13-18
25-30
45-50
75-80
0-10
0-8
15-22
36-40
60-65
85-90
,3
0,4
.8
,1
,07
,003
,4
,4
7
7
5
5
19
1
1
2
10
Ü
•H
3 1
1 3
2 tr
1 tr
tr
5 1
Transparent ha&T? mina rais 1n nntuB 1 pe r c e nta« s
•
S
V
g a •a
*>
e
1
te
a
•a
a
e
c
0
0
a
I
1
•r«
•H
|
S
1
1
1
1
8
d
0
s s
I
1B
1
4
tr
1 3
1 2
3
5
6
7
6
9
4
20
19
30
25
27
20
26
11
9
8
14
14
6
6
3
3
3
6
1
1
4
3
9
19
15
14
11
23
27
12
24
13
20
29
30
29
30
36
25
19
30
26
34
40
17
3
7
3
5
2
g
26
17
19
15
29
28
25
2
17
16
19
18
17
19
19
18
19
24
39
36
40
39
42
35
3
2
20
19
16
10
• -
a
i
1 1
11
15
11
6
8
6
6
12
2
5
5
6
20
24
19
28
25
35
1
3
6
3
4
3
8
7
6
9
7
9
11
1
4
1
1
tr
tr
5
6
8
9
6
11
12
2
4
4
3
7
2
3
tr
13
5
10
1
1
1
2
4
9
4
tr
2
2
4
10
1
1
1
1
12
10
11
13
8
?
A
4
6
12
6
9
6
tr
5
2
2
7
1
12
9
10
1
3
3
5
4
9
1
2
18
16
8
7
16
21
4
2
2
12
22
20
tr
2
1
19
17
9
10
9
s
0
1
tr
tr
• -H
*» U
a
X
3
0
1
1
1
3
2
1
1
1
1
1
Balikh
15
15
15
15
27
27
27
27
25
7
7
8
8
8
8
8
8
9
34
34
34
34
34
77-83
2
Q
1 2
1 3
1 4
0 ,8
0
,8
3
6
3
3
3
,2
0 2
0
0
0
0
0
1 17
14
1 17
1 6
1 11
1 6
tr 9
1 6
tr 4
4
1 3
g
6
2
2 7
1 10
1 10
1 5
1
1
0 ,1
0 1
3
0 2
0 03
0 02
0 1
0 2
0 1
0 1
0 05
30
28
24
26
32
28
21
26
30
30
17
20
23
34
28
33
17
0 05
0 03
0 01
0 01
0 01
0 02
13
33
38
32
26
29
1
1
1
1
tr
7 1
2 3
6 tr
9
tr
3
3 tr
5
6
1
2
6
tr
1
1
8
1
1
tr
1
6
1
2
1
1
1
1
tr
1
2 tr
tr
1
tr
3 1
4
tr
3
2
1
1
1
1
1
tr
tr
1
tr
tr
1
1 tr
tr
tr
1
5
5
2
4
1
1
20
1
1
3
2
2
1
2
1
1
14
8
11
10
10
6
7
10
1
tr
1
2
1
tr
tr
tr
tr
2
1
2
2
4
1
tr
4
52
5
5
2
5
3
2
tr
2
tr
tr
1
8
1
tr
1
tr
8
11
10
11
7
1
1
1
tr
4
7
4
4
4
2
6
6
6
7
2
4
5
3
3
3
6
7
6
9
6
2
3
5
6
5
3
2
7
3
2
2
5
4
2
3
5
6
3
5
2
3
2
2
4
2
2
9
6
11
1
1
1
2
1
1
2
1
1
1
1
2
3
1
5
1
1
1
Balikh19 IV
19 v
90-95
140-150
Baqqa
terrace
24 I
0-8
24 II
8-15
24 l i t 15-43
24 IV
71-79
26
26
26
26
0
0
3
1
13 6
0
03
0
01
1,
1
6
5 3
5 6
0
0
8
7
31
23
33
34
7
2
8
4
0
0
0
1
2
3
0 4
32
25
40
33
12 j
2
.r t r 8 t r
1 7
1 t r 12
1 tr
1
Q
3
1
1
1
I
II
III
IV
0-10
10-20
25-35
50-60
3
2
2
4
32 II
32 III
32 IV
20-30
40-50
70-80
1 9
1 7
2 9
0 2
0 1
0 3
29
30
40
0-8
15-25
40-50
75-85
n a.
n B.
n n.
n a.
n a.
n a.
n a.
»• a .
13
13
11
13
0-10
30-40
5 7
4 6
0
0
4
5
26
30
2
13 t r
3 tr 6 3
0-10
6 5
0,
7
26
3 tr
1 2
2, 4
0
0,
4
4
26
26
9
1 10
2
2
8 1 tr
8 tr
1
6 tr
2
3
4 tr
8
7
7
2
2
1
1 tr
2 1
5 tr
1
1 1
tr tr 1
1
3
16
26
2
1
1
2
13
11
25
18
1
1
1
2
4
2
1
13
9
13
17
19
27
32
31
3
3
2
3
17
18
28
28
1
8
4
3
11
15
20
26
25
27
28
30
2
2
tr
13
12
10
5
1
4
8
14
16
22
2
1
18
17
3
2
7
15
18
2o
35
7
S
7
3
21
29
30
25
3 tr
2
2
6
6
15
7
21
14
12
12
13
18
tr
2
5
2
2
1
tr
tr
1
4
tr
tr
5
tr
3
5
3 79
8
7 6
11
2
tr
7
12
14
5
6
tr
tr
2
tr
tr
1
7
13
7
7
9
5
3
3
tr
tr
tr
1
1
tr
1
4 5
5 9
5 17
3 11
4
6
11
5
4
4
1
1
.1
1
4
3
7
6
2
4
1
6
5
12
9
3
4
7
5
1
tr
tr
1
tr
9
6
2
7
4
9
7
1
6
6
1
2
18
13
2
2
12
9
1
2
tr
tr
tr
4
8
6 13
0 4
16
3
10
6
1
1
4
5
4
9
7
2
5 11
1 8
7
4
9
9
2
6
1
tr
6
12
7
3
4
2
9
8 tr
16 1
13 1
1
1
18
10
9
5
6
8
7
2
3
4
6
2O
10
1
1
Hamret
5
5
5
5
I
II
III
IV
28 I
28 II
29 I
V.lltj f i l l of
O7PB1W region
14 I
0-10
14 II
40-50
Valley fill of
Linesto ne regio n
0-10
0 6
6 I
0 7
30-40
6 II
0
0 1
1
31
21
Transition
Terrace-Volcano
12-17
17 I
32-57
17 I I
17 I I I 62-67
17 IV 110-115
0, 3
0, 1
ot 4
0, 3
20
23
20
21
64
2, 5
9 7
3, 6
2, 3
1 8
8
tr tr
S
1
1
tr
1
tr
1
tr
1
1
2
1
2
7
4
2
;r
tr
1
1
tr
1
2
1
7
1
tr
24
46
14
17
4
tr
1
2
tr
tr
1
tr
10
s
1
1
1
1
1
tr
2
tr
7
11
1
H*-
0
vf ru
D D D
D D P
P P D
HvO
H fU
00
B
OAO
0 0 O \ H ON
B B B
B B B
B B B
000000
O O O O
O O
0 0
O O
I\J H
0
D
H
ru
P O P
D D P
H
Vf
»1
H
ru ru
B
88
o"
ru
•
tr
0 --J -g 00 00 0
rt
rt rt rt rt
ru H
H
Vf IU
38
(U
ru
ru Vf
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tu H H H
Vf Vu Vf -N]
ï ru H
rt rt
H *t H
H Vf
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H *i
ru
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M »-• O H H
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B B B
*-> fW OSHUI
Vf 0^ -^ Vf
-» H l\)
ru ru ru
* " -P~Vf
rt
•ï
« &Ü £.&
H ru ru H
Vf *O H -O
Opaqu«
M H
Zircon
rt rt
H H 1
«t rt
vo Vn vn
rt H
et
H
H H
Vn O 0>
<
rt rt
1 1
j_, jj jj
OOH vn
rt
ft
rt
rt rt
JJHH
H
Tourmaline
H *i H
H H
H H
00 O -P""O Vf
rt
rt
rt
•1
t
t
i»SÎ
, ,
*1 H
H H *t
Vn H
A D B M
VWo
B
a a
*t
tr
H
a a
0 p- 0
B P«
rt
D"
1
t % heavy
nin. of
soil
< 2 um
H O
IU ON
TOO
AI i.
3-7
15-19
OTT-OOI
i
II
Vf ru
H O
12,4
10,2
10,1
14,0
12,3
O O H
Vf VO H O\
OOO H
f
I
5-10
0-10
38-42
83-87
0-5
10-14
28-32
52-57
82-87
30-40
45-55
7O-8O
30-40
III
iv
I
II
III
IV
V
I
II
III
\z 1
I
K2 II
0-10
25-35
-O
H
H
I
I
|* I
.P-^VO -P-ONO
*"&*
ru tu
50-60
70-80
[1 1
0-10
30-40
D
II
III
3 I
3 II
0-10
40-50
0
lolcano
lésion
\€ I
0-4
(6 II
20-30
[6 III
60-70
|6 IV 145-155
ypsun
e gion
1 I
1 II
0-5
15-20
lu \o
a
? 1 ?
-r-ff^voru^
H
H
f
L2 I
L2 II
1-6
30-35
i
LO I
LO II
0-5
25-30
60-65
0-5
8-12
23-27
38-U2
58-62
83-87
L3 I
i.3 II
13 III
I
II
III
IV
V
vi
Vf HVf
ïeavy minerais
rt
30
30
30
30
30
30
without anhydr
S"ü
ru ru Vn tu
ru
»1
Garnet
Spinel
Rutile
,
Brookite
Anatase
H
5taurollte
H
H
Kjanito
H
IU H
H H
Veeuvianite
Vf
t-1 »^
ru
ru ru
Vf
Vn -p-
t-> H H
ONH VO ru -J H
s
H IU
O.Vf
OOH Vf H O ru
Vn
« » »
ru -0
H
ru
H
ru
&%
M H
*- -p-
H
H Vf
OOH
H
G
ff
H
Vf
ru
19
16
21
Vf ru 00
H
fO vu -O
3
13
7
•p-fu ru
H
H1 H
•*>" H
•p-
•p-ru
Zoisite
H
C
H
H H
H
iu ru ru
vn * - ru
ru lu H H H
Vf vn ooooVf
H O OO
Vf -P-nj
* - ru vn
vn Vf
Chloritoid
H H
Clinotoisite
Epidote
l-> H *-•
Estatite
HH
ru
Hypersthene
H
H
IU H
H
W
H
OOVf
H
Clinopyroxene
Vf vn * • 00
rt
H
ru Vf Vf 0 »-s)
Vf H
vx
-O
H
*->}->
OOOO
ru
1
H
ru
Î H H
H
H ru
rt rt
*t *1
H H
rt
*1
H Î
rt
*i
HÔo-sJ
ru
•P-OO-P-
Hvnru
n.m
n.n
n.m
H
H
ru
t-> t^ h»
H H
iu
H *"-0
ON-O
H VU
H
H
H
H
Vf
H
tus î
vn -P-
UION
H
-P-ru ru
vn
H O-O
H
•P-H
rt rt
(U
H H
n
v?o
Ri
vn
sa
H
ru
H
ru H H
H *t 1
rt
OOVM >J O\
H
tu *- ru
H
H
H
Oojr jr-
W
H -r
ru
ru
Vf ru
Vf
Vf
H
ruv*
U VÔ
î
H-0 Vf
\O OoVJt
H
H
H
Oreen hornblende
Brovn hornblende
H
Vf Vf H V f vn
H
H
Qlaucophane
rt
ru O^> Vf ru
»!££<»
ro vn co\o Vf
H
vn vn
ON
Oxy-ho rnblen d e
00
Öl iTino
Alterite
Sausourite
Anhydrite
Variations in the percentages of one mineral within a province or association can be seen as chance variations as defined in section 3 of this chapter.
Granular variations will occur in the Euphrates province due to the alluvial character of the deposits with as a consequence variations in grain size between the different layers. The other provinces are quite homogenic in their
grain size distribution in the soil profile, so granular variation will not effect
the mineral distribution.
The situation of mineral provinces and associations found in the region is
given in fig. 11.
To illustrate the mineralogical assemblage of the different soil horizons
three levels were chosen, these are topsoil 0-30 cm, subsoil 30-60 cm and
deeper subsoil 60-100 cm. The heavy mineral assemblage is given for each of
these levels in a diagram indicated on the map in the centre of each mineral province and association.
Deposits found in the wadis intersecting the gypsum and limestone areas
are indicated as valley fill. If the valley fill was different from the surrounding
sediment, a diagram is given beside the sketch map.
In order to determine mineral associations, heavy minerals are discussed
first, while the light minerals are dealt with in section 5.b. of this chapter.
The Holocene basalt, Pliocene marl and Miocene limestone, shown on the
map (fig. 11) are discussed in subchapter D.
a. Heavy
minerals.
The mineral assemblage of the different provinces is given below:
a.l. E u p h r a t e s
province.
The valley fill of the Euphrates has a clinozoisite-epidote-green hornblende
association. The content of clinopyroxene is relatively high. Locally there is a
high content of titano-augite.
Soil texture and content of heavy and light minerals are highly variable
with soil depth. There is a lower content of epidote and garnet, a higher content
of green hornblende as compared with the Balikh. The content of clinozoisite is
high; only traces of olivine occur.
66
Characteristic are the fresh mineral grains and the low content of opaque
minerals, alterite and saussurite, pointing to a lower stage of weathering as
compared with the brown loams of the Terrace-Balikh province.
a.2. T e r r a c e - B a l i k h
province.
This province is characterized by an epidote-clinozoisite assocation.
The valley fill of the gypsum and limestone areas belong also to this mineral
association. Four associations were distinguished.
a.2.1. B a l i k h
association.
The Balikh sediment has an epidote-clinozoisite association. Locally
there is a high content of green hornblende .
The topsoil has a slightly higher content of heavy minerals as compared
with the subsoil.
The content of epidote and amphibole increases downwards in the soil profile.
Present day sedimentation in the Balikh is characterized by a high content
of clinozoisite, as has been proved by mineralogical analyses of profiles in the
Wadi al Kheder and the lowest terrace of the Balikh (respectively profile 7 and
8). The same is true for sedimentation in the Euphrates.
Characteristics of minerals:
Olivine from the Balikh province is. more rounded, often coloured and the
content of fayalite,' although low, is higher than in the Volcano region and related
provinces.
Intergrowths between clinozoisite and epidote occur. The garnet often has
a slight birefringence and inclusions.
Feldspar with inclusions is common.
a.2.2. R a q q a t e r r a c e
association.
The loamy cover of the Pleistocene gravel terraces has an epidote-clinozoisite-pyroxene association.
Characteristic is the moderate content of green hornblende, diopside,
augite and low content of pigeonite.
Garnet is sometimes rather weathered; fayalite occurs in subordinate
amounts.
67
O
4
8 km
I Tfaa.l ;O-SOc*.
I twMail ; SO-tOCM. B M
Oli.ta*
I 0««»t' »•»MU i
^ ^ |
«O-100 tat.
Ocraai
§§jSj§l Altanta «n«
^ - ^
•••••«'"•
is".v::r"" H •
o,...
«.....«.
v
v
j^^J
_ _
tdikh «tt«cl«li«* || | ||
.^.^
^ ".::::.:;:;••• EZ]
^
:
S
tairac* la
Fig. 11. Mineral provinces and associations of the Balikh Basin.
Note: The mineral assemblages were defined according to mineral content after pretreatment with
H2O2 and HC1 followed by drying at 105° C.
Easy weatherable minerals will have gone into solution during treatment. They have been
used for classification only where they are the main components of soil.
68
a.2.3. H a m r e t t e r r a c e
association.
The same association as for the Raqqa terrace, but a higher content of
olivine.
Loam near the volcano is highly mixed with lapilli, the influence and size
of grains of volcanic material decreasing with distance from the volcano.
In order to simplify the sketch map, the. whole Hamret terrace has been
considered to have the same content of olivine.
The magnetic fraction of profile 28 was determined by X-ray diffraction
and consists of hematite , amphibole , augite , ilmenite , magnetite and wustite; (+= 10-30%; no notation = 0-10%). The group of opaque minerals is mainly
built up of hematite and ilmenite, and low amounts of magnetite and wustite.
a.2.4. V a l l e y f i l l of the Gypsum and L i m e s t o n e
regions.
The loamy valley fill of these regions has an epidote-clinozoisite association.
The valley fill of the limestone region has a relatively high content op epidote and olivine.
The content o f alterite and saussurite is higher in the topsoil than in the
subsoil, pointing to a more intensive weathering in the topsoil, owing to water
from occasional rains coming to a stand-still in these valleys.
a.3. T r a n s i t i o n a l p r o v i n c e from
t e r r a c e to
volcano.
Loam with an admixture of fine-textured lapilli is underlain by gravel, and
has an epidote-clinozoisite-olivine association with locally a high content of
pigeonite.
Towards the volcano the loam becomes highly mixed with volcanic lapilli.
The weight percentages of heavy minerals are variable. Augite derived from
Upper Pleistocene volcanism is present in all samples; fayalite occurs sporadic.
a.4. V o l c a n o
province.
The lapilli soils have an olivine-pyroxene association in top and subsoil,
while the deeper subsoil is characterised by an olivine rich association.
69
In the upper part of soil clinozoisite and epidote are present in variable
amounts while they are lacking in the deeper subsoil. Locally there is a relatively high content of augite.
Weight percentages of light and heavy minerals are variable. Olivine from
the Volcano province was found by X-ray analysis to be forsterite.
The magnetic fraction from sample 22-1 determined by X-ray diffraction
•
consists of augite
i
[
i
, magnetite , wustite (FeO), hematite (QfFe.O ) and ilmenite;
(+++=50-70%; += 10-30%; no notation= 0-10%). It seems likely that part of the
opaque fraction is built up of augite microlites cemented
together after cooling
of the magma, the rest being magnetite, wustite, hematite and ilmenite. Microscopic examination of grinded opaque grains indeed showed microlites of
augite and magnetite.
The samples analysed were taken on various levels with different topographic features, but there is no mutual difference in mineralogical composition.
a.5. G y p s u m
province.
The topsoil of the gypsum deposit has a loamy admixture with an epidoteclinozoisite association while at greater depth the percentage of anhydrite is
high.
The transition from loam into gypsum is rather sharp. The content of anhydrite decreases in the deeper subsoil (fig. 12).
The topsoil is characterised by a higher percentage of heavy minerals as
compared with the subsoil, a phenomenon coinciding with the increase of gypsum
downwards in the soil profile and consequently a much higher percentage of
light minerals (fig. 13).
The heavy mineral content without anhydrite of the samples 30 IV-VI was
determined and compared with that of 30 I-HI.
This material is slightly different from that of the topsoil in having a higher content of opaque material, garnet and alterite while the content of clinozoisite is lower (table 14). The material of subsoil and deeper subsoil mixed
with gypsum and small quantities of anhydrite has apparently an older age than
the material of the topsoil, although the source region will be the same. Recent
mixing apparently takes place only in the upper 40 cm of soil.
70
d o
d 0
20
40
60
80
100
0
%
20
- profile 30
— profile 13
Fig. 12. Content of anhydrite
in gypsum soils
( heavy fraction )
b. L i g h t
40
60
80
100
% gypsum of total sand
% calcite of total sand
Fig. 13. Total content of gypsum
and calcite in fresh material
of profile 30
( heavy and light fraction )
minerals.
Minerals of the light sand fraction of the provinces defined above are shown
in table 15. The main light minerals of these provinces are:
b . l . Euphrates province with quartz, chalcedony, acid plagioclase and muscovite;
the content of phytoliths being relatively high; chalcedony points to attribution of limestone as a source rock;
b.2. Terrace-Balikh province divided in b. 2.1. Balikh association with quartz,
acid plagioclase and orthoclase; b.2.2. Terrace association with quartz,
chalcedony and acid plagioclase;
b.3. Transitional province from terrace to volcano with quartz and orthoclase,
and volcanic glass occurring in lower amounts ;
b.4. Volcano province with volcanic glass, orthoclase and quartz in the topsoil,
and volcanic glass as dominant mineral in subsoil and deeper subsoil; the
volcanic glass has inclusions of augite microlites, making the grains opaque
(the presence of augite was confirmed by X-ray diffraction) ;
b.5. Gypsum province with quartz and orthoclase in the topsoil and gypsum as
71
dominant mineral in subsoil and deeper subsoil (for details about gypsum
see below).
Table 15. Light minerals of the Balikh Basin.
Sample
8. 2
10
10
5
3
0,02
Balikh region
15 I
15 II
15 III
15 IV
0-12
15-25
40-50
90-100
0,3
0,3
0.2
0.2
29 9
33 22
30 13
34 15
2
1
0-10
30-40
0.4
0,3
28 14
29 10
1
1
Transition terrace- rolcano
31 I
0-5
10-14
31 D
31 m 28-32
31 IV 52-57
82-87
31 V
Volcano i ïgion
16 1
16 H
16 III
16 rv
Gypsum region
30 1
30 II
30 III
30 rv
30 V
30 VI
72
0-4
20-30
60-70
145-155
0-5
8-12
23-27
38-42
58-62
83-87
10 1
1-6
io n
30-35
12,4
10,2
10,1
14,0
12,3
34
28
34
36
1
1
24 7
35 5
28 13
25 15
29 14
2
3
3
3
1
3
5
3
2
6 8
7 9
6 14
3
48
31
33
90
5
13
4
6,9
6,2
4,9
9,4
7,6
4,4
22 8
24 10
26 3
2 1
2
12 3
1,0
8,1
26 5
2
E
11
22
12
19
28
4
6
10
5
13
20
25
17
1
7
1
2
2
2
2
1
2
12
18
15
16
4
5
8
3
1
2
2
1
1
1
2
1
6
13
5
16
10
2
3
4
2
1
6
2
17
16
1 16
2
1
1
10
1 10
1 8
26
16
21
25
23
1
1
2
• -B
8.E
S .8 ï S.
7
13
6
12
15
19
1
7
1
14
9
8
5
1
1
14
11
20
14
9
13
26
21
18
9
18
1
7
19
28
4
1
1
3
1
1 18
8
18
3
1
1
13
2
1
9
24
3
2
1
1
2
7
1
4
15
1
2
1
u
(0
1
9
1
1
.3
5
2
9 1
9 1
16
8
6
3
1
1
S
V
C
3
6
4
4
12
1
1
s
23
22
14
16
1
11
18
19
18
19
2,6
3.1
1.6
0.8
7
12
s .s
S
4>
cessoi
4
1
3
1
19
13
25
25
1,0
5.3
5.6
I
aE
17
10
11
10
8.1
0.2
2,8
13,6
=3 8
2s so
O.
0-5 >
30-55
60-65
85-90
Raqqa ter ace regie n
0-8
24 I
24 11
8-15
24 III 15-43
24 IV
71-79
-
° |a?
° ïl°
u
Euphrates region
20 I
20 II
20 III
20 IV
7 I
7 H
o"
S
îather ing
oduct!
1
'S S »
«
phelii
A
c glas:
clusioi
te + o]
ony
N
'c
ra
uscovi
cm
c
_al
c glas:
Nr.
Depth
in
weight
percentage
light
minerals
of
soil<2 mm
id pisLgiocll
terme diäte pla gioclaise
.sic pi agioclläse
j
Light minerals in mutual percentages
13
5
27
94
97
74
25
29
14
17
98
9
2
1
1
1
6. GYPSUM, HEMIHYDRATE AND ANHYDRITE
Gypsum dehydrates into hemihydrate at a temperature of about 38°C.
Hemihydrate has a higher birefringence than gypsum. The crystals are
etched and often oolitic after pretreatments with HgO« and HCl followed by drying at 105°C; extinction of hemihydrate parallel to direction of etching.
The light mineral fraction of sample 10 II was examined by X-ray diffraction and consisted for about 85% of hemihydrate. After drying at 105°C all
CaSO4.2H2O was dehydrated into hemihydrate CaSO..|H2O.
Hemihydrate can be formed only in the upper cms of soil where temperature
can reach values high enough for dehydration of gypsum.
Only in summer soil temperatures reach values of 42°C at 10 cm depth.
Measurements during the summer of 1965 dit not reveal higher values even
directly under the surface (0-5 cm), this being due to a high albedo. The reflection of sun rays is especially high in the light coloured gypsum soils.
Crystal habit of gypsum is given in fig. 14. Generally fresh gypsum is euhedral or rectangular, but fresh oolitic material was found, the crystal habit of
gypsum being often suitable for rounding. Boiling in H_02 and HCl can easily
round some types of gypsum euhedra. Therefore, it is necessary to study fresh
material before drawing conclusions about sedimentary origin.
In one case spherulitic structured gypsum with undulatory extinction was
observed. This was not encountered in the same sample treated with H„O
alone; both samples were dried at 35°C. Apparently the spherulitic gypsum must
be seen as a recrystallisation product of an oversaturated solution during treatment. The percentage of gypsum was determined in fresh material, light and
heavy minerals mixed in the sand fraction. This is shown for profile 30 in fig. 13.
Anhydrite had a diffraction pattern different from that mentioned in the
X-ray Powder Data File 1962, but was determined qualitatively by chemical
reactions on Ca (red flame) and SO. (the material gives after dissolving in
moderately concentrated HCl a white precipitate with BaClg -solution).
7. WEATHERING OF SOIL MINERALS
Minerals at the time of formation are in equilibrium with their environment,
but brought in new environments they tend to decomposition if enough moisture
is present.
73
Pathologie features, such as etched surfaces and corroded borders are indicative of instability.
For soil genesis the question arises: is the mineral at the place of weathering or did weathering take place elsewhere ? Therefore, it is necessary to
have some knowledge of the sedimentological history of the soil building material.
Since most soils of the Balikh Basin are alluvial (Balikh and Euphrates) or
aeolic (Terrace loams), material is not weathered entirely in the soil itself.
Only lapilli soils are practically in the place of primary deposition.
According to Hilgard (1906) the most striking difference between residues
formed in arid and in humid regions is the relative percentage of insoluble minerals, as are quartz and acid plagioclase.
Table 16. Percentage of insoluble material in humid and arid regions.
humid regions
arid regions
Balikh Basin
% insoluble material
84 (ace. Hilgard)
69 (ace. Hilgard)
56
Conditions of minerals were examined after a pretreatment with H.O_
followed by drying at 35°C or without pretreatments.
Quartz has brown coatings and is weakly etched; feldspar has a slightly
etched surface; basic plagioclase can be strongly weathered.
The crystal habit of olivine, gypsum and anhydrite after pretreatment with
H
2 ° 2 f o l l o w e d b v drying at 35°C or without pretreatment is given in fig. 14.
The percentage of different forms of olivine, .anhydrite and gypsum are
indicated in tables 17 and 18.
Euhedral and slighty corroded anhydrite crystals often have a corrosion
direction perpendicular to the crystal's lenght (001 cleavage), while the corrosion direction of olivine crystals is often parallel to the lenght of crystals (010
cleavage).
The original olivine crystals in basaltic material are not or only slyghtly
corroded by magmatic action, however, iron-coatings can be present already
in the original material. Magmatically corroded grains will more easily
weather as is proved by the abundance of iron-coatings, in the more weathered
olivine types ; However, iron coatings can be formed during soil formation from
the olivine grains also; this will be subordinate under present conditions.
74
olivine
anhydrite
gypsum
Fig. 14. Crystal habit of olivine, anhydrite and gypsum in fresh condition or after pretreatment with
hydrogen Superoxide followed by drying at 35° C.
Legend olivine :
1 euhedral (a + b + c)
2 slightly corroded
3 corroded
4 strongly corroded
and coated
5 fragmental
6 rounded
7 penetration twin
1
2
3
4
5
6
7
8
9
10
Legend gypsum :
1 euhedral ( a + b )
2 rectangular
3 slightly corroded ( a + b )
4 denticular
5 strongly corroded ( a + b )
6 fragmental
7 oolitic
euhedral
rectangular
corroded rectangular
strongly corroded
fragmental
oolitic
denticular
corroded denticular
composite sheaf
penetration twin
Table 17. Crystal habit of gypsum in fresh condition without pretreatments
(see fig. 14, legend of gypsum)
Sample
nr
depth
in
cm
30 III
30 IV
30 V
30 VI
23-27
38-42
58-62
83-87
gypsum
% of total fraction 50-500 p.
1
2
3
5
6
7
3,1 2 , 3 2,3
24,4 8,0 6,4 1,3 6,4 48,0
5,2 3,9 48,0 1,3 2 , 6 2 8 , 6
1,2 9,5 2 8 . 6 2 6 , 2 17,8
total %
7,7
94,5
89,6
83,3
Olivine and anhydrite are corroded while gypsum is generally strongly corroded in the topsoil .
The subsoil is characterized by the occurrence of slightly corroded anhydrite
and slightly or strongly corroded gypsum. The content of euhedral olivine is
generally increasing downwards in the soil profile.
The deeper subsoil can have slightly corroded anhydrite and olivine, while
75
ai
Table 18. Crystal habit of easily weatherable minerals after treatment with H O
terrace to volcano and profile 4 of the Volcano province.
Sample
depth
Olivine
%of heavy fraction
in
nr
cm
1
3
3
1I
1 II
1 HI
30-40
45-55
70-80
0,3
7,8
1
1,3
1,0
2,6
1,0
2I
2 II
2 III
5-10
50-60
70-80
5,0
6,5
2,7
5,0
2,4
6,3
8,0
5,6
1,8
3I
3 II
3 III
20-25
80-90
160-170
2,0
3,0
4,0
2,0
6,0
5,0
3,0
1,0
25-35
4,0
9,0
14,0
4I
followed by drying at 35 C of profiles 1, 2 and 3 of the Transitional province from
4
2,4
5
6
0,7
0,3
2,6
4,0
1,6
2,7
3,2
3,6
6,0
,1,0
3,0
3,0
9,0
18,0
20,0
11,0
3,0
3,0
Gypsum
%of light fraction
Anhydrite
% of heavy fraction
1
2
4,0
0,7
1,6
0,9
0,9
1.0
0,6
2,0
3,3
1,0
1,5
4
5
6
7
9
21,4
13,6
12,0
7,5
8,0
4,4
9,2
4,8
1,8
4,9
6,4
2,8
3,5
1,6
11,9
14,0
7,5
2,7
4,0
4,4
4,0
6,6
3,0
2,2
1,0
2,7
12,0
29,0
17,0
9,0
9,6
9,0
9.0
6,4
2,0
4,0
1,0
tr
3
0,9
2, 7 3,8
0,7
Note: The different crystal forms are given in fig. 13.
The denticular types 7 and 8 of anhydrite are abundant in profile 30 (Gypsum province).
0,7
1,0
1.0
2,7
1
2
1,4
1,4
1,4
7,2 1.4
1,2
1,1
1,2
2,3
21,5 1,2
27,9 1,1
1.6
1.0 2 , 0
3
4
2,5
1,4
7
5
6
8,0
9,3
8,6
5,6
21,4
2,5
9,2
16,1
22,2
9,0
12,6
22,4
5,6
1,8
7,0
1,6
5,0
1,0
3,3
gypsum can still be strongly corroded although slightly corroded types dominate.
Fragmental types indicate sedimentation processes and occur in the topsoil or
near the contact of soil layers of different origin, as is the case with sample 2
in.
Profiles 2 and 30 are merging at respectively 65 cm and 35 cm in aeolic
gypsum layers. Near this contact oolitic types of gypsum are abundant as a result of wind action.
However, there are occurences in which the oolitic nature of gypsum is
not related to wind action. In profile 1 there is an accumulation of pedogenetic
gypsum in the deeper subsoil. Oolitic types are abundant, but can come into
being easily by a slight attack of water if the euhedral type lb was the dominant
product of crystallisation. If the edges are dissolved the material will be converted in the oolitic type 7.
.Summarizing it can be stated that there is weathering of minerals in the
topsoil which is low in the subsoil. Slightly corroded material occurs throughout the profile, this being often due to a slight weathering during sedimentation processes. Gypsum is attacked more by the soil solution and even can be
corroded in the deeper subsoil.
Table 19. Weatherability of minerals.
Heavy minerals
weatherability
light minerals
weatherability
garnett
spinel
zoisite+
clinozoisitet
epidote+
hypersthene+
diopside+
augitet
pigeonite+
hornblende+"
oxyhornblendet"
olivine
anhydrite+
low
low
low
quartz
chalcedony
basic volcanic glass+"
orthoclase
albite"
oligoclase+"
andesine+"
labradorite+"
bytownite+"
anorthite+
muscovite"
nepheline"
very low
medium
low
medium
low
medium
medium
medium
low
very high
soluble
gypsum+
calcite+
low
medium
low
low
medium
high
high
very high
very high
low
high
soluble
soluble
77
G
V
T-B-E
^ . Unstable, highly weatherable minerals
Moderately stable minerals
Stable minerais
G
= Gypsum soil 60 - 100 cm
V
= Lapilli soil 60 - 100 cm
T-B-E = Terrace-Balikh-Euphrates soil 0 - 100 cm
Fig. 15. Stability of the mineral content of soil
in the fraction 50 - 500 p,
Between the various mineral provinces, there is a great difference in
weatherability of the soil building material (see fig. 15).
Deep gypsum soil has the highest degree of weatherability with 94% highly
weatherable material. Volcano soil is less weatherable with 14% stable material, while Terrace-, Balikh and Euphrates soils have about 66% stable material,
the rest being mainly moderately stable.
Owing to the mixed quartz content the maturity index can be given according
to Pettijohn (1957) by the ratio ;quartz+chalcedony /feldspar.
The ratio diopside/augite appeared to be highly variable in soil . So did the
ratio epidote/clinozoisite in the Balikh region, due to the young alluvial environment. The ratio epidote/clinozoisite is low in the Euphrates soils, due to
their high content of clinozoisite.
The ratio quartz+chalcedony/feldspar is in Balikh soils about 1, but in Terrace loam soils about lg, pointing to a more advanced stage of weathering of
these soils.
8. CONCLUSIONS
The mineral provinces can be used as a basis for pedological classification, each province giving a unity in mineral composition and age.
The topsoils and upper subsoils have been enriched by wind blown materi78
al, resulting in a certain discontinuity in the soil profile. Below this topsoil
and upper subsoil the mineral assemblage is rather homogenic.
The content of olivine is decreasing with distance from the Volcano province, however there is also a supply from the north as is shown by the olivinebearing Balikh sediment.
The easy weatherable minerals olivine, calcite, anhydrite and gypsum
are common constituents of these soils.
The observed weathering of gypsum and olivine point to a slight chemical
weathering under present soil forming conditions.
The terrace loam soils are more weathered than the younger alluvial of
Balikh and Euphrates.
B. MINERALOGICAL ANALYSES OF THE CLAY FRACTION (<2 p.).
1. METHOD OF ANALYSES
After pretreatment with sodiumacetate pH 5, 30% hydrogen Superoxide and
2 N hydrochloric acid the soil material .$ 50 iiwas dispersed with sodiumpyrophosphate. The clay was collected by décantation of the suspension according
to the Stokes law. The collected material was dried at 100°C and subsequently
ground.
The following specimens were prepared for X-ray diffraction measurements :
a. Powder, orientated at random.
b. Mg-saturated and glycolated, orientation 001.
c. K-saturated and glycolated, orientation 001, heated up to 300°C and 500°C
respectively.
If there was not enough material for preparing powder specimens, the
material was equally spread on a glass slide with the aid of aceton.
Equipment used for X-ray diffraction analysis:
Philips stabilized generator PW 1310 with the wide-angle goniometer PW 1050 and Philips measurement equipment.
Experimental conditions:
X-ray tube Co, radiation Co KB, filter Fc;
high tension 35 kV, current 30 mA;
79
divergence slit 1°, receiving, slit 0, l m m , scatter slit 0,5°:
detector proportional counter. HV (PW 4025) detector 1620 V;
discriminator (PW 4280) LL 280, window 190, attenuation 2 3 ;
ratemeter (PW 1362) range 200, time constant 4;
scanning speed 1° per minute;
chart speed 600 mm per hour;
Bragg angle (2 9 ) 2°-45 .
Quantitative determination by X-ray diffraction:
Determination of clay minerals was done according to the 2 d values given
by (Brown 1961)
A number of standards with different weight ratios of certain clay minerals were compared. The intensity of characteristic reflections were measured
in order tot construct intensity-mineral percentage graphs, (see fig. 16).
IP
IK
Fig. 16. Intensity-mineral percentage graph of ratio palygorskite/kaolite.
I /I = Intensity palygorskite 10,4 A reflection in cms/intensity kaolite
7,15 A reflection in cms.
%P/%K = Ratio weighted percentage palygorskite/weighted percentage kaolite.
a.
b.
c.
d.
80
Short description of method:
Measurement of intensities of characteristic reflections in cms.
Calculation of ratios of intensities comparable with those of the intensitymineral percentage graphs.
Reading of ratios of percentages from the intensity-mineral percentage
graphs.
Calculation of percentage of minerals expressed in one mineral from the
different percentage ratios e.g. ratios P/K,K/Mo,I/K etc. can be expressed
as %P=x. %K e t c . (for abbreviations; see below).
e . Multiplying x. %K by 100/total K gives the percentages of the different c o m ponents .
P r o b l e m s encountered in the quantitative determination a r e discussed below.
Chlorite and montmorillonite giving many reflections between 10-15 A
w e r e determined bij measuring the total peak a r e a of these reflections. The
total a r e a was compared with the kaolinite reflection and expressed in c m s intensity. The samples w e r e heated up to 300 C and 500 C respectively in o r d e r
to get an idea about the content of these two m i n e r a l s separately.
The palygorskite* 10,4 A and illite 1 0 , 1 A reflections a r e usually not to
be separated due to the weak intensity of the illite line. Measurement of p a l y g o r s kite and illite was consequently only possible on the weak 5,4 A and 4,96 A r e flections respectively.
Examination of p u r e palygorskite and illite showed that the intensity ratios
P 1 0 , 4 / P 5,4 and illite 10, l / i l l i t e 4, 96 w e r e respectively 10 and 4 .
Therefore the intensities of palygorskite and illite could be calculated from
the 5,4 A and 4, 96 A reflections and checked by the total intensity of the 10,4
A reflection. The result was reasonably a c c u r a t e .
The choice of a place for m e a s u r e m e n t of intensity does not appear to be
simple. Examination of pure samples and mixtures of these is n e c e s s a r y to o b tain data of the influence of different m i n e r a l s on the intensity of reflection.
The content of clay m i n e r a l s has been indicated by the notation:
no notation
0-10%
+
10 - 30%
++
30 - 50%
+++
50 - 70%
Quartz and feldspar o c c u r r e d in subordinate amounts and w e r e indicated also.
The symbols used in the tables for indication of m i n e r a l s of the clay f r a c tion a r e as follows: Mo=montmorillonite+mixed layer illite-montmorillonite,
Chl=chlorite, P=palygorskite, I=illite, K=kaolinite, Q=quartz and F=feldspar.
2. MINERALOGICAL COMPOSITION OF THE CLAY FRACTION
The same regions as determined by heavy mineral research of the sand
fraction 50-500 \i were examined for the clay fraction.
* Ssaftchenkov (1862; quoted by Milner 1962) first used the name palygorskite after the name of a
mining district in the Urals. Milner prefers to use this name more than attapulgite given by de Lapparent in 1935, who thought these were different from them.
81
The clay mineral composition of the different regions is fairly uniform
due to the mixing influence of the brown loams of the Terrace region.
Illite is the dominant mineral, followed by palygorskite and there are low
amounts of montmorillonite, chlorite and kaolinite.
The gypsiferous material has no components that give rise to new types
of clays. In these deposits there is an admixture of the same clay mineral a s semblage as that of the brown loams.
Table 20. Clay mineral composition of the different regions.
region
Balikh
Euphrates
Gypsum
Raqqa Terr.
Harnret Terr.
Trans. Terr.-Vole.
Volcano
nr
soil
depth
in cm
37 II
IV
15 I
IV
20 II
IV
30 III
VI
24 II
IV
5 II
IV
31 I
V
16 I
III
21
70
6
95
32
88
25
85
12
75
20
80
2
82
2
65
sample
clay minerals
Mo
Chl +
Mo Chi
Mo Chi
Mo Chi
Mo + *CM*
Mo + 'f C h l +
Mo Chi
Chi
Mo Chi
Mo Chi
Mo + Chi
Mo Chi
Mo + Chi
Mo
Chi
Mo + CM
Mo + Chi
K
P++ +
K+
+++
P I
K
P + 1 + + K+
K+
P 1+
+
P 1
K
P + 1+ + K
++ + +
P 1
K
P++
P++ ]
K
+++
P
K+
P 1+ + + K +
P+ *
K+
P+ + + K
P
K+
P+ + + K+
Z K+
Q F
0 F
0 F
Q F
0 F
Q F
0 F
Q F
QH',F
0 F
Q F
Q F
0 F
Q F
Q F
0 F
The Euphrates region has a clay mineral assemblage typically different
of that of the brown loams, having a higher content of montmorillonite and
chlorite and consequently a lower content of illite and palygorskite.
As for new formation of clay minerals after deposition it appears that the
content of montmorillonite has increased in the topsoil, owing to a thorough
wetting of the upper 30 cm after winter rains. It will have been formed at the
cost of palygorskite.The percentage of illite in soils of the Balikh region is
higher in the upper than in the lower part of soil. It seems likely that new formation of this mineral took place.
The chemical conditions necessary for these new formations are fulfilled
by the chemical characteristics of the soil profile.
Higher pH-values, being typical for arid regions, together with higher
82
concentrations of magnesium and calcium will led to the formation of montmorillonites.
If beside calcium ions also potassium ions are abundant illites will be formed.
The mineral provinces determined by heavy mineral research generally
have a similar clay mineral assemblage. Only the Euphrates Province has a
different assemblage as compared with the other regions.
This is caused by the hardly advanced stage of weathering of the soil profiles under prevailing arid climatic conditions and in some cases by the nature
of the parent material.
C. MINERALOGICAL ANALYSES OF THE SILT FRACTION.
A study of the silt fraction together with that of clay and sand fraction is
necessary to get information about the distribution of minerals over the different fractions.
The silt fraction was examined by X-ray diffraction; determination a c cording to the X-ray powder data file (1962).
The results are given in table 21. The mineralogical composition of the
clay and sand fraction is indicated too.
Description of mineralogical composition of the silt fraction in the different regions is given below.
Hamret Terrace, Raqqa Terrace and Balikh region.
The fine silt fraction 5-10 p. has a high content of clay minerals while
the medium silt fraction 20-30 ^ is rich in micas.
Montmorillonite and chlorite occur in the medium silt fraction.
The sand fraction is composed mainly of quartz and feldspar, the amount
of which is gradually decreasing into the finer fractions.
Euphrates region.
The silt fraction has a relatively high content of chlorite. Mica is abundant in the sand fraction.
Volcano region.
Chlorite, montmorillonite and kaolinite occur in the fine-medium silt
fractions. The augite content is relatively high in the fine sand and coarse
silt fractions. Olivine is the most abundant mineral of the sand fraction.
83
Table 21. Mineralogical composition of clay, silt and sand fraction.
Sample
depth in
cm
Region
5I
5 II
5 III
5 IV
0-8
15-25
40-50
75-85
Hamret
terrace
15 I
15 II
15 III
15 IV
0-12
15-25
40-50
90-100
Balikh
Sample
nr
Sample
depth in
cm
Region
24 HI
24 IV
20 II
20 IV
15-43
71-79
30-35
85-90
Raqqa
terrace
Euphrates
0-4
Volcano
Sample
nr
161
Mineralogical composition of clay, silt and sand fraction.
<2p,
Mo +
Mo +
Mo
Mo
Mo
Mo
Mo
Mo
5-10 p,
Chl P I + + + K + Q
Chl P I + + + K + Q
Chl
I + + + K+ Q
Chl
I+++K+Q
Chl
Chl
Chl
Chl
I+++
I+++
I++
I++
P
P+
P*
P+
K
K+
K+
K+
Qx
Q
Q
Q
F
F
F
F
Mo
Mo
Mo
Mo
Chl
Chl
Chl
Chl
P I + + + K Q+ F
P I++ K Q+ F
I* + *K Q + F
I+++K Q F
Mo
F
F
F
F
Mo
Mo
Mo
Mo
Chl +
Chl +
Chl +
Chl +
P+
P+
P+
P+
Mo
Mo
Mo
Mo
<2H
Mo
Mo
Mo + +
Mo + +
P
Abbreviations: Mo =Montmorillonite
Chl=Chlorite
P =Palygorskite
I =Illite
K =Kaolonite
M =Mica
K+
K+
K+
K+
Q
O
Q
O
2-50 H.
Chl P + I + + K +
Chl P + + I + + K
Chl +
I+ K+
Chl + P
I+ K
Mo + Chl
1++
I++
I++
I++
Q
Q
Q
Q
F
F
F
F
Chl +
IMK Q
Chl++ P I
K+ Q+
Chl++ M
K O
Chl++ M
K Q
I + + K+ Q F
50-500 p,
20-30 |i
F
F
F
F
Mo
Mo
M + + + K Q+ F
M+++K Q+F+
Mo
M
++JK
Q+F
M+++ K Q F
Chl
Chl
Chl
Chl
M+++
M+++
M++
M+++
K
K
K
K
Q
Q+
Q+
Q+
F
F
F+
F+
++ ++
F g e
Q.. F g <=
Q F++ g e
Q
F
e
50-500 p,
10-50 p.
Q F
Z I
F
F
F
F+
++
Chl M K Q F + a +
Q =Quartz
F ^Feldspar
Q
g =garnet
e =epidote+clinozoisite
a =augite+diopside
h =hornblende
o =olivine
v =volcanic glass
Q F
Q+ F + M+
Q ++ F + M+
+ +
Qv F
ea h
e
e
e
e
ah
ah
ah
++
a ho
Gypsum region.
Fresh material was examined by a microscope. The silt fraction contained
gypsum and calcite. About 10% of the fraction smaller than 50 M. consisted of
clay < 2 | i .
D. MINERALOGICAL ANALYSES OF SOURCE ROCKS FOR THE SOIL MINERALS.
The state of weathering from soil minerals can only be estimated if the
history of the soil building materials is fully understood.
1. ORIGIN OF THE BROWN LOAM
Tertiairy limestones and marls were treated with 1 N-HC1 until, all lime
was dissolved.
The residue smaller, than 50 p. was examined by X-ray diffraction. The
residue larger than 50 M- was examined by a microscope and some samples
were separated in a heavy and light sand fraction.
The results are given in tables 22 and 23.
Table 22. Mineralogical composition of the residue <50 p, from Tertiairy marls and limestones.
Sample
number
lithology
VII '
m. Lst
cl. marl
I
IV
V
VIII
IXX
XXII
XXIII
XXV
XXVI
VI
XXVII
II
HI
XX
XXI
Lst
Lst
marl-Lst
m. Lst
m. Lst
Lst
Lst
Lst
marl-Lst
marl-Lst
marl-Lst
Lst
chalk
Lst
geological
<50n
age
weighted
7oof
total
rock
Pliocene
Miocene
Miocene
Miocene
Miocene
Miocene
Miocene
Miocene
Miocene
Miocene
Oligocène
Oligocène
Eocene
Eocene
Eocene
Eocene
9,4
0,2
0,4
65,0
0,04
3,8
3,9
0,2
0,4
2,8
16,1
5,8
14,3
0,03
3,8
2,6
>50p.
weighted
%of
total
rock
0,0
•
4,3
22,4
22,6
n. m .
2,3
5,6
4,0
0,02
0,2
0,2
0,1
n.m.
2,8
1,4
0,1
mineralogica: composition
residue < 50 p,
P " 1
P + 1+ + +
Chl + P ] + +
If
Chi P 1
P++
P+ + + +
Mo
++
**
Chi P
++ ++
Chi P
++ ++
Chi P
P** + +
Mo
P+ + +
P**
++
P+
Mo*
Chi P+ + + + +
P++
Chi
Mo
K
K
K
K
K
K
K
K
K
K
K
Q
Q
Q
Q*
F
F
F
F
Q+
F
•
Q F
QI F
F
Q F
Q+ F
Q F
F
"
Q+ F
K Q F
Q"1" b
K Q F
II K °-
p+++r
Abbreviations: m=marly, cl=clayey; Lst=limestone.
85
Table 23. Heavy minerals of the Tertiairy residue and of brown loam near Tuwal al Aba.
Sample
1
1
1
Nr
age
and
% light
min. of
total
residue
2
12
5
6
4
21
24
24
28
1
9
10
1
1
8
11
5
4
5
19
30
7
1
6
24
16
8
5
7
19
11
1
6
6
1
1
1
1
Muscovite
2
tr
9
Accessories
tr
2
1
Saussurite
6
2
22
Alterite
3 1
4 tr
17
Glaucophane
33
37
8
Oxy -hornblei
0,1
0,1
| Green hornbl
Brown hornbl
1,6
0,8
Clinopyroxen
36 I
36 II
1 Titano-augit
2
s
Epidote
Hypersthene
1
cu
Clinozoisite
7
<u
u
Zoisite
tr
Chloritoid
tr
Kyanite
36
Brookite
0,05
I Staurolite
Spinel
0,5
Rutile
Garnet
•
Tuwal al Aba
35 I
0-10
0-10
30-40
n
1
% heavy
min.
of soil
< 2 mm
Tourmaline
% light
min.
of soil
< 2 mm
Zircon
depth
in
cm
Opaque
nr.
Transparent heavy minerals in mutual percentages
6
5
2
7
3
1
1
1
12
6
4
3
15
1
7
<u
c
>
3
4
1
1
% heavy
min. of
total
residue
lithology
XXVI
Pliocene
m. Lst
Miocene
cl. marl
Miocene
m. Lst
Miocene
III
Eocene
VII
I
IXX
Lst
Lst
1,4
0.1
54
1
8
0,1
0,001
28
4
16
6
1
28,9
0,04
68
24
4
9
25
24,3
0,1
42
7
9
1
44,0
0,1
69
24
For abbreviations one is referred to table 22.
7
8
3 12
20
1
3
3
1
3
1
8
1
4
2
2
7
2
7
1
16
4
1
4
7
9
4
There is a striking resemblance between the mineralogical composition
of the Tertiairy residues as compared with the brown loams of the Balikh Basin
(Terrace-Balikh province), as described in section B and A of this chapter.
Palygorskite and illite are the dominant minerals of the clay fraction in
the Tertiairy residue as well as in the loams of the Balikh Basin.
The Tertiairy residue has a heavy mineral assemblage (table 23) which
taken as a whole, is quite similar to that of the brown loams, having a high content
of garnet, clinozoisite, epidote, hornblende and pyroxene. The content of zircon and rutile is higher in the Tertiairy residue than in the loam.
Olivine was found in sample V.
The most abundant minerals of the light fraction are quartz, chalcedony,
feldspar and muscovite.
The evidence obtained by comparison of the mineralogical composition
makes it likely that the Tertiairy marls and limestone served as parent material for the Holocene loam cover.
Weathering of these Tertiairy sediments took place most probably in
Pleistocene times. Lime largely was dissolved and transported by the Euphrates
and tributaries to the sea leaving behind a residue, of which in the course of
time the sand/clay ratio increased due to some transport of clay by fluviatile
action.
During the semiarid climate in Post-Pleistocene times aeolic action started to have a minor influence on sedimentation processes. The result of the increased wind action was a rather uniform thin cover of loam on the PleistoceneTertiairy substrata; uniformity as for the homogenic mineral assemblage due
to the high sorting effect of wind action and the thickness of the deposit.
The content of alterite and saussurite in the Tertiairy residue is about the
same as that of the loam. Clinozoisite and epidote are in a rather weathered
condition. The quartz and feldspar grains have an angular appearance and are
slightly etched. The content of opaque minerals is rather high in the Tertiairy
residues. Since the appearance of minerals in the parent material is nearly
similar to that of the minerals after deposition, it may be concluded that weathering was low after deposition.
The loam cover has the same mineral assemblage over great distances, as
is proved by analyses of some samples near Tuwal al Aba (NW of the Balikh
Basin). Analyses of the heavy minerals are given in table 23.
87
The statements made about origin of the loam cover will be applicable to
a great part of Syria.
2. ORIGIN OF CLAY IN THE GYPSUM DEPOSITS
The gypsum deposits east of the Balikh have in the deeper subsoil an admixture of clay occuring as:
a. thick layers impregnated with gypsum
b. horizons with clay balls
c. horizons with small clay blocks
Some clay balls were examined by X-ray diffraction and compared with
Pliocene clay. The results are given in table 24.
Table 24. Mineralogical composition of colluvial clay in gypsum deposits and
Pliocene clay.
Sample
nr
IXXX
XXX
XXXI
XXXII
XXVIII
Lithology
Coll . clay
COU . clay
Coll . clay
clay
clay
age
Pleistocene
Pleistocene
Pleistocene
Pliocene
Pliocene
mineralogical composition
Chi
Chi
Chl ++
Chl+
Chl+
P+
P1
P
P
P
I
+
i 'K
M'
I
I '
F C+ G
Q F C G
0 F c'
Q F c G A
0 F c G' A'
0
Note: no pretreatments
Abbreviations: G=gypsum; C=calcite; A=ankerite(dolomitic); Coll=colluvial.
The minerai assemblage of the clay from the aeolic gypsum deposit is
rather similar to that of the Pliocene clay. Most probably the Pliocene clay
was eroded in Pleistocene times and deposited on the sandy Miocene erosion
products. However, the proluvial clay could also have originated from clayey
layers of the Miocene. In Post-Pleistocence times the proluvial gypsum sand
was redeposited several times by wind action. Therefore clay accumulations
were only found in the deeper subsoil, the upper part of soil being purely aeolic.
The accumulation of clay balls can be the result from a short transport
of clay eroded from higher situated clay layers. The same holds for the occurrence of clay blocks.
3 . MINERALOGICAL COMPOSITION OF THE HOLOCENE BASALT
Basalt of the volcano Mankhar Gharbi was examined by X-ray diffraction
88
and microscope and constisted of volcanic glass, augite, forsterite and nepheline.
The lapilli can be cemented by lime and gypsum or are not cemented.
They are built up by volcanic glass, forsterite, augite, magnetite, nepheline and leucite. The volcanic glass is opaque due to inclusions of augite and olivine microlites. Without inclusions it generally has a brown or light greenish
colour. Nepheline was found in the sand fraction 50-500 ^ only in subordinate
amounts but lapilli grains contain about ten percent of this mineral.
E. SUMMARY.
Brown loam with a thickness of a few meters or more was encountered in
the Terrace-Balikh region. A loam cover was found in topsoils of Volcano and
Gypsum provinces but was lacking on top of the young alluvial of the Euphrates.
The average heavy mineral composition of the four main provinces is given
in table 25. The subsoil is taken for this purpose because of its intermediate
composition in having often aeolic supply of loam in the original material.
The sand fraction of brown loam is rich in quartz and feldspar while olivine and volcanic glass are the main components of sand from the Volcano
province.
Gypsum sand is composed for more than 90 percent of gypsum.
The average mineralogical composition of the clay fraction is Mo, Chi,
+
p , l + + , Q, F, except for the Euphrates province being Mo , Chi, P, I , Q
F (for notations see section B, 1).
The fine silt fraction was found to be rich in clay minerals. The course
silt fraction was found to have a composition comparable with the sand fraction
except for the Volcano province where augite was more abundant in the silt
fraction than in the sand fraction.
Tertiairy sediments have served as parent materials for the brown loams
which can be regarded as their insoluble residue.
The proluvial gypsum deposits are characterized by the occurence of clay
which minéralogie ally resembles Pliocene and Miocene clay.
In the fine earth of lapilli loam soils, nepheline is occuring only in subordinate amounts, but it is a common constituent of coarse lapilli.
89
Table 25a. Average heavy mineral composition of the subsoil from the main m i n eral provinces.
90
23
13
14
7
26
13
8
9
1
3
57
3
Alterite+sauss urit
13
27
7
13
31
1
12
7
9
in
Other minera
20
18
6
8
Anhydrite
Olivine
2
Amphibole
5
3
Pyroxene
3
6
1
6
Epidote
9
36
26
50
Clinozoisite
Zoisite
Euphrates province
Terrace-Balikh province
Volcano province
Gypsum province
Garnet
REGION
Opaque
Transparent heavy minerals in mutual
percentages
8
5
12
C H A P T E R IV
SEDIMENTOLOGY OF THE SOIL MATERIAL
Holocene deposits given in chapter in, A, 2 are discussed below.
Sedimentology of the soil material should be examined thoroughly before
interpreting the soil -forming process.
Therefore, sedimentological characteristics of the main soil-forming materials are discussed and deductions are made about their origin and way of deposition.
For location of the deposits one is referred to the soil map and fig. 11.
1. SEDIMENTOLOGY OF THE BROWN LOAM COVERING THE PLATEAUS
The brown loam of the Balikh Basin was derived from Tertiairy strata as
is shown by comparison of the mineralogical composition of the Tertiairy residue
with that of the brown loam (see chapter HI, D, 1 ) .
There are two different types of brown loamy sediments, namely the alluvial fill of the Balikh valley and the aeolic loamy cover of the plateaus.
The latter will be discussed below.
The maximum thickness of the loam deposits on the Pleistocene terraces
is 270 cm, while the deposit is lacking at the Holocene Euphrates terrace.
Often there is an admixture of gravel derived from outcropping terrace
gravel.
Layered material was not found, but this can easily have been destroyed
by soil fauna since conditions were aerobic for a long time (see chapter I, A,
10).
The texture of the soil profile is quite homogenic in having a clay content
91
of 30-35 percent. Cementation of clay particles due to weathering in the upper
part of soil can be regarded as an important agent enabling transport of clayrich material by wind action. A cementation into clusters of palygorskite in material of the topsoil has been observed (chapter VIII, A, 2).
The time of deposition of these loams will have been during and after the
first stage of formation of the Mankhar volcanoes for the following reasons:
—the top layers of the lapilli deposit are intensively mixed with loam;
—incision of lapilli deposits took place and the valleys formed are often filled
up with several meters of loam which frequently are mixed with lapilli;
—the lapilli-built piles in the crater have an aeolic admixture of loam; these
piles have more recently been formed in a later stage of development when
the climate was more arid.
The first stage of the Mankhar- volcanoes was an explosive one with pyroclastic products and has been dated to be after the formation of the Upper Pleistocene terrace and before the formation of the Holocene terrace.
For reasons discussed above the loam will have been deposited on the terrace at the end of the Upper Pleistocene and in Holocene times.
During pluvial times there will have been a quite luxurious vegetation and
consequently an intensive weathering. The formation of a calcareous soil took
place during the last pluvial. The climate became more arid at the end of the
Upper Pleistocene which led to destroying of the natural vegetation (phase of
Rhexistasy, Erhart 1956). There was an intensive erosion due to the action of
winter rains and during the dry summer of wind.
The terrace "Island" (see chapter H, B) became isolated at the end of the
Upper Pleistocene and is covered locally by more than 200 cm loam. The material will have been deposited by aeolic action since the "Island" had no supply
of drainage water from the north. Therefore, the loams on the Hamret terraces
can be regarded as aeolic deposits too, although there was possibly a greater
supply of fluviatile material.
The climatic conditions during the Holocene had much influence on sedimentation processes. For a description of the Holocene climate one is referred
to chapter I, A, 10.
The arid Preboreal and Boreal with dominant wind action were succeeded
by the moister Atlantic period in which run off processes were abundant which
are responsible for the higher content of gravel in the deeper subsoil.
The topsoil contains a larger amount of grains smaller than 200 [j, as com92
pared with the deeper subsoil what may be due to the intensive aeolic action in
the arid Subboreal and Subatlantic.
2. SEDIMENTOLOGY OF THE SANDY GYPSUM DEPOSITS
A large part of the region is covered by a sandy gypsum deposit with a
thickness of three to eight meters. Locally clay deposits of several meters thick
are intercalated or there is an admixture in the deeper subsoil of clay balls
and/or small clay blocks. A repetition of clay horizons at a distance of four to
five meters from each other was observed at some places. The clay might have
originated from Pliocene and Miocene clay deposits.
Loamy material can be mixed with gypsum in the subsoil when an aeolic
loam cover is present on top of the soil profile.
The hypothesis that such deposits are the weathering products of lagunaire
gypsum in situ will not hold for the following reasons.
The Miocene gypsum was deposited in a lacustrine facies on a sea bottom
with irregular topography. Submarine depressions between marls, limestones
and sandstones were filled up with gypsum and consequently these deposits
are not extensive.
This is in contrast with the sandy gypsum deposits of the region which cover
without interruption a vaste area.
These deposits are overlain by Lower Pleistocene gravels and therefore
are older. Deposition will have found place at the start of the Quarternary and
must be related to the rising of the Tuwal al Aba anticline with Miocene gypsum
deposits which upon weathering gave rise to a supply of angular gypsum grains.
A mantle of gypsum debris was found to surround the anticlinal uplifts.
The occurrence of clay layers, clay balls or small blocks are indicative
of temporarily wet conditions during transport. However, for gypsum, wind action may have been an important transporting agent.
The deposit is considered to be proluvial because it is lying near to his
source region.
During the Pleistocene this sandy gypsum deposit was dissected intensively and some gypsum sand was transported to the lower lying terraces.
The upper 60 cm of soil are generally free of clay due to aeolic action on
this surface layer during arid periods of the Pleistocene and Holocene. Gypsiferous deposits have been protected against such erosion by the formation of a
crust.
93
3. SEDIMENTOLOGICAL CHARACTERISTICS OF THE OTHER SOIL MATERIALS
The Balikh alluvial is built up of brown loams and clays originating from
the Tertiairy residue (chapter m , D). Locally a platy fabric was observed derived from fluviatile action.
The Euphrates alluvial is built up of sediments with varying texture and
a platy fabric is often present. Irrigation water loaded with sediment particles
has locally led to deposition of a loamy to clayey top layer of several centimeters .
The lapilli has an admixture of about 25 percent of grains larger than 2
mm. Generally these have a size of 2-4 mm, but 4-8 mm does occur also.
4. SOME OBSERVATIONS ABOUT SEDIMENTATION DURING AND AFTER A SAND-DUST STORM
A storm started during the night, became very intensive at about nine hours
in the morning (11-12-1965); direction of wind from east to west.
Some samples were collected in the Gypsum and Hamret region.
The samples 48 and 49 were taken during the storm near the village of
Mai'zile and 50 after the storm near Hamret Butiya; 48 was collected with a
disc of 40 cm diameter placed vertically above the soil surface; 49 and 50 were
taken in small depressions . With the disc 500 grams of soil were collected in
only one hour. Small wind ripple marks were present in the just deposited material in depressions.
Table 25. Texture data of aeolic material accumulated during and immediately after a dust-storm.
Region
Gypsum
Hamret terrace
sample
texture
> 5 0 1 M- 50-20u <2\i.
no
48
49
50
87, 1
92, 6
73, 7
2,6
5,4
25,3
10, 3
2, 0
1, 0
%
C
0,36
-
0,50
)
%
CaCO3
Gypsum
28, 5
22, 5
23, 7
6,46
1,42
tr
The data of table 25 show that an admixture of 10% clay in the aeolic material is possible. This will be due to cementation of the clay particles and
rounding of these aggregates. The percentage of carbon points to a large contribution of topsoil material.
In the Gypsum region the percentage of gypsum is relatively low, due to
the angularity of the gypsum grains and the mantle of aeolic loam covering the
94
gypsum deposits.
The occurrence of dust-storms as related to climate is discussed in section A, 6 of chapter I.
95
CHAPTER V
FLORA AND FAUNA
Flora and fauna in relation to climate, soil and topography are discussed
below. The different plant species found in the Euphrates-Balikh region are presented in table 26 and the location of the sample areas in fig. 18.
Plants took up silica from the soil as is proved by the occurrence of phytoliths. They are discussed in section A, 4.
A. F l o r a of t h e E u p h r a t e s - B a l i k h
Basin.
The Euphrates-Balikh Basin belongs to the Irano-Turonian phytogeographic
region. E.R. Guest (1966) considers the family of the Chenopodiaceae characteristic for the region. Certainother groups like Astragalus and Salvia are always present.
1 . EFFECT OF CLIMATE ON VEGETATION.
Climatic factors largely determine the general aspect of the vegetation.
The climate of the Euphrates-Balikh Basin is characterised by dry, hot
summers and relatively cool winters. January with a relatively high amount of
rainfall has an average temperature of approximately 6°C. Therefore, rainfall
of the winterperiod cannot be used optimaly by the vegetation because of the
too low temperature.
The main growing season is from March to April with some rainfall and
more favourable temperatures. This short period in which growing of plants is
possible gives rise to a semi-desert vegetation although the general aspect of
96
the climate is arid (see chapter [).
If there is sufficient rainfall the desert can be converted at spring time
from a grey-brown dead surface into a green grassland with numerous bulbs
and poppies. During the long summer there is no surface water available and
the intense heat and dryness of the air create conditions of extreme desiccation.
The moisture content of soil drops far below wilting point (chapter I, B, 2).
Ephemeral annuals are able to survive such unfavourable conditions. They rapidly complete their life cycle in spring time and then lie dormant in the form of
seeds.
Distribution of seed over very large areas is made possible by wind action, taking seeds with it in wind-blown clayey balls (Simons 1967).
Most perennial plants are shrubs and occur at places where there is more
moisture e.g. in depressions and wadis. Their roots draw in water from considerable depth and from a wide area round about. They are spaced meters apart
owing to the small amount of water available. Their leaves often have spines
and are rolled. Stem and branches are woody and tough andhave no water storage
tissue.
Some desert perennials obtain moisture from night dew but this effect will
be very low in summer.
3*f'
Fig. 17. Semi-desert vegetation of the Balikh Basin.
97
Deserts, semi-deserts and steppes are distinguished from one another by
differences in the physiognomy and the structure of their vegetation, that is,
the different degree of coverage is the decisive factor.
The semi-desert of the Euphrates-Balikh Basin may support cultivation in
the period March-April and provides grazing in all seasons, though it is often
bad grazing.
A true desert is territory so devoid of vegetation that it cannot provide appreciable grazing and dry farming is not possible.
2 . EFFECT OF SOIL AND TOPOGRAPHY ON VEGETATION.
The Tertiairy residual material (brown loam) is transported by fluviatile
and aeolic action and covers most of the deposits, or is mixed with them, except
for the Euphrates alluvial. Therefore, the influence of different lithology is masked.
The vegetation of the brown loam consists of a uniform shallow rooting
grass cover, and locally shrubs are found.
Plants have in common that they are calciphyles due to the highly calcareous soils with high pH.
Even quite small amounts of salt in the soil may prohibit the occurrence of
many plant species, for:
a. it causes osmotic troubles for the plants;
b. it forms often a relatively hard crust at the soil surface;
c. it decreases the volume of pores in the soil.
Saline soils occur in the Euphrates valley and locally in depressions of the
Terrace and Volcano regions. Lapilli-containing soils of the Volcano region
generally have an excess of exchangeable sodium and consequently have a poor
structure.
Gypsum soils occur over a wide area. For most plants growth will be r e duced when the gypsum content is above 25 percent (Smith and Robertson 1962,
Van Alphen 1968).
For the greater part of the year there is a sharp contrast in colour between
the greyish-brown plateau and the green Euphrates valley.
Valleys on the plateau lands are generally filled with loam, have more moisture and therefore their own characteristic type of vegetation; bulbs are more commo.
and they have more grass than their surroundings.
I
Perennial shrubs are numerous in the Balikh valley where soils have a
98
higher content of moisture.
Trees occur in the Northern Balikh valley a t Ain Arus and in the Euphrates valley where roots can reach the groundwater.
Edaphic desert is found on highly saline soils and on flat impervious soils
and rocks.
Agricultural activity leaves the patches used,nearly bare. Wind erosion is
quite severe during the summer at such places and microdunes are formed.
3 . VEGETATION OF THE DIFFERENT REGIONS.
Plant species were collected in different regions according to their abundancy be it that some small areas were sampled as a whole.
The plants were identified by Mrs. T. Baretta of the Institute for systematic Botany at Utrecht (Netherlands) and are shown in table 26. Orders, families and species are arranged alphabetically.
The number of plants taken will not be- sufficient for determining the different associations but a least they give an impression of what can be expected.
The location of the sample areas is given in fig. 18.
Only a few plant species were collected in the regions 5,8, 9 and 10. These
are not indicated in table 26 but are given in the text.
Theregionsl and 2, and the southern part of region 3 belong to the Euphrates,
region (fig. 18). This region is characterized by a great number of weeds and
halophylous plants due to irrigated culture. Halophylousplants like Suaeda baccata occur on the sides of irrigation channels and on saline agricultural patches.
Many shrubs are found in the flood plain.
The Balikh (eastern part of region 7) is cultivated and many shrubs are
found (see table 26); ploughing prevents the development of a grass cover.
Cephalaria syriaca (L.) Schrad (fam. Dipsaceae) was found in the northern Balikh region (8).
Gramineae (or Poaleae) e.g. Koeleria phleoides are the most abundant
plants of the plateau lands. The characteristics of the different plateau regions
are given below.
Region 4 and 5, and the western part of region 7 belong to the Gypsum
region with shallow loam soils on gypsum sand. Valleys are generally filled
with loam and the tops of hills are composed of nearly pure gypsum sand, often
encrusted at the surface. The vegetation of gypsiferous soils is characterized
by the occurrence of Achillea santolina, Launea spinosa and Ziziphora tenuior.
99
TABLE 26i PLAflTS 0? THE EUPHRATES-BALIKH BASIH •
|
faaily
Apiaeaaa
Aataralaa
Aatarao«**
Braaaioalaa
BrasBlaacea«
Carjopbjllalas
Papavar**««*
Basadaoasa
Caryophy1laoaaa
Cbsnopodlacaas
Clvt&laa
Oaranialaa
Taaarioaoama
Oaraaiaeaa*
LlliBl«B
Irldaoaa*
Llliaea««
PlsJit*gln»l*s
Plantaginaoaaa
Poalaa
Poaoaaa
Polygonal*a
Priaulalaa
Bamiaeulalaa
Polygon»«aaa
Priaulaeaaa
Banunoulaoaaa
Soaalaa
fsbacaa«
Rutalaa
Butaoaaa
Solanalaa
Bor«glnaoa&«
C onTolvulacaaa
Laaiaoaaa
Thymlaaalsa
100
Ox-obanohacsfta
Soropbular iaoaaa
Solanacasa
Blsagnaesaa
Koracaaa
apaciaa
Buplaurua glauoua Hobill A Caat ax D.C.
Cauoalia taoalla Dal.
Hippoaaxantbna boiaalari Baat. A Hauak.ax Boisa.
Achill»» saatollna L.
Artaalala barba-alba Aaao
Bvax «natolie* Bolaa. at Haldr.
Oundali» tournsfortil L.
Koslpinla llnawia Pali
Lauasa apiaoa» (Porsk) Scb. bip.
Laoatodoa arabloua Boiaa.
Matrioaxi» auraa (Loafl) Sob. bip.
Katrioaria ebaaoallla L.
Saaaoio ooronopifolius Dsaf.
Alyaaua aaaioooidaa Boiaa.
Arabldopaia puaila (Stapb.) Buacb.
Caps*11a buraa-pastoris (L.) Madik.
Daseurainia aopbU (L. ) Prantl.
Dlplotaxla acria (rorsk.) Boiaa.
Dlplotaxla oruooidaa (Tornar) D.C.
Lspidiua draba L.
MalcolaU afrieana (L. ) B.Br.
Maloolaia «raaaria D.C.
Maleolaia toruloaa (Dasf.)
Boiaa.
Moricandia nitana (Tiv.)>Dur. A Bart.
SiajBbrlua irio L.
Siayabriua scbiapari Boiaa.
Slayabriua aaptulatus D.C.
Starigaostaau» sulpburaua (Banks A Solaadar) Borna.
Hypaooua proouabana l>.
Rassda lutaola L.
Biantbua Bultipunetalua Sar.
Xiauartia picta (Slbtb at SaJ Borna.
Silana coniflora Vaaa ax Ottb.
Spargula pantaadra L.
Spargulari* diaadra (Ouaa) Haldr. •* Sart.
Salsola Till OM Dal.
Suaada baceata Fbraak. ax 3.V. Osai.
Taaarix tatandra Ouabb* «x Bunga
Erodiua oiconiua (L.) L'Har.
Erodlua oioutariua (L.) L'Har.
Srodlua Bosoaatua (L.) L'fiar.
Croous spac.
Kusc«ria longicapa Boiaa.
Kusoaria ntcaaosua (L.) Mill.
Plaatago notât* Lag.
Plant*go ovata Forak.
Alopaourua Byoauroids» Buda.
KoalarU pnlaoidaa (Till.) Para.
Polygonua «Ticular* L.
Androaaoa r'Tlai L.
Adonis aaativmlia L.
Adonia autuanalia L.
Adoaia palaastin« Boisa.
Caratooapbsl« falcata (L.) Para.
Albasl aaurorua Madik.
Astragklus ruasallii Banks «t Solandar
lUdioago polyaorpha L.
Onobrychu« orist*-gall1 (L.) Laa.
Ornithopua ooaprsasua L.
7ioi* palasstin« Bol*»«
Haplophjllua buxbauaii (Polr.) Boiaa.
Haplophyllua loagifoliua Bolaa.
Arnsbi« dacunbana (Ta&t.) Coaa. «t Eral.
ConTolvulus piloMllifoliua Baar.
Convolvulus Btaohjdifoliua Choisy
Crass« oratie« L.
S«lvi« pal«*atin* Baatb.
Salvia apinos« L.
Taucriua pollua vas albua (Mill.) Florl
Ziaipbora tanuior L.
Ciataacba salaa (C.A.May) 0. Back
Taroaio« dldyma Tan.
Lyoiua arabieun Scbwainf.
Sla«gnua auguatifolica L.
Norua alba L.
1
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3
4
6
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traa
waad
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ordar
Apialaa
son.
PLAR
PE0PEHTIE3
BEOIC*
PLABT
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PBOPsrrn
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Fig. 18. Location of the sample areas for vegetation survey in the Euphrates-Balikh Basin.
Legend:
1. Western Euphrates region.
2. Eastern Euphrates region.
3. Volcano-Euphrates region.
4. Gypsum region with terrace gravel.
5. Gypsum region.
6. Tributary of Wadi al Fayd.
7. Balikh-Gypsum region.
8. Northern Balikh region.
9. Limestone region.
10. Tuwal al Aba region.
Colchium deserti-syriaci Feinbr. (fam. Liliaceae) was found in some loamy
valleys of region 5.
While the vegetation cover of the deeper loam soils on the Pleistocene terraces is continuous, this is not the case in the volcanic and gypsiferous areas
due to soil deficiencies.
Vegetation of volcanic lapilli soils is characterized by a more scanty appearance and microdunes have developed. Shrubs are more common and plants
generally are more resistant to alkali. Some typical species are Ceratocephala
falcata and Astragalus rusellii.
Loamy valleys of the plateaulands (region 6) are relatively rich in plant
species. Bulbous plants as Muscaria racemosum are common. Many plant species occuring in this valley are also found in the Euphrates valley with other environmental conditions.
Eminium spiculatum Blume Ktze (fam. Araceae) is abundant on shallow
loam soils underlain by limestone (region 9).
101
Gagea chlorantha M.B. (fam..liliaceae) was encountered on gypsiferous
soils near Tuwal al Aba (region 10).
4 . THE OCCURRENCE OF PHYTOLITHS.
Plants take up silica and precipitate it at walls of cells or channels.
The occurrence of small particles of opaline silica in soil derived from
plants has long been recognized by Russian pedologists.
In 1843 Ehrenberg introduced for these opaline particles the name phytolitaria (phytoliths), implying the stony part of the plant.
Most of the phytoliths are found in the fine sand and silt fractions of soil.
The following method of analysis was used:
The fraction 10-210 V of soil was brought into an alcohol-bromoform mixture
with specific gravity of 2,2. Opal has a specific gravity of 2,1 (Milner 1962)
and therefore will float on the liquid. The separation appears to be imperfect
but the lighter fraction thus gained has a high content of phytoliths. This material and some plantrests were studied by a pétrographie al microscope.
Many phytoliths were described by Grob (1896), Netolitzky (1929), Smithson
(1958) and Parfenova, Yarilova (1962). These autors presented types formed in
Gramineae (Poaleae) which show a good resemblance to those found in the r e gion. The forms collected in soil material of the Balikh Basin are shown in fig.
19.
Silica taken up with the soil solution is gradually filling the cells, starting
at the cell wall and growing centripetally. Thus are formed casts of the long
(a,b,c,f) and the short (d,g,h,i,) grass epidermis cells. The protoplasma is
replaced by silica, but there are often bubble-like rests of it in the opaline bodies (d). The surface of the long cell casts is smooth (a) or undulating (c).
Type e has a central channel and probably is a part of a silicified hair.
Table 27 represents for the different regions the relative content of phytoliths which are mainly derived from Gramineae. Types d and g were abundant
in the Euphrates soil and types a and e in the loamy terrace soil.
The content of phytoliths is relatively high in the Euphrates soil and the
topsoils of Volcano and Terrace region. Sample 5 IV probably marks a former
A horizon. A low amount was found in gypsum soil and Balikh alluvial.
Silica goes into solution at the high pH normal in desert soils if enough water is available. Therefore, owing to the low moisture content only subordinate
102
Fig. 19. Forms of pytoliths found in some soil profiles of the Balikh Basin.
Legend: a = long cell cast, smooth surface; b = long cell cast, undulating on one side;
c = long cell cast, undulating on both sides; d = short cell cast; e = hair cast;
f = long cell cast with undulating sides and central channel; g = thick fan shaped bodies; h = small dumbbels; i = small square and rounded rectangular
bodies; j = rod-like body.
Table 27. The occurrence of phytoliths in some soil profiles of the Balikh
Basin.
relative
sample nr
depth in cm
Region
content of
phytoliths
Gypsum region
Balikh region
Euphrates region
Volcano region
Hamret terrace
region
30 I
30 II
30 III
15 I
15 II
15 III
15 IV
20 II
20 III
16 1
16 II
16 III
5 II
5 III
5 IV
0-5
8-13
20-30
0-12
15-25
40-50
90-100
30-35
60-65
0-4
20-30
60-70
15-25
40-50
75-85
note: + relatively low
++ relatively abundant
amounts of silica will be dissolved. However, during the short growing season,
the soil moisture taken up by plants will contain some silica and phytoliths will
be formed.
Some aspects of the effect of phytoliths on the plant are discussed below.
Details about this subject are given by Netolitzky (1929).
The opaline incrustations lower the permeability of the cell wall for water
and solutions with as a consequence a reduced evaporation. They protect the
plant against eating by animals. Pointed leaves have been found often to be silicified at the ends.
103
Some authors (mentioned by Netolitzky) state that the formation of phytoliths is merely a phenomenon of nutritional supply and more or less an unfavourable factor for plant life. However, it cannot be doubted that their presence
is favourable for the firmness of the plant.
B . F a u n a of the E u p h r a t e s - B a l i k h
Basin.
1 . VERTEBRATES.
Herds of sheep, goats and dromedaries move from one pasture to another
and are indispensable for the food management from nomads and villagers.
Animals must be able to withstand the extreme temperatures and absolute
dryness of the summer. Dromedaries are highly specialized to withstand drought
and can survive a waterloss of about one quarter of their total weight. Sheep
store food reserve in their tails during winter and spring time and thus are
able to live on dried grass during summer.
Rodents are small and survive the hottest part of the day in burrows. Some
of these are rabbits, hares, desert rats and porcupines. They obtain moisture
from roots and stems they eat, and can thus go for long periods without drinking. Losses by evaporation and excretion are reduced to an extremely low level.
Some desert rodents spend the hottest months in a state of inactivity.
Foxes are quite numerous ; often they use karst pipes in the gypsum region
as a shelter. Antilopes and wolves are seen occasionally.
Reptiles, chiefly lizards (e.g. arual with a lenght of about 70 cm) and
snakes are rather common. The variable blood temperature enables them to
tolerate desert conditions rather better than warm blooded animals. A reptile
is able to reduce its body temperature and the need for evaporation by burrowing into the ground or seeking shelter beneath rock, it also may obtain liquid
from dew.
The arual is active only in spring time and lies dormant for the rest of the
year in burrows under the ground.
The Euphrates river is rich in fishes. Tortoises, crabs and watersnakes
were found in oxbowlakes of the Euphrates valley while frogs occurred in some
desert pools.
Birds are numerous in the desert at spring time but in summer they stay
near rivers or move to more favourable territories. Partridges, pigeons, larks,
storks, herons, falcons and owls were encountered.
104
2 . SOIL FAUNA.
Insects and arachnida (spiders, scorpions, mites) being more abundant
than earth worms in the desert, are well adapted to the unfavourable environ-,
ment for they,
-require little water,
-can bear extreme temperatures,
-lose little water by evaporation,
-can bury themselves into the soil,
-can spend very long periods in a state of inactivity.
In the light fraction obtained with bromoform-alcohol (specific gravity 2, 2)
also chitine rests of the external skelets of insects and arachnida were met.
Round shell-like bodies with a brown to light brown colour (testaceans) occur in all profiles. They appeared in profiles 20, 16 and 5 in lower amounts,
were more abundant in samples 30 I and n, and very abundant in profile 15. Also the variation of different chitinous skelets was greatest in the latter profile
(the regions in which these profiles occur are given in table 27 ), this being due
to the greater wetness of the Balikh valley. However, in soils of this valley
crotovinas only locally were observed in contrast to the relatively great number
of burrows in the drier terrace loam soils. Apparently the soil fauna influences
soil structure more under dry than under wet conditions.
The chitine rests were examined by Mr. J.H. de Gunst (entomologist,
ITBON, Arnhem, The Netherlands). The results are given below:
Profile 15 of the Balikh region contains fragments and excrements of mites and testaceans;
profile 20 of the Euphrates region contains mites (Acari ; Trombidiformes)
and excrements of insectlarvae;
profile 16 of the Volcano region contains fragments of mites and mandibles of insectlarvae.
Mites, insects and protozoa were found to form the greater part of soil fauna.
The population of bacteria and other micro-fauna will be approximately
proportional to the amount of protozoa.
Earthworms are intolerant of drought and frost (Rüssel 1950). However,
wormcasts were observed in Balikh soil.
105
CHAPTER VI
LAND USE
1. HISTORY OF LAND USE
For details on the history of land use one is referred to Butzer (1961).
The beginnings of agriculture during the Prehistoric period (6000-3000 B.
C.) coincided with the most and warm Atlantic period (see chapter I, A, 10).
The region under consideration was populated at that time, witness the
'tals in the Balikh valley. Flint sickles found on the Euphrates terraces and in
the main valleys point to the cultivation of cereals. These stone objects have
long been used, also when copper and bronze implements appeared.
A beginning of irrigation has been dated to be between 4000 and 3000 B.C.
The early historical desiccation shortly before 2000 B.C. was quite s e vere as conditions were temporarily more arid than at the present time.
Towards the end of the last millenium B.C. (Hellenistic and Roman times)
climatic conditions began to improve again and agriculture was the chief occupation throughout the Fertile Crescent.
In Roman times very much land was under cultivation, supported by the
construction of aqueducts and irrigation works, the rotation of crops and the
apply of organic fertilizers.
During the Byzantine period agricultural activity was greatly reduced
owing to continued inflation and increase in taxation.
Land deterioration became general in the early Arab and Crusader period
(640-1250) followed by Mongol invasions at the end of the 13th century.
Also the Turkish period (1516-1917) was not favourable for a good development of agriculture.
106
At the present day irrigation is practiced where possible supported by government and private investments. Dry farming is a rather risky enterprise because of the irregular and scanty rainfall.
2. FARMING SYSTEM IN THE BALIKH BASIN
For this purpose the region is divided into:
a. Valley l a n d s of E u p h r a t e s and B a l i k h .
A monoculture of irrigated cotton (generally basin irrigation) is practised.
There is a small hectarage of vegetables and irrigated cereals.
The main source of irrigation water is the Euphrates. Water is pumped
from wells at some places along the edge of the higher terraces.
A crop rotation often practised in the Balikh valley in order to prevent diseases and to obtain a better harvest is cotton-fallow-wheat-fallow-cotton.
A crop rotation of cotton and wheat in one year is impossible due to the
long cotton season.
The natural fertility of the soils is low. Therefore, nitrogen and phosphorous must be supplied.
b. P l a t e a u l a n d s .
A semi-nomadic sheep and goat husbandry is an important source of income. There is a limited hectarage of cotton and vegetables. Dry farming of
cereals is practised extensively on the loamy terrace soil and in some broad
valleys of the Gypsum and Volcano region.
107
CHAPTER VII
MAPPING METHODS
1. GENERAL MAPPING METHOD WITH AERIAL PHOTOGRAPHS
Vertical aerial photographs scale 1:8.000 were used and studied with a
stereoscope. The aerial photographs were taken by E.I.R.A. (Florence, Italy)
during the period september-november 1961 when soil conditions were slightly
moist.
After a study of relief features the different tone patterns were used to distinguish expected soil boundaries.
Very light grey shades on the aerial photographs were caused by:
saline efflorescences at the surface;
gypsum and marls at the surface;
plants with a high albedo;
sandy places in the Euphrates soil.
There was a shade contrast of light grey and dark grey between:
loam and gravel;
non-irrigated and irrigated soil;
ridges and sloughs of point bars.
The lapilli deposits were characterised by a striated pattern derived from
wind-formed mega-ripples. This striage is locally disturbed by diffuse run off
patterns.
Soil boundaries were interpreted from the aerial photographs and transferred to photomozaics scale 1:10.000. These photomozaics were used in the
field and the expected soil boundaries were checked; where necessary the aerial
108
photographs were studied again.
Augerings were made to a depth of lm and locally up to 3 m giving an evaluation of the following:
— texture and colour of the soil material;
— the approximate content of lime by the reaction on hydrochloric acid;
— quantity of stones and gravel;
— moisture conditions;
— depth of blockage;
— amount and kind of accumulations and concretions.
When the different soil types were established, pits were dug in the centre
of the most characteristic soil bodies. From each soil pit a detailed soil description was given. Intake rate and occasionally soil temperature were measured and samples were taken in order to obtain data about chemical properties,
permeability, soil moisture , field capacity and occasionally size of aggregates
and aggregate stability.
Soil maps were drawn on a scale 1:10.000 and reduced to 1:50. 000.
2. FIELD CLASSIFICATION SYMBOLS
During fieldwork it appeared to be necessary to express precisely and in
short terms the properties of the soil in a symbol, this being useful not only to
classify the soils in texture groups, but also according to depth, petrology,
stoniness and diagnostic horizons.
A similar system has been applied by many schools of pedologists. The
system used by pedologists of the University of Utrecht (The Netherlands) was
applicated to arid soils and is given below.
Chemical consistence of the soil material is of definite importance for the
properties of the soil profile. The following different petrological groups of
soils were recognisable:
(a) brown calcareous loamy and clayey soils;
(b) grey marly soils ;
(c) Euphrates alluvial soil;
(d) sandy gypsum soils ;
(e) light yellowish brown loamy lapilli soils and grey lapilli;
(f) soils on gravel.
For soils mentioned under a,c and f texture was sufficient to differentiate
109
them. However, for b it appeared sometimes to be necessary to differentiate
between marl, marl powder and blocky marl (colluvial). In group d, geological
gypsum with a gypsum content of about 50-70 percent, and proluvial gypsum
with clay or marl blocks and a gypsum content of more than 25 percent were
recognised. Group c was differentiated according to the content of silt or loam.
A differentiation in A, B and C.soils was used, these having a depth of more
than 60 cm, 30-60 cm and less than 30 cm respectively. The classification of
depth is based on agriculture, 30 cm of soil being the minimum to have a successful crop of cereals and 60 cm of soil for a successful crop of cotton.
The field classification symbol has four or more letters and figures; the first
letter is an indication for the depth of soil, in the second place a figure for the
stoniness, then the texture, and finally indications for the development of the
soil profile. In the case of gypsum and marl soils, it was sufficient to use the
indications of the petrology, such as Ag and Am (see below e).
This system appeared to be very useful to work with and was a basis for
constructing the soil map.
The different notations together with some examples are given below:
a. Depth of soil: A=more than 60 cm; B=30-60 cm; C=0-30 cm.
b. Stoniness:0 =nothing; l=few; 2=medium; 3=rich; 4=very rich.
c. Texture: S=sand; L=loam; Cl=clay
lapilli soils—l=lapilli with particles > 2mm grade 3-4 (see b)
Ll=silty lapilli with particles > 2 mm grade 2-3
lL=lapilli silt with particles > 2 mm grade 1-2
(l)L=loam with few lapilli and particles >2 mm grade 0-1
d. Development of the soil profile: b=lime spots; h=humus particles; r=mottling;
v=vertic; cr=gypsum crust; c=gypsum pockets lower than 60 cm, Cpgypsum
pockets between 30 cm and 60 cm, c =gypsum pockets in the upper 30 cm,
the content of gypsum being lower than 25% ; A , B , C pedological accumuP P p
lated gypsum at depths of 60-100 cm, 30-60 cm and 0-30 cm respectively with
a gypsum content of more than 25%; sa=salt accumulations lower than 60 cm,
sa.=salt accumulations between 30 cm and 60 cm, sa =salt accumulations in
the upper 30 cm.
e. Petrology: Ag, Bg, Cg=geological gypsum with a gypsum content of 60-70 %
or more at a depth of 60-100 cm, 30-60 cm and 0-30 cm respectively; Age,
Bgc, Cgc=colluvial transported gypsum mixed with clay or marl blocks at
depths of 60-100 cm, 30-60 cm and 0-30 cm respectively; Am, Bm, Cm=
soils on marl; Amp, Bmp, Cmp=soils on marl powder; Amc, Bmc, Cmc=
110
soils on colluvial marl at depths of 60-100 cm, 30- 60 cm and 0-30 cm r e spectively.
Examples: AllLb=deep soil, more than 60 cm; stone content few; texture lapilli loam; lime accumulations.
Ag0Lbc=deep soil, more than 60 cm; stone content nothing; texture
loamy; lime, and gypsum accumulations lower than 60 cm;
• lying over geological gypsum between 60 cm and 100 cm.
C3L=shallow soil, less than 30 cm; stone content rich; texture of
topsoil loamy; blockage on gravel.
Ill
C H A P T E R VIII
SOILS OF THE BALIKH BASIN
A review of methods of soil analyses is kept as brief as possible while
problems met with texture analyses are discussed in more detail.
Field description and analyses of the soil profile are given.
Classification of the soils according to the "Soil classification , a comphrehensive system, 7th approximation" (1960) with supplements (1964, 1967) will
be dealt with.
The micromorphology of the soil profile together with soil analyses are
used as a basis for the evaluation of soil genesis. This subject is treated separately in chapter EX.
A. D e s c r i p t i o n and a n a l y s e s of t h e s o i l
profile.
1. DESCRIPTION OF METHOD OF ANALYSES
Methods of soil analysis are described in detail by Jackson (1956).
The analyses were carried out in the laboratory of the Royal Tropical Institute at Amsterdam and in the laboratories of the Soils Department and Analytical Chemistry of the University of Utrecht.
In addition to normal chemical analyses the following determinations were
made in order to estimate soil salinity:
—the electrical conductivity of the saturation extract (EC e );
—the electrical conductivity of the soil: water/l:5 extract (EC.) and determination of the different anions and cations in this extract;
—the content of gypsum (% CaSO.).
112
The EC. was determined only if the EC,- was more than 0,5 mmhos. The
EC of gypsum soils was much lower than could be expected from the ECg-values, gypsum being less soluble in the saturation extract. Gypsum was determined only in samples with a content of sulphate and calcium ions in the 1:5
water extract of more than 1 me/100 gr soil.
Texture was determined without pretreatments to destroy organic matter,
free iron oxides and carbonates. Thus determined texture figures give an approach
to field-textures (as it is in situ).
Some additional data and problems met with texture analyses are discussed
in section 2.
Methods of mineralogical analysis of the clay fraction are discussed in
section m , B , l .
Total analyses of the clay fraction < 2 ß and fine earth smaller than 2mm
were performed with Philips X-ray Fluorescence Apparatus (PW 1540, PW 1051,
PW 1010); of selected samples also the silt fractions 5-10 |A and 20-30 p, were
studied.
The samples were fused with lithiumborate (soil: lithiumborate=l:5) into
a glass. At the end of the fusion the melt was poured into an aluminium ring placed on a polished plate of graphite at 450°C. A copper weight was placed on the
melt in order to from a glass button. A well-sized glass button weights 4,5-5
grams. The applied dilution with lithiumborate should not be more than ten times.
For further details on X-ray fluorescence one is referred to Reynders
(1964).
Micromorphology:
Mammoth-sized thin sections of soil (15 x 8 cm large and 15 p, thick) have
been prepared by the Laboratory of Micromorphology (The Dutch Soil Survey
Institute, Wageningen, The Netherlands). This has been made with unsaturated
polyester resin Vestopal-H.
For further details one is referred to Jongerius.and Heintzberger (1962).
2. TEXTURE ANALYSES
Texture of soils was determined with different methods:
A. Standard method with dispersion agents sodiumpyrophosphate Na.P„O . 10
H-O and sodium carbonate Na0CO„ without pretreatments to dissolve free
113
carbonates and without destroying organic matter.
B. International method with pretreatments of 30% hydrogen Superoxide and 2N
hydrochloric acid and in addition sodiumacetate buffer pH 5 added before.
Results of method A are given in fig. 20 and section 3 in percentages of
oven-dry soil, containing free carbonates and those of method B in table 28 in
percentages of the mineral soil without free carbonates.
The percentages of clay and silt are often underestimated in method A.
This may be due to the occurrence of pseudo-silt and pseudo-sand. These particles are not completely dispersed by the dispersion agents of methods A, but
disperse after pretreatments with sodiumacetate and hydrochloric acid.
Large differences in texture with different methods have been found in
aeolic loams and soils of the Balikh region. The difference is smaller in soils
of the Volcano region.
The C. E. C. of topsoils from brown loams on the terraces is equal to or
higher than that of the subsoil and much too high for the low clay and humus
content.
Therefore, the fine silt fraction can be expected to have a large content
of clay minerals which is confirmed by minéralogie analyses (table 21).
Apparently there is a cementation of clay minerals caused by carbonates,
and by silica and alumina in the zone of weathering that is the topsoil (see Reynders 1966).
Palygorskite of topsoil samples has been found by electron microscopy to
be cemented into clusters (analyses carried out by Wiersma 1966.)
Texture of gypsum soil was determined only by sieving methods. The results
are shown in table 29 .
The fraction smaller than 50 IJ. can not be subdivided in other fractions due
to the influence of Ca
114
ions which prevent the dispersion of clay.
100%
50-2000 M.
Fig. 20. Ternary diagram with texture data of brown loam deposited on the Pleistocene terraces.
Texture of soil was determined with the standard method A.
Table 28. Texture data after pretreatments with sodiumacetate buffer pH 5, 30% hydrogen Superoxide
and 0,2 N hydrochloric acid; dispersion agent sodium pyrophosphate, (method B.;
sample Region
number
15 I Balikh
15 II
15 III
15 IV
sample Region
number
16 I Volcano
16 II
16 III
16 IV
30 I Gypsum
30 II
30 III
depth
in cm
2-0,5
mm
0,5-0,21
mm
0,21-0,05
mm
0-12
15-25
40-50
90-100
0,08
0,2
0,3
0,2
0,1
0,1
0,1
0,1
depth
in cm
2-0,5
mm
0-4
40,8
20-30 40,5
60-70 54,0
145-155 70,7
0-5
8-13
20-30
1.1
1.3
1.9
5-2
20-10
M-
10-5
u.
IJ-
V- < 2 (j.
0,4
0,6
0,5
0,5
4,2
2,8
2,8
4,7
9,9
7,8
5,7
5,8
4,9
3,7
3,9
5,6
6, 3
6, 1
5, 5
7, 8
0,5-0.21
mm
0,21-0,05
mm
50-20
U
20-2
10,2
12,4
11,8
18,4
14,3
16,0
6,9
5,4
9,3
1.6
4,2
3,8
3,3
12,0
18,5
15,1
18,1
24,1
23,6
9,4
7,0
50-20
U
<2n
8.8
10,3
10,7
10,0
13,3
12,7
2.4
4,0
29,5
22,3
23.5
35,1
30,1
32,7
74,0
78,8
81,2
75,2
note: The results with method A of profiles 15, 16 and 30 are given in table 30.3, 30.10, 30.8 respectively.
115
P.'j
6i' 1
Table 29. Texture of gypsum soil as determined by sieving
methods.
Sample
depth
number
cm
>50'Op.
50-500 IJ,
< 50 M.
30 IV
30 V
30 VI
35-45
55-65
80-90
5, 5
6. 7
36. 0
50,0
61,0
28,7
44,5
32,3
35,3
in
3. DESCRIPTION AND ANALYSES OF THE SOIL PROFILE
Chemical and analytical data together with the profile descriptions are
given in table 30.
Methods of analysis are described in section A, 1 of this chapter and section B, 1 of chapter in. For notations of clay and silt fraction minerals one is
referred to section B, 1 and C (table 21). of chapter HI, and for mapping methods
and field classification symbol to chapter Vu.
a. S o i l h o r i z o n
designations.
The ABC soil horizon designation enables one to rapidly recognize genesis
with the aid of a symbol.
Generally the properties of arid soils are dominated by authigenic carbonate
which overshadows the non-carbonate material.
The original designation C
is unsatisfactory because it fails to indicate
the dominant soil properties.
Gile, Peterson and Grossman (1965) proposed the introduction of aK-horizon, defined as follows: an horizon showing a prominent accumulation of finegrained authigenic carbonates, which coats or engulfs skeletal pebbles, sand
and silt grains as an essential continuous medium (K-fabric).
Since the profiles examined by these autors all had a high content of fine
sand, the calcitans of the skeleton grains easily could be connected owing to the
small distance between these grains.
A continuous calcareous fabric was not found in the Aridisols of the Balikh
Basin, these soils requiring a very high percentage of carbonates for developing
a continuous K-fabric due to their high content of clay and fine silt.
However, the calcic horizon found in the soils has a lot of properties in
common with the K-horizon. Therefore, horizons showing a prominent accumu116
lation of fine-grained authigenic carbonates and a high content of clay and fine
silt are indicated with the symbol (K).
Thé following soil horizon designations are used:
(A ) an ochric epipedon with a crumbly structure.
(A..) an ochric epipedon with a platy structure.
(A ) an ochric epipedon with ploughing practices.
(B)
a cambic horizon having textures of loamy very fine sand or finer in the
fine earth fraction, a crumbly to subangular blocky or blocky structure
and showing evidence of removal of carbonates.
(K..)
a transition to the calcic horizon having lime accumulations (less than
5 percent by volume), 35 percent or more by volume of fine-grained authigenic
carbonates in the soil plasma and a slightly hard blocky structure.
(K ) a calcic horizon having many lime accumulations (more than 5 percent
by volume), 50 percent, or more by volume of fine-grained authigenic
carbonates in the soil plasma and a hard blocky structure.
(K ) immediately underlying the calcic horizon and having lime accumulations
3
(less than 5 percent by volume), 35percentormorebyvolumeoffinegrained authigenic carbonates in the soil plasma and ahard blocky stucture.
C
soil parent material which is unconsolidated and does not show properties diagnostic of the other master horizons.
C
C-material with a gypsic horizon; structureless,
cs
C
C-material with some lime mycelia.
J
ca
C .. C-material with vertic properties e.g. cracks and slickensides.
He
indicates material being different from the C-material.
117
TABLE 30i PROPILE DESCRIPTION CHEMICAL AND ANALYTICAL DATA OP SOILS OF THE BALIKH BASIH.
TABLE 3 0 . 1 : TYPIC TORRIFLtJVENTS.
Sample
Textura U.S.A.
depth
aand
ailt
clay
Sample
number
gravai 2BD-5OH 50-2 u 2 M
C/B
*
CaCO.
0,74 0,09 8,2
20,1"
12,4
-
21,3
14,3
20-1
0-5
20-11
30-35
6O-65
20-111
20-IV
521
85-90
20-30
52II
5O-6O
17,0
60,9
22,1
6,3
68,1
25,6
30,6
59,7
9,5
1.9
27,0
72,9
25,2
34,9
55,7
54,3
iSxchangeabla baaaa na/iOO K
8,6
8,8
8,4
8,2
8,4
18,7
8,4
-
-
-
20,1
-
23,1
0,42
'4,5
19,1
1,15
3,90
22,1
1,49
2,64
13,1
13,1
1,45
24,4
2,09
3,16
14,6
14,6
2,74
26,0
13,6
13,6
4,41
14,4
Exchangeable baeea me/100 K
Ca Mg
C.E.C.
.e/100 g
5,43 0.,27 0,51
6,90 6,72 0 ,62 0,40
5,82 6,86 0:,32 0,60
0,42
19,1
22,1
24,4
8,61 3,43 0;,84 0,19
18,2
0,03
0,53 0,08 6,6 14,7
-
5,38 I ,05 0,22
6,53 0 ,96 0,33
C.iäTi
>e/iOO |
Sun
*
gypaum
ie/100 i
10
Ca
«g
K
Ha
HCO,
CI
0,59
0,75 1,63 0,04
tr
0,52
0,78 1,10 0,03
tr
0,47
0,26 0,49
0,47
0,69 2,00 0,01
Sum
1,42 0,89 0,21 1,06 3,58
3,01
0,50
0,87 0,57 0,13 0,75 2,32
2,43
0,27
0,40 0,21 0,14 0,44 1,19
1,22
0,64
1,16 0,57 0,03 1,25 3,01
3,17
tr
3,84
2,70
8,34 7,58 0,22 6,33 22,5 22,2
tr
0,31 12,2
7,49 5,29 0,08 4,59 17,5 17,0
tr
0,28
0,64
t7
S0J HO,
9,60 0,12
4,78 11,9 0,02
of the clay fraction
Chemical and minéralogie*! i
tr
(< 2 n )i
Sample
Clay Minerals
•umber
20 I
20 I I
56 , 7
56 , 2
15 ,6
t5 ,9
20 i n
56 , 0
54 , 8
15 , 9
16 ,o
20 IV
9, 4
4,6
1,1
3,9
9, 6
8, 5
3,1
3,6
0,9
1,6
1,5
8, 9
3,7
0,9
2,4
3,6
2 , 3 93,6
2 , 1 89,4
2 , 2 90,1
6, 2
6, 0
16,3
15,6
2 ,6
2 ,6
Ho
Ko"
Chi
Chi*
6, 0
17,6
2 ,9
«o**
2,0
5, 9
16,6
2 ,8
Mo**
89,9
Chi*
P I
P I*
P I*
If
K*
K
Chi*
P I*
K
a
a
a
a
Chemical a n a l y s e s of t o t a l s o i l sample (< 2 i
Sample
Al_0,
Fe.i
MgO
CaO
.otal
»a-O K-0
^°2
number
20 I
43,8
6,5
6,3
5.0
9.1
6,3
1,6
0,2
78, 8
11 ,6
18, 7
1 ,6
20 I I
41,8
7,6
6,3
5,0
10,2
4,0
1,6
0,2
76, 7
9,4
1 ,9
20 I I I
40,7
6,8
6,0
4,7
11,8
3,6
1,5
0,2
10 ,3
20 IV
38,2
6,7
6,6
5,4
12,6
5,1
1.4
0,2
75, 3
76, 2
17, 8
18, 3
9,8
15, 9
1 ,6
1 ,8
TABLE 3 0 . 2 : TYPIC USTIFLUVENTS.
•ample
Sample
•umber
7 I
EC
4
texture U.S.A.
£*h
cm
clay
gravel
2am-5O
5O-2 M
0-10
2,6
83,1
14,3
30-40
2,3
57,2
40,5
1 I
a
-5
Ca
5 water extract
atio n s
K
»g
Ha
Oe/i00
g
Sum
Sum
0,19
0,86 0,11 U,15 0,15 1,27 1,19
0,17
0,80.0,12 0,09 0,13 1,14 1,06
118
»
<. 2 u
CO3
0,93
HC 0 .
o, 78
o. 65
C/H
0,15 6,2
Cl
tr
tr
M
27,5
26,2
4
B0
o, 39
0 ,02
0 ,01
0,
40
3
26,5 4,06 2,45 0,18
T37T-
33,2
26,2 5,55 1,94 0,18
33,9
33,9
034~
0,53
Profilât 20.
Hst« of obB«rratiom April 1966.
Loc»tioni Eupfcratea valley, fiaq.q.a Saura Uaetije.
Elevation! 240 a.
Baliafi
flat on 5» distance of a shallow dry rivar channel.
Land usai cotton.
Parent material! Holocana Euphrates lowest terrace.
Soil conditional s l i g h t l y aoiat to s l i g h t l y wot.
Soil Burfaoet ploughed.
Field c l a s s i f i c a t i o n ! AOLr.
Soil typei Typic Torrifluvent.
( A )
0-13 ca
Slightly moist, light olive brown ( 2-5 Y 5/4) a i l t loam, rooted,containing very l i t t l e
organic material, soft sedimentary
mi crop la ty fabr ic • soft weakly de v© loped crumbly to subanûlap bl ocky a true tur$ with many biopores * merging ^3*sdually into 1
C.
13-45 cm
C
4^-30 cm
C
6O-97 cm
s l i g h t l y moist, oliv» brown { 2.5 Y 4/4) e i l t loan, rooted,
soft weakly developed crumbly to aubangular blocky structure v i t h
many biopores, sedimentary platy fabric and occurrence of clay loam bandst merging gradually intoi
olightly aoiat to s l i g h t l y wat, olive brown ( 2.5 Y 4/4) a i l t loan, poorly rooted, very weakly nottled, very aoft consistence,
micropores, sedimentary platy fabric,
occurrence of clay loan bands) merging rather quickly intot
s l i g h t l y wet, olive brown to very dark greyish brown ( 2.5 Y 3/3) e i l t loan, poorly rooted, weakly mottled, soft
consistence,
few biopores, sedimentary platy fabric and occurrence of some sandy bands.
Profile 1 52
Dat« of observation! April 1966.
Location! south-east of Bamret Jamati.
Elevation1 237 a.
Seliefi
flat.
Land use! fallow.
Parent material! Euphrates alluvium.
Soil conditional aoist.
Field c l a s s i f i c a t i o n )
AOUa^
Soil typ«1 Typic Torrifluvent
(A. )
0-10 cm Moiet, light oliv« brown (2.5.T 5/4) a i l t loan, containing l i t t l «
organic material, weakly developed soft crumbly structura)
merging gradually intoi
Cj^
1 0 - 7 5 cm a o i a t , o l i v e
C2
75-100cm n o i a t ,
Profilai
brown ( 2 . 5 Y 4 / 4 ) s i l t
loam w i t h s a l t « c c u n u l a t i o n s ,
o l i v e brown ( 2 . 5 Y 4 / 4 ) sandy a i l t
sedimentary p l a t y f a b r i c ! merging g r a d u a l l y
loam w i t h s a l t a c c u m u l â t i o n s and m i c r o - p l a t y
iatoi
fabric.
7-
Date of observationi March 1966.
Location! aouth-west of Bavïje.
Elevation! 29Ö m.
Belief! valley bottom.
Vegetation! grasa.
Parent material! Wadi al Cbeder alluvium, flood plain.
Soil conditions! moist.
Field c l a s s i f i c a t i o n ! AOL/Clr
Soil typei Typic Uatifluvent.
(A^)
0-20 en
Hoiat, strong brown (?.5- YB 4/6) s i l t loam, containing l i t t l » organic material, weakly developed aoft crumbly structurel
merging intoi
c
1
20-50 cm
moiet, strong brown (7.5 YB 4/6) s i l t y clay, Bottled,
C2
50-IOOcm
moist,
dark brown ( 7 . 5 YB 4 / 4 ) d a y , B o t t l e d ,
fine platy fabric, small limeatone blocks) merging into!
fin» platy
fabric.
119
TABLE 3 0 . 5 1 VERTIC USTIFLUVENTS.
Sauplo
nuabar
15-1
15-11
15-III
15-IV
grav«:
ca
0-12
I5-25
40-50
90-100
pH
T.Tt ur. U.S .A.
silt
sand
clajr
2aa-5O u 5O-2 u * 2 U
dapth
0
0
0
6,9
4,8
41.2
3,4
1,7
30,9
35,2
0
38.0
C
li
8, 1
51,9
57,2
65,7
63,1
B
CaCO
C/B
0 10,0
1 ,04 0,
8,2
8 ,3
8 ,5
1 5 "»ter extract ae/100 g
cations
Ca
Sua
Ha
Sua
"g
n
5.59 2,16 0,10 2.67 10,5 10,5
oattar
Orn»nio
-
-
-
-
-
-
-
-
-
C«
S JpIlUB
27,6
29,3
32,4
33,1
t
MS
.
tr
tr
-
ë fitl*
2 ,53
Ha
Sua
39, 1
25 2 9 .97 2 ,00 0 .78 38, 0
0 ,89 0 . 4 1
22 2 8 .04
31, 5
1 .65 0 .39
21 5 1 1 . 9
35, 4
26
tr
1.32
n./lOO g
39,1
38,0
31,5
35,4
B.5.P.
3 .38
2 .05
1 ,30
1,10
1
ffi
x 103
5.15
3.22
-
5 ,
x ÏO3
1,50
0,72
0,34
0,25
0,92
0,53
0,46 0,01
0,35 0,02
0,41
0,44
an i ono
CO
HCO.
Cl
tr
0 ,36
0 ,87
9,19
0,08
1,80 1,91
tr
0 ,46
0 ,46
0,89
0,10
1 • 34 1,37
tr
0
,55 0 .21 0,57
0,04
Cbaaica 1 and ninaralogical analysas of the clay frac
ion
(
2 u) .
Al
P.2O,
S0„
"°i
1
nuabar
*2°,
15 III
15 I '
8, 4
8 6
48,6 15 ,1
51,4 16 ,0
4,7 0,
5 2.3
5,5 0,
5 0,7
SiO2
5,5
5.5
2,1 81,1
2,3 85,C
Cbsaica 1 and ain• rai cgi cal analysas of ths silt frac
ion
8,2
8,7
3,8
3,6
2,8
15,6
16,2
Mo Chl
No Chl
2,9
p* 1**
p* 1**
* Q
p
* y
** y
p
«
?
5-10
SiOj
P«2°3 "SO
—
nuabar
9,3
15 «
15 III
54,3
54,4
50,4
13,9
•4,2
15,6
8,2
3,9 3,7
9,5
15 I»
55,7
15.0
9.5
3,8 2,2
5,9
15 I
5" y
y
IS !
2,1
2,8
17,8
94, 4
2,9
M0
2,7
94,2
5,5
16,5
3,0
95,2
6,4
15.6
2,5
cm
Mo Chl
P
1
K
p i
P
I
<i
p
<i
p
K y P
ap
Saapl«
nuabar
15
15
15
15
I
II
III
I»
Saapl«
nUBbar
1S-I
19-11
19-111
19-lï
19-»
27-1
27-11
27-111
27-IV
51 I
51 11
51 I I I
43,1
41,5
38,3
37,8
6,8
',5
6,2
7,0
aaapla
d«ptb
5.7
5,8
5,7
5,7
*
gravel
4.2
4.3
4.7
4.8
14,5
15.5
16,5
16,7
TTtur« U.S.A.
•and
silt
2aa-5O u 5O-2U
2-7
20-25
n.a.
1,6
n.a.
32,1
6C-65
90-95
140-150
1,1
1,2
12,2
39,8
51,0
1,0
0-5
5,6
15-23
40-50
70-80
5,2
0-10
30-40
70-80
2,2
55,1
49,2
41,2
5,1
4,0
41,9
66,9
28,5
17,7
1,7
1,4
1.7
1.7
1.7
1.7
3,4
2,8
5,8
2,3
0,1
0,1
0,1
0,1
79,5
78,2
79,0
76,1
10,9
11,0
10,6
9,3
20,5
19,2
16,2
18,0
1,9
1,8
1,7
1,9
ng+abl* b t n i a«/iOO g
Organic Mtt«r
clay
TT
< 2 u
n.B.
66,3
86,7
59,0
48,0
»,J
8,5
8,4
8,4
8,0
1,31 0,14 9,4
39,3
45,6
8,0
8,0
0,59
53,7
54,1
8,3
8,4
7,7
7,8
30,9
69,8
60,9
0,76
21,5
20,9
22,0
0,09 6,6
0,11 6,9
8,1
t
r
tr
22,3
21,2
0 ,02
29,6
30,3
30,6
30,0
tr
25,5
27,3
1.13
0 • 34
25,9
0 ,03
tr
-
"ÖT3S"
3,14
-
2,22
2,04
-
4,52
4,58
4,50
0,36
0,49
0,70
0,41
0,49
0,43
0,31
0,34
2,92
1,56
0,92
120
na
n.n.
0,62
TUB
na
no
0,77
0,98
1,00
i|25
0,53
0,05
0,06
1,31
1,21
0,58
0,69
0,48
0,55
0,46
14,1
6,33
1,78
0,56
6,1
2,67
1,25
0,14
0,06
0,04
0,02
0,01
0,16
0,09
0,06
na
na
na
0,93
1,27
0,31
2,57
3,56
1.98
2,62
0,66
3,43
0,60
0,62
0,57
0,40
2.54
2,34
2,50
2,33
1,57
1,73
22,2
0,52
0,63
0,65
10,9
4,10
0,45
0,54
0,54
0,81
1,59
1,84
1,83 22,2
1,80 10,9
1,11
4,14
1,97
0,50
0,40
ru»
na
o,73
0,25
0,96
1.71
1,87
0,82
0,
08
0,43
0,34
1,20
0,
37
1,14
o. 33
0,25
0,25
0.58
0,70
1,30
0,57
0,69
21,1
0 , 12
0,25
1,00
9,75
2,26
24,5
26,3
9, 26
11 ,4
21,5
20,8
28,1
14 , 1
9, 44
19,6
18,6
7, 35
9, 59
15,7
12,8
11 ,4
20,4
20,5
16,5
et rue t m/iOO g
2,12
C.E.C.
B*/1OO g
C/N
nu1
na1
tï
ti
0 , 14
0,
07
0,
03
;r
16 , 1
15 , 0
12 ,6
11 ,6
14 ,9
2.25
1.79
1,64
0,58
1,08
36,6
40,6
36,6
40,6
1,59
2,66
1,25
1,08
38,5
39.5
40,7
38,5
3,25
2.73
1,16
1,47
2,73
0,47
1,73
0,36
1,35
1,16
1,02
0,34
0,46
0,71
2,63 0,93
2,13 1,56
1,91 0,93
29,2
29,9
.28,9
39.5
40,7
29,2
29,5
36,6
29,9
28,9
29,5
36,6
35,8
34,2
35,8
34.2
1,23
1,14
1,59
2,41
2,54
4,36
2,72
Profil«! 15.
Location 1 north of Etsiaah.
Dat« of observation 1 Àuguat 1965.
Elevation • 270 a.
Relief
• flat.
Land uae 1 ootton.
Soil conditiona 1 >oi«t to wet| Irrigated 15 *»*• *«°Pield classification
1 AOClhrv.
Soil type • Y«rtlc Ustifluvent.
( A., )
0-12
C
12-26
OB Motet,dark brown ( 13 TB 3/3) « i l t y clay, containing organio «atter, poorly rooted, the upper 3 ca have a platy structure,
3-12 ce aoft crusbly atruotur«, cracks on surface 1 aerging Irregular intoi
en
Vet, dark yellowish brown ( 10 TB 4/4) clay with black organic «pota { 10 TB 2/i
), «oft fine platy «ediaentary fabric,
poorly rootedi aargiog gradually intoi
C
12 vertic
wet, dark yellowiah brown { 10 IB 4/4) olay, accumulation of clay and black organio material in cracks, aottled, «oft
26-100 CB
C 13
_ , _ . . . __„.
100-200 ca
Profil«
,.h,,._
lnn.lW
-liek.n.idee. . „ „ i n .
fin«
intoi
wet, brom ( 7-5 ™ SA) olay with BOttl««, «oft fine platy aediaentary
fabric.
• 19.
Sate of observation • March 1966.
Location 1 north of Baqqa Saura.
El«Tation • 241,5 a.
Relief
l.flat.
Native vegetation 1 buahe«.
Land use 1 liquorice plant.
Soil condition« • aoist to alightly wet.
Soil surface
• weakly developed g i l g a i
Pleld classification
relief.
1 AOClrbv.
Soil type 1 Tertic Uatiflurent-
(1 )
0
-
tl ca
11
-
86 ca
Moist, dark brom (7-5 TB 4/4) clay loam, containing vary l i t t l e organic Material, poorly rootad, weakly Bottled,
aany crack«, 0-0,2 ca platy fabric, tendency to orunbly structure, nonp.la«tlc| »erging gradually intoi
C
vartio
«lightly wat, dark yellowiah brown (iO TB 3/4) olay, aany old root fragnanta, poorly rooted, crack« ar« partly
inhubittid
up to 86 ca by root« with a maximum diameter of 3 ca, Bany mottle« between 11-24 cm amd 64-66 ca,
aaall clay-bunua accumulation», «oft plastic sedimentary micro-platy fabric, aany »licken»id»s I Barging
gradually intoi
C -
86
- 105 ca
aoiat, dark brown (7-5 TB 4/4) clay, vary auch aottled, soft plastic s«diB«ntary micro-plat y f a b r i c
Profil«1 27.
Sate of observation! May 1966.
Location! east of Eaiimah.
Elevation 1 265 a.
Reliefi
flat.
Land usai cotton.
Parant material 1 Balikh alluviua.
Soil conditional «lightly Boi«t.
Soil surface! ploughed.
Pield olas«ificationt
a0-I Clhrv.
Soil typei Vertic Uetifluvent.
(a )
0-10 ca
Slightly mo i e t , dark yellowiah brom ( 10 TR 4/4) a i l t y clay loan, containing l i t t l e organic material, poorly rooted,
medium hard fine to nediu» blocky «tructur«, «ticky when wet; aerging gradually intoi
C
11
10-35 ca
moiat. dark yelloviah brown (10 TB 4/4) a i l t y clay, containing l i t t l e
fine gravel, intensively strong brom aottled
( 7.5 TR 5/6}, having vertical tongue» of dark yellowish brown clay, poorly rooted, aoft to medium hard «ubangular
blocky to blocky »tructure,
C
12 vertio
35-70 cm
internal aicroplaty fabric, sticky when wet, Barging gradually intoi
»lightly ooiot, dark yellowish brom (10 TB 4/4) s i l t y clay with atrong brown (7-5 TB 5/6) mottle», having nose dark
yellowish brown tongue», very poorly rooted, very hard angular blocky »truetore to l o c a l l y «harp wedged struotur«
(parallelopipada), with »lieken»idea on the«« «harp «edged elenentsf merging gradually intoi
C
13 vertio
70-160 ca «lightly mo i e t to dry, dark brom (7-5 TB 4/4) « i l t y clar with brom (7-5 TB 5/4) a o t t l « s , with BOB« dark y«llowiah
brom tongute up to 1 a, very poorly rooted up to 1 B, b>rd angular blocky atruotur«, l o c a l l y »lickenaidee on p a r a l l e l epiped structural aggregate».
Profilai 51
Dat« of observation! March 1966.
Location! north-west of Bhayat.
Elevation 1 260,5 a.
Heli.fi
flat.
Land usai cottonParent material 1 Balikh alluvium.
Soil condition»! a o i s t .
Pield c l a s s i f i c a t i o n 1 AOL/Clr(bvc)
Soil typet Tertio Datifluvant
(*,)
O-30 ca
Moist, dark brown a i l t y clay loan, containing l i t t l e organio aaterial, weakly developed «oft orunbly structure, strongly
nottied( aerging gradually intoi
C
H
C
12
30-40 ca
Tertio
a o i a t , dark yellowish brown c l a y ,
fine platy fabric, Bottled,
40-100 CB moist, dark yellowish brown s i l t y c l a y ,
faw 11B« accumulation»! Barging gradually intoi
fine platy fabric, few l i a « and g7p»uo accumulation», »lickeneide«.
121
T A B L E
3 0. 4 ;
T Y P I C
n u a b a r
sample
d e p t h
in
cm
5-1
5-n
5-111
5-IV
15-25
40-50
75-85
Saiapl«
C A L C I O R T H I D S i L O A M Ï
Texture
t
sand
gravel
2 n m - 5 O u
0-8
œ
E. S. P.
silt
c l a y
50-2
n
24-1
24-H
œ
C
I
7 2 , 3
17,2
8,7
63,4
61,9
50,0
28,1
31,0
29,5
8,9
8,9
9,1
1,19
matter
0, 14
0,57 0 , 0 .
0,14
0,13
0,16
0,45 0,08 0,12 0,08
0,45 0,04 0,01 -0,20
0,42 0,02 0,01 0,38
0,12
83, 8
81, 4
5,4
5,7
0 ,6
0,0
0 ,5
0 ,7
0,4
0 ,5
81,
1
0 ,9
1 ,1
0 ,6
4
6,2
6,8
0,7
81,
0,3
0 ,6
dflptb
**
0-8
8-15
2BO-50 v
Sum
Sua
CO,
0,07
0,00
1,46
tr
1,5
1,5
3,5
70-80
0,13
0,44
0,21
0,79
0,10
—
0,43
1,11
5,63
0,65
1,01
0,24
0,28
0,73
0,70
0,83
Cl
tr
0,62
0,62
0,67
I
4,6
3,4
3,6
3,3
4,7
0 ,9
2 ,5
91 ,0
4,2
16,2
84 ,5
84 ,1
4,0
15,8
4,1
18,8
81 ,4
4,2
13,6
3,9
5,0
4, 3
3,5
Ho
3,9
3• 9
4,6
3,2
28 ,0
13 ,"0
95,8
24 ,1
13 ,8
2, 1
95,9
22 ,5
10,2
2, 1
95,8
20 ,4
11 ,2
Ko H
Ko H
Ko X
Ko H
0,09
0,30
0,09
CaCO.
Sum
C
°3
ons
BC03
Cl
SO.
0,25
0,20
0 ,0
0,89
0,0 7
0 ,65
0 ,45 1 ,43
0,3 3
0 ,73
0,19
1,12
0 ,97
tr
0 ,01
0,89
2,25
2 ,01
tr
0 ,01
2,03
3,33
2 ,94
tr
16,8
8 ,1
5,4
0,8
3,4
2 ,3
15,6
7,6
7.1
0,7
2,9
1 ,9
2
O
F.2O
89,8
5,4
91,0
6,1
„ ,7
i
24
m
24 IV
37,7
37.7
10,0
8,7
122
5,1
3,5
4,2
4,2
4,3
y
C.K.C. •
Ca
Mg
16,7
17,3
17,2
14,6
T ^
2,88
3,91
3,99
os/100 g
20,5
21,4
21,8
20,5
K
Ï767
1,02
0,43
0,16
19,6
9,8
10, 4
12, 7
z,6
2,
9
4, 2
4, 5
,4
1,4
0,2
0,2
0 0 , 3
1,5
0,2
71,7
1,2
0,1
74,3
80,9
tj,
5
8,3
6,4
7, 4
P' l'* K 4 7
r*
P* 1 ++ K* 4 F
Ho
C h l
3,3
3,2
Ho
Chl
Ho
C b l p"
CaO
0, y
m i 10 rals
C l a y
3_
3,2
• (< 2mm)
5,4
5,5
3,5
P
B0 3
A 1
I
5,2
4,9
90,8
55,2
0,6
SiO
16 ,7
2 ,6
III 53,0
9,7
9,7
7
g
SUD
5,1
4 7 , 2
I"
7
7
Erohang«abl*> ban nu m«/.00 g
gypsi
6,7
3,3
8,6
8,7
a
48,6
4
4
4
4
l"
:4 T
Organic mattsr
0,60
I
l"
sio 2
9 6 , 0
17,2
24 1
24 11
33,1
30,7 30,7
30,4 30,4
29,4 29,4
a l n s r a l s
Chi
Chi
P
P
P
Ko Chi
Ko Chi P
Ko
1,8
2, 1
,52
0 ,51
0 ,40
nuab«r
lt.1
g
»o3
C l a y
5.0
,56
MgO
0,09
m e / 1 0 0
S I O ,
58,07,9
56,2
19,9
47,5
32,1
47,0
32,2
anal
2.94
3,36 2,71 0,07
4,12 1,20 0,10
1,42 0,43 0,18
C.E.C.
g
Sum
0,02
0,02
0,03
B a 2 O
,01
0 ,04
Sampl«
Ha
0,77 0 , 0 3
24
24
2,68
m e / 1 0 0
K
clay fraction (< 2u)i
52,0
24 I»
b a s e s
g
2 7 , 4
24,6
25,0
27,4
*>„
0,60
0,60
0,64
Ch ffllcaland B i n e r a i Oglca 1 analyses of the clay fraoti n (*.2 V. ,
Sample
SiO,
Total
?•
number SiO,
"2°3
2°3 'eo CaO H a 20 K
24
-
0,66
C/H
1 t 5 vat«r «tract M / 1 0 0
cation»
K
Ha
Ca
Kg
17,7
aniono
H C O .
50-2n
34,1
23,9
20,4
20,8
gypOUD
K
g
T s i t u r s U.S.A.
clay
ailt
aand
CaCO.
21,7
25,8
24,9
Va
K
C/J
0, 14
o a t i on.
Ca
Exchangeable
Ca
%
and ninaralogical analyeos of tha oilt fraction 20-30 111
sio 2
Al O F* 0-. MfiO CaO Ma 0
e
-
*
8,5
7,1
20,5
z 10J
24-111 25-35
24-IT
*
10,5
Chsaioal and mineralogies! analysas of the
Sanpls
S i O ,
« 1 . 0W
K g O
C a O
2 3
numbsr
5 I
49,9
20,3
8,3 1 ,6 1 , 3
5 II
46,6
19,7
7, 9 » ,8 0,4
7, 1 1 ,8 0,4
5 III
49,5
20,8
5 IV
46,4
18,9
9,2 0 ,6 0,5
Saapls
numb.r
Organic
V
1,5
1,5
1,5
EC
0,23
0,33
0,61
R E C I O H .
pH
<. 2 V
a « / 1 0 0
e
—
ChiBical
Sampl«
nunbtr
5I
5 II
5 III
5 IT
T E R E A C E
0
*> ,
0,27
H Z
O F
U.S.A.
24 ,5
23,1
2,9
29 ,9
20,3
4,7
2,7
2,8
+
1
K
Q
P
Ha
Sua
0,13
0,16
0,27
1,74
21,4
21,6
20,5
E.S.P
0,64
0,75
1,24
8,50
Profil« i 5.
Date of observationi June 1965.
Location* Hanret terrace, east of Sbininah.
Blsvationi 259,3 »Eeliefi flat to faintly «loping.
Lind us« »ad native vegetation) oereals and thistles.
Parant materiali loamy o over on Middle Pleistocsna terrace.
Soil conditional dry.
Fiald classification! JLoLb.
(A )
(B)
(K2)
(Kj)
C
O - 8 on
Dry, light yellowish brown (lO TB 6/4) s i l t loan, containing l i t t l e organic material, well rooted, 0-2 cm platy structure,
2-8 en soft to slightly hard crumbly structure! merging gradually intoi
8 -26 cm dry, reddish yellow (7.5 TR 6/6) s i l t y clay loam, wall rooted, soft to slightly hard crumbly to subangular blocky structure;
marging gradually intoi
26 -67 cm dry, strong brown (7-5 TH 5/8) silty clay loam, containing few l a p i l l i , poorly rooted until 50co, slightly hard
6
7 -100 en
subangular blocky to blocky structure, many hard white lime concretions) marging gradually intoi
moiat, strong brown (7.5 TR 5/6) clay loam, containing l a p i l l i , hard blocky structure, small dark brown clay humus
accumulâtiona, soft small lime accumulationst marging gradually intoi
100 -220 cm dry to slightly moist, strong brown (7.5 TH 5/6) loam with intercalations of thin l a p i l l i layer«, soft structureless,
locally small spots with lime-nycelia) lying over gravel.
Profile 1 24.
Date of observation! June 196S
Location t Haqqa terrace.
Elevation 1 268 n.
Relief t flat to faintly aloping.
Land use 1 cereals.
Parent material 1 loamy cover on Upper Pleistocene terrace.
Soil condition»! dry.
Soil surfaoe 1 ploughed.
Field classification 1 ÀOLb.
Soil type 1 Typic Caloiorthid.
(A )
0
-
(B)
8
-
(K^)
15 -
(K2)
43 -
<K,)
C
100 140 -
8 CD Dry, yellow (1O TH 7/6) * i l t loan with some fine gravel, containing l i t t l e organio material, poorly rooted, soft crumbly
etruoture) aerging gradually intoi
15 em dry, yellow (lO TH 7/6) s i l t loam, containing very l i t t l e organio material, very poorly rooted, slightly hard crumbly
structure, few soft white lima accumulations merging gradually intoi
43 cm dry, reddish yellow (7.5 TR 6/6) s i l t y olay loan, Yery poorly rooted up to 40 cm, hard granular to subangular block?
struoturs, «ome clay-humus accumulation», many slightly hard liaeconcretiona; marging gradually intoi
100 cm dry, etrong brown (7.5 TB 5/8) s i l t y olay loan, very hard subangular blocky to angular blocky atruotur», aome olay-humua
accumulations, bard white lime concretion» abundant) merging gradually intoi
140 on dry, reddish yellow (7.5 TB 6/8) s i l t loam, mottle«, lime accumulations) merging intoi
150 cm dry, reddiah yellow (7.5 TH 6/8) gravelly s i l t loan, mottled, accumulation of gypsuo crystals) lying over gravel) on
top of the gravel light coloured gypsum powder.
123
Supl«
dspth
ID
Saapl.
nusbar
31-1
31-11
0-3
6-12
31-III
31-IV
25-30
50-55
31-»
80-85
E.3.P.
: 10 J
0,80
0,91
-
Band
silt
5O-2U
clay
THTT
~5576
61,1
50,0
5,7
9,0
20,1
»,0
8,2
8,2
32,7
38,6
29,0
26,0
8,7
8,5
2,5
1,6
1,6
0,8
29,9
29,9
38,3
35,4
Exchangsabl. bass« m./ico g
Organic o a t t . r
T.xtur» U.S.A.
Ca
««
2,36 2,20
Ba
SUB
os/1 CO g
lé,6
0,17
2Î73
2TT3
14,7
2,22 2,10
0,17
18,6
18,6
10,6
4,48 1,23
0,38
16,7
ypBUB
C/B
19,!
23,4
27,9
26,1
24,8
16,7
8,37
5,70 0,48
1,02
15,6
15,6
7,57
8,27 0,25
1,51
17,6
17,6
5 water extraot me/i00g
2,28
»Ï0*
cationa
«6
K
Ca
0,20
0,14
0,58 0,15
2,26 0,42
1,09 0,34
1 ,05
0,
0,14
0 ,79
0,
0,07 1,12
0,01 1,95
2 ,62
2,
0,15 0,17
0,42 0,11 0,12
6,54
4,10 0,55
0,69 0,24
e,5d
6,40 0,98
0,59 0,70 tr
3,52
96
78
tr
55
tr
2 ,89
2 , 64
tr
4,81
5, 05
tr
tr
0,69
0,64
tr
0,52
0,53
0,41
0,62
0,20
0,14
0,07
0,10
1,69
1,31
0,36
3,32
1,01
0,31
tr
tr
0,26
Chenlcal and D literal ogical analyses of tha clay f r a c t i o n (v 2n)i
Sample
Al O
F s ? 0 . MgO
50,2-
16,3
B,4
53,4
49,5
15,9
15,2
14,8
8 ,8
8 ,7
7 ,9
12,7
7, 2
Clay n i n a r a l s
Buab«r
31
31 I I
31 I I I
31 I V
51,1
58,1
11 V
5, 3
5, 0
4,6
o, 7
1
2,5
87,4
0, 6
0,
2, 3
4, 1
2,3
5, 1
7, 1
2,1
83,2
85,8
7
1,5
7
0, 6
2,
16 , 2
3,1
2,8
15 ,3
2,8
17 ,4
3,0
21 ,5
2,8
5, 7
5, 5
5, 9
7, 8
89,9
Chi
9 F
Chi
« F
« F
Chi
Cfal
9 F
S F
Ch«airal analyses of t o t a l s o i l saapl* (v2 ffla)i
Sampl«
nuab.r5,e
4,6
13,0 3,9
1,6
0,2
88,6
11,3
31 I I
49, 1
7,6
5, 6
89, 2
11, 1
23,
4
2, 1
7,0
1,4
0,1
86,
11, 1
24, 4
2, 2
31 I V
46, 6
7,6
5, 1
4, 9
5, 1
5, 7
0,1
45, 4
15,5
17,2
1,6
31 I I I
4 ,6
4,6
4 ,5
15,5
3, 8
1,2
0,1
84, 2
10,
25, 9
2,
31 V
46,
6
5.2
5, 1
4 ,4
14,5
5, 2
1,1
0,1
82, 2
1»,
25, 0
1, 6
Sanple
sand
2 mai-JOu
nunbar
18-1
18-11
18-111
18-IV
0-10
10-20
35-45
65-85
•>
5
Exchangeable baaaa ne/100 g
C/H
64,0
62,7
17 , 1
8,
24 , 0
11, 2
13, 5
72,7
16 , 1
9, Ü
8, 8
-
-
56,5
» ,0
8,
5
-
-
13,
5
o lay
'2H
9
3
18,
5
5
Organic n a t t a r
Textura U.S.A.
Sa.pl.
5
9
Ca
CacO,
18,4
23,1
23,6
26,8
0,80 0,10
Na
Sun
ma/100 g
24.7
2,67 2,72 0,09
30,2
30,2
22.8
3,24
28,6
28,6
20,6
4.05 1,41
0,11
26,2
26,2
12,6
4,06
0,10
17,4
17.4
2,53 0,04
0,52
; 5 watar extract na/l 00 g
cationa
0,30
0,14
-
0 ,12
-
0 ,12
0,42
1,04
-
0 ,31
9 ,47
1 ,06
Sa=pl.
nuaber
Saaple
"•.£">
en
10-20
26-111
25-35
50-60
26-IY
0,05
tr
0,08
0,72
O.Ji
0,19
0,03
0,01
0,06
0,î5
0,84
2,28
0,70
0,68
1,47
5,17
0,64
0,59
1,31
tr
tr
4,95
Texture U.S.A.
tr
57
0 , 59
0, 52
tr
tr
»07
tr
0,44
0 ,20
0,15
tr
0 , 13
2,97
0 ,60
1,05
sand
2mm-5Ou
silt
50-2n
Organic n a t t e r
5
5
11
,9
13 ,6
16 ,6
54,7
50,0
10
14 ,2
66,7
clay
<. 2u
19
31 ,7
33 ,4
17 ,1
C
S
Exchangeable ba»es ae/lOO g
0,90 0,12
,5
8 ,7
8 ,8
CaCO,
Hg
K
Ha
7,5
16,9
23,5
2,31
2,55
0,09
28,5
19,6
23,8
3,09
2,02
0,11
29,0
20,1
23,2
3,09
1,52
0,12
27,9
26,7
22,0
2,90
0,31
0,13
25,3
e, 8
1 t 5 water extract ne/i00 g
.Ï.3
Ha
C*
28 ,5
29 , 0
0,32
0,38
0,14
0,48 0,12
0,13 0,06
0,10
0,25 0,11
0,08 0,09
27 ,9
0,43
0,11
0,25 0,08 0,04 0,14
25 ,3
0,51
0,11
0,14
124
0,11 0,01 0,26
Sum
Sun
CO,
BCO.
0,79
0,53
0,75
0,52
0,51
0,48
tr
tr
0 ,64
0 ,52
0,51
0,52
*
gypeum
C/H
C.E.C.
»o/l 00 g
tr
tr
pH
gravel
26-11
0,48
0,34
0,52
2,16
0,51
0 ,48
Ca
Sua
Profil«i
31.
Ott« of o b . . m t ion. January 1966.
Locationi north-weat of Kajle.
Blevs-tioni 263 B.
Rsliefi
flat.
Xativ« vagatationt
scarcely grass and low shrubs.
Soil conditional dry to • l i g h t l y
Soil
aoist.
fauna 1 BOM aata.
Field c l a r i f i c a t i o n 1 ao{l)Lb.
Soil typ«1 Typlc Caloiorthld.
(A )
0-5
on
Dry,light y«llowi«h brown (lO TH 6/4) » l i t
hard platy atructur«f
(B)
^-20
o*
margins quickly
dry, light ysllowish brown (lO TH 6/4) t i l t
blockjr structural merging rath«r quickly
(K 21 )
20-45
lo*» with w r y f«w l a p i l l i ,
<>•
**y to «lightly noiat,
brownish yellow
blocky atruotur«, many «oft «bit«
containing l i t t l e
loaa with vary fa« l a p i l l i ,
(lO TB 6/6)
ailt
loaa with vary fa« l a p i l l i ,
lin« accumulation*t Barging gradually
45-65
CB
dry to alightly s o i a t , yellowish brovn (lO TB 5/6) clay loan with very f«« l a p i l l i ,
CB
dry to s l i g h t l y a o i s t , y«llo«iah brown {lO TH 5/6)
many aoft «hit« lia« accumulation«! a«rging gradually
lia« accumulation«) a«rging gradually
105-125
OB
«lightly hard cruably to «ubangular
Intoi
65-105
(K-,,)
slightly
poorly rootad, »lightly hard oruably to subangular
(K
blocky structura,
root«d,
intot
U22)
)
organic u t t r U l ,
intoi
alightly bard oruBbly to eubangular
intoi
loaa with fa« l a p i l l i ,
hard angular blocky atruotur«,
few aoft whit«
intot
dry to «lightly a o i s t , yallowiah brown clay loaa with fsw l a p i l l i ,
soft whit« lia« accumulation«.
Profils » 18.
Dat« of obs«rv*tiom July 1965. •
Location1 Haaret t«rrac«.
Elevstioni
248,4 a.
lativ« vegetation! short dry grass.
Parent aatarisli
loaay cover of Upper Pl«iatoc«n« Euphrates tarraca.
Soil condition«! dry.
Soil faunas worn track«.
Soil
surfacei
fox holes.
>i«ld olasaificationt AoLb.
Soll typ« 1 Typic Calciorthid.
(JL%)
0-10
CD Dry, T«ry pal« brown {lO TH 7/4) s i l t
eruably atructur«,
(B)
10-24
ca
dry, very pal« brown (lO TR 7/4) s i l t
blocky structure,
loaa, containing vary l i t t l «
organic u t « r i a l ,
locally a platy structur« near th« aurfao«; B«rging gradually
loaa, Containing very l i t t l e
few Una accumulation«( aerging gradually
(K 21 )
24-55
ca
dry, l i g h t , yellowish brown (lO TH 6/4) s i l t
U22)
55-102
cm
dry to s l i g h t l y aoiat, reddish yellow
organic «at«rial,
•
- p - r
poorly rootad, soft cruably to
loaa, alightly hard to hard granular to subangular blocky structur«, BOBS
intoi
(7.5 Tfi 6/6) a i l t y clay loan with soae gravel, bard granular to subangular blocky
structure, aosa clay-hunus accuBulation«,
102 ca and
to s l i g h t l y hard
intoi
clay-huBus accumulations, aany s l i g h t l y hard lim« concrstions; marging gradually
(ï,1 )
rooted, aoft
intoi
lin« accuaulations, aarging intoi
dry, strong brown (7-5. TB 5/6) s i l t y clay loaa,
coapact consistence,
occurrence of a pabble-cobble layer with lime
accuaulations under th« atone«.
Profile 1 26.
Data of observation1 auguat 1965.
Location 1 aouth of Ha«inaii.
El«vationi 297,5 =>•
Beliafi
flat,
low.
I>and ua«i cereal«.
Parent aat«rialt
loaay cover on Lover Pleistocene
terrao«.
Soil conditions! dry to alightly noiet.
Soil fauna1 very few wora tracks.
Field classification1 lOLb.
Soil typei Typic Calciortbid.
(* 1 t )
0-3
ca
dry, reddiah yellow (7.5 TB 7/6) o i l t
B«rging gradually
(* 1 2 )
3-10
ca
dry, reddiah yallow
structurel
loan, containing very l i t t l e
organic «At«rial, w«ll root«d, soft platy structurai
loaa, containing nry
organic aaterial,
intoi
(7.5 TR 6/6) s i l t
Berging gradually
littl«
well rooted, s l i g h t l y hard cruably
intoi
(B)
10-24
ca
dry,reddish yellow (7.5 TR 6/6) s i l t y clay loaa,
(K1 )
24-40
ca
alightly a o i s t , yellowish red (5 TR 5/6) s i l t y clay loam, poorly rootad «lightly hard blocky «tructure, clay-huaus accumulations,
faw lia« accuaulations! aerging gradually
(Kg)
4O-II5 ca
poorly rooted, soft
to alightly hard crumbly •truetur«merging gradually
intoi
a o i s t , y«llowish red (5 TB 4/8) clay loaa with soae fine gravel, very poorly rooted up to 55 cm, hard blocky
clay-humus accumulation«, nmny lia« concretions; marging gradually
structure,
intoi
U3)
II5-145 cm
s l i g h t l y a o i s t , yallowish red (5 TB 5/8) loaa with soae fine gravel,
C
I45-170 cm
s l i g h t l y a o i s t , yellowish red (5 TR 5/8) loaa with SOB« gravel! lying ovar gravel.
few lime concretions! Berging intoi
125
intoi
Saaple
suple
depth
Texture U.S.A.
•lit
clev
50-2|i <. 2u
47,5
22,2
48,4
32,7
46,2
39,3
39,6
38,0
mimbar
32-1
32-11
32-111
32-IT
0-10
20-30
40-50
70-80
7
30 , 3
-
16 , 9
-
14 ,5
13
22 ,4
EC
E. 3 . P.
0,66
0,78
0,00
4,13
Saapl«
1 •
xîo J
0,74
Ca
0*22
0,21
0,17
1.20
0,34 0,31
0,46 0,36
0,28 0,34
3,53 0,98
sample
d«pth
0-5
10-15
30-35
70-75
105-115
21,8 3,19 2,70
15,5 4,84 1,53
19,0 5,32 0,86
16,9 5,83 0,39
13,2 6,66 0,44
15 ,1
12 ,4
50,
1 ,5
11 ,5
44, 8
16 , 6
_
22 ,7
8 ,0
27,9
22,3
26,3
24,4
21,5
gravel
0,7
2
e
53, 3
0
N
0
0
25 , 3
eilt
50-211
anions
COj
BCO3
Sum
0,90
0,86 '
5,71
tr
0 .64
tr
0 ,65
tr
0.41
SI
\
0,20
0,20
2,47
0,60
tr
C/H
1,76
2,55
6,88
10,6
27,3
23,0
22,4
19,6
27,3
23,0
22,4
19,6
17,0
23,1
24,1
30,9
31,6
8 .6
8 ,4
e,4
0,86
1.97
4,30
5,16
5.67
1 i 5 vater extract me/iCO g
cations
e 3
EC
X 10
0,24
0,23
0,78
1,21
1,56
7 20
59
10 37
6
Ba 0
1 5
3
Ca
«g
0,10
0,10
0,28
0,65
1,20
47
0 , 32
1, 38
1, 07
3 , 84
0,
Sa
*
0,09 1,10
0,02 0,62
0,01 2,17
0,01 3,98
0,01 4,49
*
C
Sum
co3
1.76
1,06
3,84
5,71
1 ,2b
tr
1,02
tr
3,17
tr
5, 6 2
tr
9,54
8 ,15
tr
HCO,
Cl
0,56
0,45
0,34
0,36
0,32
0,40
0,24
1,46
2,63
2,54
"4
0,30
0,18
0,48
1,10
3,47
Exchangeable bases ma/100 g
*
HO,
0 ,02
0 ,15
0 ,69
1 ,53
1,62
c. E.C.
*
s
25,7
8 3
0,
20,3
14,6
13,1
74,5
54,5
25,2
8, 8
-
-
46,9
65,2
38,5
9, 3
9, 0
-
-
-
-
8, 1
-
-
• 5 water extract ma /too g
cations
Sa
Sum
»g
K
0,33 0, 20 1,03 2 69
1 42
0,11 0, 11 0,91
1 40
tr
0, 02 1,28
0,02 0, 01 2,29 2 56
2,92 0, 01 2,31 20 4
anione
Sum
Organic matter
p£
clay
<• 2u
50,7
1,13
0,29
0,10
0,24
15,2
0,18
0,18
0,18
0,82
CaCO,
8 ,9
23,6
Ca
0,71
0,50
0,38
0,18
0,05
0,06
0,01
2,21
2 0,10
C/S
CaCO,
7,2
25,9
28,5
31,6
29,6
18,5
gyps om Ca
0,02 14 8
-
13 6
tr
12, 0
11, 1
21,9
11, 1
1
,10
0,57
0,28
0,30
0,58
2,76
2,82
4,37
5,76
6,79
"°3
tr
tr
1,15 07T3 8,8
a,7
œ
21,7
Cl
,94
E.S.P.
27,9
22,3
26,3
24,4
21,5
2mn-50M
23,6
17,9
16,1
11,8
se/l 00 g
Organic matter
ola,
<2n
13,4
21,6
34,1
34,3
43,7
C.E.C.
me/100 g
sand
J
126
9 ,5
Sum
Texture U.S • A .
*
BC,
3,70
5,94
5O-2M
1 .5
EC
3,39
eilt
2• 5
E.S.P
-
8 ,5
0 , 38 0 , 04
0,20 0,15
1.13
0,07 0,24
0,06 0,22 0,90
0,12 1,43 6,06
67, 7
65, 8
0,24
0,44
1,13
1,26
1,22
S»mpl!
-
Sa
*
18 , 9
12 ,6
Exchangeable bas e s me/100 g
Sa
Sum
»8
K
1,80
0 , 90 0 , 11
8 ,5
SUD-
gypsum
5 • a t e r extract me/100 g
1
1 ,5
Ca
sample
depth
in
number om
0-3
42-1
42-11
3-14
42-11
22-32
42-IT 45-55
42-ï
75-85
8 ,5
CaCO,
22 , 0
Texture U . S . A .
eand
2mm-5Ou
number
3Ö-I
38-11
38-111
38-IT
38-ï
cations
»g
X 10 3
*
C/S
8 ,6
C.E.C,
Exchangeable baaoa pe/lOO g
Organic natter
ar
iona
Sun
CO,
HCO3 Cl
2,68
1,32
1,44
2,82
20,6
tr
0,53 0 , 3 3
tr
0,87
tr
0,90 0 , 2 5
tr
0,68 0 , 7 5
tr
0,22 0,96
tr
^4
1,18
0,30
0,20
1,21
9,3
SO,
0,64
0,15
0,09
0,18
0 , 14
Sa
»I
24
3 , 76
5, 61
6 , 12
5, 06
3,
2 ,57
2,49
1 ,16
0 ,53
0,38
0,37
0,52
1,39
2,23
0,58
Sum
21,0
20,4
20,2
21,0
17,1
me/100 g
21 , 0
20 • 4
20 , 2
21 . 0
17 ,1
Profil«i 32.
Dat* of observation) April 1965.
Location 1 south of Haxiaah.
Elevation) 297,4 • •
Relief) flat.
Land UMI vheat.
Parant natariali loan; cover on Lover Pleistocene Euphratea terrace.
Soil condition*) noiat to wet in th* topaoil.
FitId classification! AoLb.
Soil typet Typio Calciorthid.
(A )
(BJ
O-IJ
15-4O
(K )
4O-65
(Kg)
65-IOO
ca Wet, dark brown (7,5 YR 4/4) loan, rootad, friable cruably structure, fev lin«-aycelia| Barging gradually intoi
ca a o l s t , dark brown ( 7 . 5 TB 4 / 4 ) s i l t y clay loan, poorly rooted, friable granular to crunbly atructur*, lime-oyceliat merging
gradually iota 1
en moist, atrong brown ( 7 . 5 . YH 5/6) « i l t y clay loan, aubangular blocky atructur«, clav-humua accunulationa, aany l i a « myceliai
Barging intoi
en a l i g h t l y Boiat, yallowiah red (5YH 4/0) clay loam, aubangular blocky atructure, clay-huau« accunulationa, l i a « concrétion»,
Bottled.
Profilât 38.
Data of observation) June 1965.
Location* Haaret tarrac«.
Elevation) 262,8 B.
Relief) low, faintly sloping.
Native vegetation) grass ( s c a r c e ) .
Parent material) loaay cover of Middle Pleistocene Euphrates terrace.
Soil conditions) dry.
Soil fauna1 SOB* worn tracks.
Field c l a s s i f i c a t i o n ! AoLb.
Soil typ*) Çypic Calciorthid.
(*, )
0-5
(B)
(K,)
(KA)
C ca
CB Dry, l i g h t yellowish brown (10 YH 6/4) s i l t loao, containing l i t t l e organic material, 0-1 en s l i g h t l y hard platy structure,
5-19 ca dry, yellow (iO YR 7/6) s i l t loam, containing BOB* fine gravel,poorly rooted, « l i g h t l y hard cruably to «ubangular blocky
structur*j merging gradually intoi
19-50 cm dry reddish yellow ( 7 . 5 YB 6/8) a i l t y clay loaa, poorly rooted, fev scattsred brown mottles, hard subangular blocky to blocky
structur** aany white 1iB* accumulâtions and concr*tiona1 Berging gradually into!
JO—105 ca dry, strong brovn ( 7 . 5 ^^ 5/^*) a i l t y clay loan, few scattered brown a o t t l a s , hard blocky structure, very auch whit* l i a *
l i a « - n y c * l i a | merging intoi
I5O-2OO cm dry, reddish yellow ( 7 . 5 YU 6 / 6 ) a i l t y loaa, loose s t r u c t u r e l e s s , few gypsum c r y s t a l s ) lying on gravel.
Profile) 42.
Date of observation! January 1966.
Location) north-vest of Kejla.
Elevation) 261 a.
Relief! flat.
HatWe vegetation» grass and shrubs (scattered, height 30 cm).
Parent material! loamy cover on Kiddle Pl«latoc*n« Euphrates terrace.
Soil condition«! drV to slightly moist.
Field classificationt AoLbc.
Soil type1 Typic Caloiorthid.
(*, )
0-3
(B)
(Kj)
3-14
14-40
(K.)
40-60
many slightly hard whit« lin« concretions) msrging gradually intoi
CB slightly moist, strong brovn (7.5 YB 5/8) d a y loam, very poorly rooted (in cracks), hard angular blocky structur* with slight
tendecy to prismatic structure, very few l i s e accumulation»! merging rather quickly into)
6O-I5O cm slightly moist, dark brown ( 7-5 YB 4/4) loam, faintly mottled, bard consistence, structureless, gypsua crystal« in void« and
C 1c>
C
2cs
cm Dry, light yellowish brovn (1O YH 6/4) s i l t loaa, containing very l i t t l e organic material, poorly rooted, hard weakly platy
structurei merging quickly into!
cm dry, light yellowish brown (1O YR 6/4) « l i t loaa, poorly rootad, «lightly hard crumbly structure» margin« gradually intoi
ca dry to slightly moist, strong brovn (7.5 YH 5/8) s i l t loam, vary poorly rooted (in cracks), hard subangular blocky structure,
1
5°-200
ca
scattered( merging intoi
alightly moist, loamy sand to sandy loam, pockets of gypaua crystals or fine-cryatalline f i l l i n g up of void», mottling
Increases «lth depth, less gypsum at 2 a.
127
TABLE 3 0 . 5 : TYPIC CALCIOHTHIIISi LOAMY OH CLAYEY OF THE BALIKH REGIO».
sasple
e U.S.A.
in
nunber
cm
0-8
37-1
37-n
37-111
37-IÏ
*
gravel
_
2mm-50|i
9,8
83,4
6,8
3,8
78,1
18,1
8,3
34,0
17-25
42-50
65-75
EC
1 ,11
-
1 ,52
4 ,02
3 ,08
3 ,52
C
1,11 0,12
8,
Eich. ingeabla
bases me/100 A
C.E.C.
Ca
K
Ha
Sum
me/l 00 i
*
H
C/H
CaCOj
9,3
32,6
gypsum
-
«g
17,9
4,67
3,69 0,09
26,3
26,3
15.0
6,91
2,14 0,14
24,1
24,1
9,96
0,98 0,19
22,3
22,3
0,47
24,0
24,0
63,7
33,4
8,4
36,4
11,2
1.9
61,9
36,2
8,7
36,8
10.1
13.1
0,37
5 water extraot me/lOO g
xïo 3
-
clay
2,9
~5
0 ,70
PH
0
silt
50-2u
«g
0,23
0,44
0,60
0,62
0 ,58
0 ,19
0 .34
0 ,06
1 , 17
0 .88
0 ,66
0 .22
0 ,27
2 , 03
0 ,89
1 ,29
0 .04
0 ,97
0 ,55
1 ,10
0 .01
1 .27
3 , 19
2 , 93
0,77
1,76
2,44
2,41
tr
0 , 76
tr
tr
tr
0 , 81
tr
0,
tr
0 , 71
tr
0 , 81
tr
0 , 76
0,41
0,92
1,22
0 , 01
tr
0 , 43
54
Chamical and minaralogical analjaas of the clay fraction ( <- 2
Sample
Sio 2
ii 2
SiO 2
SiO 2
5
4, 2
Ho Chi
32, 7
36, 8
5, 7
6, 4
Do Chi* P*
I* + K
2,5
6, 7
5, 7
5, 7
28,
89 ,4
90 ,2
Xo Chi
P*
I** K* 9 P
1,9
88 ,7
6, 3
17, 4
2, a
Ho Chi
P " I* K* O. P
XgO
CaO
Ha 2 O
KjO
0,9
2,5
2,4
92 ,5
0 .8
2,8
2.5
0 ,8
2,6
0 ,8
1.7
Clay minerals
Total
number
37 III
57,4 17,1
4,1
3. 8
4 .6
5,7
37 I»
53,3 14,4
8,2
8 ,4
37 I
61,5 15,6
37 II
56,9 16,9
5,8
4,7
P * ~ T * K* « P
« P
Chemical analysas of total soil sample (< 2
Sample
37
37
37
37
I
II
III
IY
Sample
number
HgO
34,3
35,8
31,4
32,0
7,6
4,7
5,0
20, 4
4,1
77 .6
4,9
4,7
20, 5
4,1
1,4
1,6
0,1
6,7
0,1
78 ,4
6,8
4,6
20, 6
3,6
1,5
0,1
73 ,7
7,0
4,6
4,9
4,5
19, 2
2,6
1,7
0,1
71 ,7
8-Y
8-YI
S
S. P.
1.14
1,01
1,07
1,05
2,19
3,19
Toiture U.S.A.
sample
depth
sand
gravel
0-4
8-II
8-III
8-IY
5-10
13-16
25-30
45-50
75-80
•s
CaO
2mm-5On
pH
eilt
clay
5O-2M
<2u
66,2
14,0
8,3
59,4
23,6
8,4
-
0
14.1
56,2
27,7
8.4
-
5
6,6
13,1
56,4
30,5
8.5
-
15,6
47,1
37,3
8,2
-
7
17,2
42,7
40,1
8,5
-
0,2o 0,51
0,18 0,50
0,15 0,43
0,17 0,42
0,35 0,75
0,43 0,83
128
Ha
Sum
Sum
0,12
0,12
0,12
0,14
0,27
0,29
0 .09
0 .09
0T10
0 ,07
0 ,08
0 ,04
0 ,14
0 ,01
0 .56
tr
0 ,80
0,82
0,77
0,70
0,74
1,59
1,92
0,73
0,63
0,56
0,54
1,47
1,89
0 ,06
2,2
2 ,4
Bxchangeble basas me/100 g
C.E.C.
17.0
K
2 ,2
Organic patter
19,8
Xg
2,6
19,7
19,9
17,4
19,0
V
0 ,7
1 ,4
1 > 5 water extract me/100 g
cations
Ca
7,7
9, 2
7,9
7. 6
0,58 0,08
anions
CO3 HCO, Cl
tr
tr
0,59
tr
0,61
tr
tr
tr
tr
tr
0,55
0,53
0,45
0,42
tr
C/H
CaCO,
77T
40,5
39,7
41,8
42,1
42,2
43,2
SO,
0,10
tr
tr
tr
tr
0,25
0,48
0,31
0,31
HO,
0,04
0,02
0,01
0,01
0,46
0,66
gypsum
Kg
12,1
11,2
11.3
13,2
15,0
9,71
3 41
1,86
1,98
3, 79 1,56
4, 48 1,18
5. 00 0,50
5, 34 0,44
3, 44
ma/100 g
0,20
0,17
0,18
0,20
0,46
0,51
17,6
16,8
16,8
19,1
21,0
16,0
17 ,6
16 ,8
16 , 6
19 ,1
21 , 0
16 , 0
Profil«t
37.
Late of observatioai Hoveaber 1965.
Location 1 Hawïje, Balllch valley.
Elevatiom 305,3 n.
Beliefi
f Ut.
Istiv* vegetations bushee.
Land uset cereale.
Parent nateriali Ballkh alluviumSoil conditional dry.
Field c l a r i f i c a t i o n ! AoLb.
Soil typet Typlo Calelorthid.
(A^)
0-15
oa
Dry, light yellowieh brown ( i 0 TB 6/4) s i l t ,
containing l i t t l a organic material, poorly root*d, oedium bard subangular blocky
to crumbly structure; Barging gradually intoi
(B)
15 - 32
ca
(Kj,)
32 - 63
en
dry, yellowish brown (1O TB 5/6) e i l t loan, poorly rooted, nedlua hard subangular blocky structura, lie« accunulationst
dry, yellowish brown (10 TB 5/6) « i l t y olay loan, poorly root«d, bard blocky structura, l i s a concrationai a«rging gradually
(KJJ)
63 -100
oa
dry, dark yallowiah brown (1O TB 4/4) a i l t y olay loam, bard blocky atructur«, l i s a concretions. Deeper in the profile
••rging gradually intoi
intoi
silty
clay loan with fsv mottleai on 250 en blooage on clay.
Profile 1 8.
Itate of observation! February 1966.
Location1 aast of Mutlaq s i Ka'ahiah.
Elevation« 299,5 m.
Belieft
flat.
Land uaet carsala.
Parant aaterialt loaoy aaterial of fialikh terrace.
Soil condition»1 »lightly notât to dry.
Soil surface 1 ploughad.
Field c l a s s i f i c a t i o n )
AoL/Cl b.
Soil typet Typic Calciorthid.
(A^)
0 -
4
CB
Slightly «oint, strong brown (7.5 TR 5J/6) « l i t loam, poorly rooted, containing very l i t t l a organic aaterial, «oft crumbly
(A..)
4 -
11
ca
s l i g h t l y a o i s t , strong brown (7.5 TR f>/&)
atructure, locally platy atructurej n«rging gradually intot
s i l t loaa, containing vary l i t t l a
organic oaterial, poorly rooted, eoft crumbly
atruotura) oerging gradually intoi
(B)
11 -
19
cm
(k^)
19 -
41
cm
»lightly Boist to dry, strong brown (7.5 TB 5/6) s i l t y clay loan, very poorly rooted, soft crumbly to subaogular blocky
structura, few line spota) Berging gradually intot
dry, reddish yellow (7.5 TBf5/6) e t l t y clay loan, vary poorly rooted, hard blocky structure,many l l a e spota, faw clayhumus «ocuBulatloas; merging gradually intoi
(E 2 1 )
41 -
CK22)
68 cm
68 - 130
dry, strong brown (7.5 TR 5/6) s i l t y olay loam, very poorly rooted until 50 on, many clay-humus accumulations, very
hard blocky atructure, very auch lime concretions! merging gradually i n t o :
C,
130 - 150
C
1
2 ca
^ ~
20
°
cm
cm
c
"
dry, atrong brown (7.5 TR 5/6) a i l t y clay, clay-hunus accumulations, hard blocky structure,
few line spots! «erging intoi
vary dry, light yellowish brown (10 YB 6/4) s i l t y loan) «erging intot
T
*
r?
d r y t
l i g l l t
w
7*Ho iBh brown (iO TR 6/4) s i l t y loam, aottled,
few gypsum c r y s t a l s .
129
sampl«
deptb
Sample
nimber
34-11
-
25, 9
8,7
-
31, 6
8,5
-
25, 3
0 , 02 10,
23, 5
0 , 02
31,3
67,0
55,0
43,8
0
4,9
75,5
19,6
8,1
34-ï
85-90
xîoJ
0,45
1,7
1,2
60-65
EC
8,5
0
34-111
34-IV
14,9
1 i 5
cati ns
EC
5
x,03
0,20
Ca
ne
0,60
0,05
Ha
Sum
0,26
0,05
0,61
1,52
0 ,24
1 , 01
1,12
4 ,87
0
,18
0,
48
0 , 26
-
0 ,36
0,
34
0,
33
0,03
0,02
6, 6 0
1 ,28
0,
91
1 , 13
0,03
10, 20
4, 2 6
13,
5
8 , 81
0,07
10 , 1
Sun
C0
anio IS
uco,
29
I
Sample
depth
44
I
44
II
45 I
46 I
46
f
I I *
47 I
*
x 10
16,9
32,6
0,15
0,85
32,0
32,0
17,7
19,8
1,27
1,87
3Î*,2
31,2
1,33
2,15
31,3
31,3
SO
0,74
0.04
0,02
0,73
tr
tr
1 , 81
75
1, 86
0,83
1,02
tr
6, 94
6, 78
0,68
2,69
3,35
0,27
5i49
32,
0,
5
34, 5
0,01
28,6
0,06
0,10
TERRACE REGION.
C.E.C.
ne/100 g
18,0
8, 0
o, 99
0 • 08
12,4
53,2
-
1,3
-
8, 3
0 , 80
0 ,11
7,3
-
38,7
57,4
54,8
3,9
5,6
8, 5
0,
85
0 ,12
7,1
24,0
8, 1
0 , 86
0 ,10
8,6
21,8
-
14,2
1,89
49,3
60,6
24,5
8, 3
33,4
-
14,1
13,9
8, 2
2,05
1,23
30-40
25
39,6
26,2
0-10
17
25,5
5
8, 0
K
«g
Ha
Sum
93
0,
. 5 *ater extrac t me '100 g
c a t ions
0 ,11
23,4
22,0
tr
43,7
-
10,3
8,5
18,5
13,6
1,83
1,03
1,78
1,73
0,22
0,09
22,
3
22,3
16,
5
7,75 0,74
14,3 2,10
1,81
0,10
10,
4
16,5
10,4
1,33
0,30
0,18
0,27
17, 9
16, 7
16,7
23,9
0,09
2,74
0,27
0,18
16,
5
20,
9
0,99
0,55
17,a
0,96
1,01
16,7
1,62
16,5
20,9
0,86
1,64
an ions
Sum
1,18 0,17 0,10 0,07
1,52 t,43
1,06 0,12 0,18 0,10
1,46 1,39
16,2
5,99
6,87
MO,
tr
59,8
Ca
1,17
2,66
50-2 n
2,
,48
16,9
32,6
45,5
38,2
25
,27
8, 02
0,38
33
5-10
,31
4
1,85
0,17
22,2
0-10
3
16, 0
7,90
10,7
15,0
27, 2
27
-5
3
Exchangeable bases ne/100 g
30-40
EC.
21,
• ilt
gravai
0-10
0-10
7,15
Cl
3
TABLE 3 0 . 6 : TYPIC CALCIORTHIDS; LOAMY OVER FRAGKEHTAL OF THE
number
28,0
g
X
-
sample
9,0
j./lOO g
8,7
82,6
0,8
0
C.E.C.
*
CaCO,
C/H
2,5
15-22
36-40
Exchangeable bases me/100
Organic matter
Texture U.S.A.
sand
Bilt
2no-50n 50-2U
93,3
3,9
gravai
C0
3
0,67 0,86 1,68 19,2 18,7
,17
0,59 0,10 0,09 0,18
0,96 0,93
,25
0,76 0,09 0,12 0,09
1,06 1,19
,31
1,02 0,12 0,01 0,29
1,44 1,51
,27
0,97 0,11 0,26 0,05
1,39 1,26
HCO,
Cl
0,91
0,58
0,21
0,92
0,64
0,53
0,83
tr
tr
SO
0,45
tr
tr
BO
0,49 0 , 03
0,80 0 , 01
18,0 0 , 03
0 , 01
0,53 0 . 02
0,91 0 , 07
0,41 0 , 02
tr
tr
tr
TABLE 30-7: TYPIC CALCIORTHIDS; LOAMY OVER SANDY GYPSUM.
_
,
Sample
6
sample
depth
.*
Texture U.S.A.
«ilt
5O-2ii
1*0-10
23,5
23,3
6 I I * 30-40
pH
clay
*.2(i
H
Organic nattai
2°
61,3
15,2
8,5
61,5
15,2
8,4
Exchangeable baeea me/100 g
C/N
me/l00 g
CaCO
0,55 Q07
46,6
19,0
1,30
1,47 0,21 22,0
22,0
47,7
19,2
1,09
0,72 0,24
21,3
1 i 5 . ater extra t me/100 g
u.s . p .
ca t i ons
x 10
0,
96
1 . 12
3
unions
Ca
«g
0 ,72
o, 0 8 o, 07
0 , 09 o, 02
o, 17
o, 2 4
130
1.04
K
Sum
co3
HCO3
Cl
92
o, 77
tr
0,
53
tr
1 , 22
1 , 13
tr
o, 45
tr
»a
Su.
0,05
0,
0,07
C.E.C,
S04
o, 2 1
o, 6 2
HOj
0 , 03
o. 0 6
21,3
Profil« > U.
Dat« of obo«rvationi BOT«ob»r 1965Location! north of the v i l l a g e Tal • • Sauen.
Elevationi 264,5 • •
B e l i e f ) s l i g h t l y undulating.
Land u««i cereal«.
Parent material 1 Balikh alluvium.
Soil conditioni dry to « l i g h t l y « o u t ,
*-
Soil surface) ploughed.
Piald c l a a « i f i c a t i o n ) AoL/Cl be.
Soil typet Typie Calciorthid.
(i )
0
-
10
co
Dry, yellovinh brown ( i 0 TH 5/6) s i l t , containing l i t t l e organic n a t e r i a l , poorly rootad, »oft subangular blocky structural
(B)
10
-
28
cm
(K 2 )
28
-
45
c»
(K )
45
-
68
cm « l i g h t l y a o i « t , dark tiro«n (7-5 *H 4/4) « i l t y c l a y , fov clay-huau« accumulation«, poorly rootad, hard blocky «trueture,
narging gradually intot
dry, yellowiih brown (1O TR 5/6) a i l t loam, containing l i t t l e organic matarial, poorly rootad, «oft »ubangular bloclcy^
atructur«, f«v lin« accumulâtionaf Berging'gradually intoi
dry to « l i g h t l y a o i a t , dark brown (7-5 ™ A/A) c l a y , vaakly Bottled, yary fa¥ clay-humus accumulation«, poorly rooted,
e l i g h t l y hard eubangular blocky structuf«, fav l i n e accumulation« and concretion«1 «t«rging gradually intot
li&e concretion«, few pedogenetic gypnun-accumulation«) merging gradually intoi
C
«S8 - 100
cm
« l i g h t l y moiat, dark brown (7-5 YR 4/4) « i l t loam, fev clay-humu« accumulation«, hard bloclcy «tructure, « - y « t a l l i n « gypaum
aceumula t ion« «
Pr»fil«i 29.
Data of obs«rT*tiont Januari 1966.
ElcYationi 276 m.
Baliefi high, medium «loping.
Kative regetatiom graee.
Far*nt material 1 recant aaolic loan underlain by Pleistocene gravel.
Soil condition«) dry.
Pi«Id c l a s s i f i c a t i o n ) C3L.
Soil type 1 Typic Calciorthid.
IIC
10 ca
and deeper
Profilet 44.
Dat« of obaerratiom March 1965.
Location) north of fiaqqa.
Elavationt 2^4 m.
Rallefi high, medium «loping.
Native veg«tationi grass.
Boil conditions) dry to s l i g h t l y noi«t.
Field c l a s s i f i c a t i o n ) C3L.
Soil typ«1 Typic Calciorthid.
coa platy «tructurat merging gradually intoi
(B)
10
-20
cm
dry to « l i g h t l y moist gravelly s i l t loan, soft weakly developed crumbly stri
and deeper
Profilei 45.
l a i « of obeerrationi March 1965.
Parent material! recent a e o l i c underlain by Pleistocene gravel.
Soil conditions! dry.
Soil typet Typic Calciorthid.
(A.)
0
-
10
cm Dry s i l t loam, containing l i t t l e organic matter, soft weakly developed crumbly structura, upper cms. platy structure;
(B)
10
-
22
cm
c
dry s i l t loam, «oft weakly developed crumbly structure, lime mycelia; underlain by)
* and deeper
131
S*Bple
Texture U.S.A.
Sample
depth
sand
2mn-5Ou
gravel
nunber
1,
10-20
17-1
17-11
35-45
17-IH 55-65
17-Iï 110-115
3
0
0
1 , •>
Organic p a t t e r
silt
clay
5O-2M <2U
C/H
16, 0
59, 6
24
,4
8,6
9, 3
9, 8
S8, 1
52, 0
63, 6
_
38 ,7
8,4
-
26 ,6
_
8,1
-
0,45
gypsun
Ca
Kg
E. S. P.
me/1 CO g
Sum
0,36
5,0
24,4
22,5 4,07
-
-
30,3
25. 5
5,23
0,
72
0 ,28
31 ,7
31 ,7
-
-
24,5
23, 0 4 ,07
0,
34
0
,33
27 ,7
27 ,7
1,19
-
-
4,0
19. 0
0,
ia
0 ,11
22 ,7
22
,7
0,49
0,09
8,1
C.E.:.C.
e/100 K
Ha
1,42 0,10 28,1
45
0,88
5 vatep extract ae/lOO g
cations
Ka
Ca
0,71
2,31 0,54 0,07
0,87
2,14 0,68 0,01
1,04
3,17
0,42
Cl
SO,
U
3
0,661,970,12
3,51
Sus
3,79
IX.
3,69
0,75
0,46
0,29
5,49
2,50
16,4
1,98 0,01
1,73
20,1
19,9
0,31
1,31 18,2
0,12
4,42
2,48
19,3 2,54 0,02
0,99
22,9
21,6
0,22
0,27 21,1
0,02
Sample
39-1
39-11
Texture U.S.A.
Sample
depth
in
nuabep
3,87
gravel
2,70 0,06
Organic natter
silt
5O-2u
clay
-.2n
Exchangeable baeos me/100 g
sypeum
CaCO,
C/H
Ca
.e/100 i
Hg
0-8
1,5
34,9
57,2
7,9
9,0
0,90 0,11
8,2
20,3
19.8 2,04
1,38 0,08
23,3
10-20
2,5
32,1
53,4
14,5
9,1
0,39 0,05
7,8
25,4
17.9 2,22
1,01 0,10
21,2
23,3
21,2
0,34
0,47
0,33 1,02
21,1
21,1
4,83
23,9
23,0
5,52
0,22
39-111
35-45
5
19,0
48,8
32,2
9,1
35,6
16,0 3,72
39-1»
65-70
2,5
19,3
42,3
38,4
8,5
29,9
17,0 5,37 0,23 1,32
23,9
21,0 1,75
23,0
39-T
67,3
5
85-95
2,3
cation«
Ha
5,99
0,39 0,02
0,04 0,36
0,81
0,16
0,45 tp
0,03 0,36
0,
0,78
0,58 0,01
0,01 2,74
3, 34
2,18 0,97
0,01 6,79
1,85
9,48
2,88
20,5
1,77
0,04 3,91
Sample
depth
number
40-1
40-11
Sua
0,13
11,4
Sample
Sum
63,8
10,5
52,9
10,5
8,1
8 ,8
6
25,6
61,3
13,1
8,9
59,3
50,6
17,2
29,2
8 ,8
8 ,9
20-30
2, 5
40-50
2,
5
23,5
20,2
40-ÏI
75-100
1,
5
29,7
HO,
0,53
1,74
0,75
0,14
0,37
5,74
2,47
2,25 21,a
0,28
tr
0,15
Opganic matter
25,7
36,6
40-V
0,04
tp
0,11
0,11
0,24
1, 5
6
40-IV
SO
tr
S ,86
24 ,5
ollt
50-2U
40-111
Cl
3,16
Texture U.S.A.
8-14
15-20
an ion»
HCOj
,72
Band
2aa-5Ou
gparel
0-8
9, 95
26, 2
3
0,00
0,61
0
84
C0
57,9
Ca
6,30
21,8 1,53
1 ,86
0,04
07
-
6
22
,5
1 «32
0,07
-
22
,9
1 ,22
0,09
-
-
-
24 ,5
16,5 1,77
16,5 1,84
15,9 2,23
l ,12
-
-
-
29 , 1
1 ,86
0,18
0,
44
-
0,
7, 9
gypoum
8,81
a lions
HCO,
Cl
so.
0,32
1,23
0,18
0,19 0,11
1,71
1,53
tr
0,75
tr
0,75
0,03
0,17
0,61
0,07
0,07 0,14
0,89
0,64
tp
0,64
tr
tp
tr
0,18
0,49
0,13
0,05 0,17
0,84
0,56
tr
0,56
tr
tr
tr
0,18
0,51
0,13
0,04 0,21
0,89
0,56
tr
0,52
tp
0,04
tr
0,33
0,43
0,14
0,02
1,14
1,73
tr
0,51
0,54
0,42
0,12
2,85
3,19
0,17
1,31
9,08 13,8
tp
0,62
8,65
2,79
1,05
132
me/100 1
17 ,6
0 , 13
Sum
00,
1,59
Ca
9.«
27
Sua
13,1
C.E.C.
C/H
1,
8,4
>a
Exchangeable basée ae/lOO g
*
CaCO,
1 1 5 vater extp act me/100 g
cations
Mg
K
0,18 0,05
HO,
Mg
14,4 3,65
15,1 2,91
25 , 2
19 ,7
25,2
19,7
0
19,7
0
0,09
0,10
19 ,7
19 ,3
19,3
20 , 0
20,0
0,47
0,50
0,11
18 ,3
18,3
0,60
0
Profil«i
17.
Dat« of observation* July 1965Location1 Haartt terrace.
El «rat ion 1 249»8 • •
Belief! f l a t
Land usei
to faintly oloping.
irrigated cotton plant« ( 60 cm high).
Parent material1 loamy cover on Upper Pleietocene Euphrates terrace.
Soil condition«! moist to wet (irrigated 4 day« ago).
Pi«Id c l a s s i f i c a t i o n ! AgoLbcr.
Soil typei Typio Calciorthid.
(A,, )
25
cm
(K_)
25-
0 -
48
cm
Hoist (0-2 cm dry), dark yellowish brown (1O TK 4/4) a i l t loan with «one fine gravel, poorly rooted, oontaining black
noiat to w«t, dark, brown (1O YH 4/4) « i l t y clay loam, weakly mottled, «oft cmably to blocky etructur«, poorly rooted,
C
46 -
88
en
wet ( on 83 cm groundvater owing to an underlying impermeable layer), dark brown ( i 0 TB 4/4) s i l t loam, mottled,
organic material, «oft cruably to granular structure) merging gradually intot
soft
blocky struoturej merging quickly intot
II C-
&8 - 113
cm
very wet, dark brown (1O ÏR 4/4) « i l t y gypsun «and, strongly mottled, conpact consistance.
Profil«1 39Date of observation! July 196$.
Locationt Haaret terrace.
Elevation) £51,2 m.
fielieft
flat
to faintly undulating terrain.
Betiv« vegetation! short dry grass and whitish fungi.
Parent material! loamy cover on Upper Pleistocene Euphratea terrace.
Soil oonditionsi dry.
Soil s^ffface 1 a kind of desert pavement i s represented by email gravel and stones.
Field c l a s a i f i c a t i o n i
A OLbc.
Soil type! Typio Caloiorthid.
(A )
0
-
8
cm
Dry,very pale brown ( i 0 TB 7/4) s i l t loam with some fine gravel, poorly rooted, very l i t t l e organic material,
«oft
crumbly «trueture s l i g h t l y platy no ïir the surface ] merging CT&iluAlly intot
(B)
8
-
23
cm
dry, very pale brown (1O TB 7/4) s i l t loam with some fine gravel, containing very l i t t l e organic a a t e r i i l , hard crumbly
(K )
23
-
62
cm
dry, l i g h t yellowish brown (1O TB 6/4) s i l t y clay loam with «orne fin« gravel, hard granular to blocky structure, many
(K )
62
-
73
cm
dry, brown (7-5 TR 5/4) « i l t y clay loam with some fine gravel,
to granular etrueture, very few lime accumulation»! merging gradually
intoi
weakly a o t t l e d , hard blocky structure,few
lime
aocunjulationainerging quickly i n t o :
IIC
73
-
106
cm
dry, l i g h t yellowish brown (1O TB 6/4) gypsum sand with intercalations of cobble and gravel layers, gypsum beard«
under the stones.
Profile)
40.
Date of observation! June 1965.
Location! Hanret terrace, Hamret Balasim.
Elevation! 253 m.
B«liefi undulating, on the slope of a depression.
Dative vegetation) short dry grass, also whitish lichnen.
Parent material) loany cover on Upper Pleistocene Euphrates terrace.
Soil ourfacet stones on s o i l
surface.
Soil faunat 0-40 cm few worm tracks.
Field c l a s s i f i c a t i o n ! A lLbc.
Soil typei Typic Calciorthid.
(Aj)
0
-
8
cm
Cry, l i g h t yellowish brown (iO TB 6/4) s i l t
(B)
8
-
14
co
dry, very pale brown (1O TB 7/4) s i l t loam with some fine gravel, » e l l rooted, s l i g h t l y hard crumbly to granular structure»
loam with some fine gravel, containing l i t t l e
organic material, well rooted,
(K..) 14
-
23
cm
s o f t crumbly structure; merging gradually intoi
dry, very pale brown (10 SB 7/4) s i l t
loam with some fine gravel, well rooted, hard granular structure) merging gradually
intot
(K 12 ) 23
-
31
cm
dry, l i g h t ycllowUh brown (iO TE 6/4) s i l t
(K„)
-
73
cm
dry brownien yellow (10ÏB 6/6) clay loam, l o c a l l y intercalations of gravel, poorly rooted up to 60 cm, hard subangular
loam with some fine gravel,
1 c m ) , s l i g h t l y bard granular structure) merging gradually
31
poorly rooted (aleo old roots with a diameter of
into)
blocky structure, aany lime concretions] merging into)
IIC
1C,73
- US
CD dry very pale brown (1O TB 8/4) gypsiferous loam, very hard consistence! merging gradually
IIC 2 115
- 205
cm
intoi
dry, yellow (10 YB 7/6) gypsum.
133
Saaple
nuober
43-1
43-11
43-111
43-IV
43-v
Sample
depth
in
cm
0-5
7-12
20-30
50-60
70-80
Text ure U S.A.
XÔ^
">3
C.
0,36
1,93
Band
graYel
2,5
1,6
2,8
4
0
cations
Mg K
0,05
0,09
21,3
28,5
40,9
Sum
0,08
2,15
0,17
0,98
0,02
0,02
0,10
0,96
0,05
tr
0,27
2|38
0,49
1,65
0,19
tr
0,78
2,90
2,24
0,01
0,34
17,1 0,17
1,4
lia
0,24
Or
Clay
<.2o
silt
2mm-5Ou 50-2U
33,7
64,9
23,3
55.4
20,4
51,1
42,0
17,1
31,7
ganic nattar
pH
*
C
0,63 0,10
SS
6,-.
8,6
8,4
8,4
8,1
-
Sum
C 0,
Exchangeable baaes ma/100 g
*
CaCOj gypsum
tr
29,5
30,8
32,4
28,5
6,4
6C,6
C/H
6,3
-
«mon«
HCO. Cl
SO
Kg
K
Ka
0,07
0,15
0,29
0,42
0,05
Sum
25,6
25 ,9
25 ,9
21 ,7
19 • 0
me/l 00 g
25,6
25,9
25,9
21,7
19,0
Ho.
1,46
1,95
1,12
1,28
2,62
17,6
Ca
21,8 0,76 3,01
22,6 1,01 1,91
24,0 1,16 0,48
19,8 1,20 0,29
18,5 0,30 0,15
C.E.C.
0 ,94
1 ,31
tr
tr
2 ,64
tr
0,50
0,46
0,40
0,16
tr
18 , 0
tr
0 , 44
0!,25
0 , 45
1, 62
0, ,29
tr
0 , 15
0 , 33
0 , 15
0, ,25 17, 4
TABLE 3 0 . 6 : TYPIC GYPSIORTHIDS.
Sample
number
30-1
30-11
3O-III
30-IV
30-V
30-VI
Sample
depth
in
pH
Texture U.S.A.
'aval
0-5
116
8-13
20-30
2
1, 4
0, 8
35-45
55-65
80-90
0, 8
0
Band
2 mm-50li
26,7
23,9
20,7
45,8
59,0
55,7
s i l t clay
50-2(i *.2u
60 ,7
4,6
66 , 0 10,0
67 , 6 11,7
B
Organic natter
Exchangeable baaea ma/lOO g
2°
C/H
CaCO,
-
31,4
34,2
3 0,
8, 3
8, 1
8, 3
8, 6
-
35,5
15,8
-
4,7
8 , •>
-
7,0
gypsum
ie/100 i
«g
13,7
11,8
5,S7
4,69
4,67
tr
0,20
53,0
65,4
55,0
0,31 3,79
0,68 3,41
1,38 2,82
0,o4 0,42
0,76 0,27
1,28 0,39
0,14
0,23
0,39
0,04
0,09
0,19
1 I 5 water extract ne/100 g
ECe
X 10-"
0,63
1,26
2,38
0,56
1,55
2,91
2,72
8,60
6,80
6,40
6,40
6,00
«g
0,56
1,14
2,12
3,74
2,66
3,48
1 ,86
3 ,10
0,06
0,27
9,22 1,83
17 ,7 2,45
17 ,7 3,38
18 ,7 6,08
0,19
0,25
0,23
0,09
0,05
0,06
3 ,15
6 ,03
0,67
2,78
2,29
5,91
2,49 13,8
2,09 22,3
3,05 24,2
5,11 30,0
tr
tr
13 ,3
tr
22 , 0
tr
24 ,5
tr
29 ,7
tr
0,48
0,39
0,29
0,16
0,11
0,16
0,25 2.37
2,54 2,31
2,35 9,60
1.72 19,5
2,50 21,1
4,66 23,3
0,,05
Oi,79
o,,84
0,.65
0,,81
1,,60
Chemical and mineralogical analyses of the clay fraction (< 2 M ) •
Sample
number
SiO,
30 I
54,4
55,6
52,1
46,3
54,4
51,5
30 II
30 III
30 IV
30 1
30 VI
17,3
15,8
15,1
13,0
12,6
11,6
4,3
8,2
6,6
7,0
6,7
5,9
MgO
CaO
Ha 0
4,9
5,7
4,7
5,5
1,8
1,8
0,4
0,5
0,6
4,0
1,5
4,6
1,8
0,4
0,5
5,5
2,5
3,1
Total
2,4
2,3
2,2
1,9
1,3
1,4
65,4
88,5
81,8
83,2
80,8
79,9
Clay »inerals
5,4
6,0
5,9
6,1
7,4
7,6
33,6
18,2
21,2
17,9
22,1
23,8
Chi
Chi
Chi
Chi
Chi
Chi
6,3
3,0
3,6
3,0
3,0
3,1
K « P
It 0. T
K <J P
K « P
K « P
It « P
Chemical analyses of total soil sample (t 2 mm )t
Sample
number
30 I
30 II
30 III
30 IV
30 V
30 VI
CaO
45,4
41,2
35,8
13,1
13,4
15,4
134
7,3
7,8
6,3
3,5
1,9
1,6
478^ 4,4
5,0
3,6
4,4
3,9
1,2
2,3
1,3
2,9
1,6
5,6
17,2
19,2
20,3
28,9
27,7
26,2
"•2°
~3"7<!
2,6
15,2
4,9
4,9
3,9
1,4
1,4
1,3
0,5
0,4
0,4
KnO2
Ö7I
0,1
0,1
0,03
0,03
0,03
Total
84,2
80,9
87,3
54,4
52,5
54,7
10,6
9,0
9,8
6,4
12,4
17,1
25,2
22,1
22,1
31,1
27,9
25,6
2,4
2,5
2,3
4,9
2,3
1,5
22,3
18,2
16,4
7,17
5,81
6,53
22,3
18,2
16,4
7,17
5,81
6,53
E.S.P
0,2;
0,58
1,12
1,94
0,26
Profilât 43.
Data of observation! February 1966.
Location1 vaat of Hai'zila.
SI«Tition1 292,5 n.
Belief! flat.
Hâtive Tagatatiom short graeeee (acattered).
Parant nuitariali valley f i l l in Lower Pleistocene proluvial gypsua dapoaita.
Soil condition»1 dry to slightly nolat.
Field clasaifieation» agOlb.
Soil typai T^pic Calciorthid.
(A1)
0 -
10 en
(B)
10 -
15 en
(Kg)
15 -
40
(K-)
40 -
70 ca
IIC
'° ~
c»
10
°
Slightly »oist, etrong brown (7-5 ÏH 5/6) s i l t loao, containing l i t t l e organic material, rooted, crumbly atruotura,
locally a slightly hard platy atruotura at tha aurfaca; margin« gradually intoi
•lightly aoiat to dry, atrong brown (7-5 TH 5/6) a i l t loan, containing vary l i t t l e organic Batarial, rooted, elightly
hard to hard crumbly structura, very fa« line accumulation«! merging quickly intoi
CB drj, atrong brown ( 7.5 ÏH 5/8) clay loan, poorly rooted, elightly hard to hard subangular blocky atructure, Tery much
CB
aoft vhitish 1ime accuBulat iona 1 Barging ^âdually into 1
dry to slightly moiat, atrong brown (7.^ TB 5/8) s i l t y clay, vary poorly rootad, hard angular blocky atructure, aany
l i s a accumulation» from 40 to 60 cm, number of lima accumulation» decreaaing from 60 to 70 CB| merging quickly intoi
Doist
' T*r*r P*1* brown (10 ÏS 7/4) gypaum powder, mottled, alightly hard conaiatance.
Down to 150 cat gypaumpowder becoaaa mora mottled, loam contant ia increaaing dovnwarda.
Profilai 30.
Data of obeervatiom February 1966.
Location1 eouth-south weat of Herjan.
EleTatiom 294 a.
Beliafi flat to faintly eloping.
Bative vegetation) short grasses scattered.
Parent material! Lover Pleietocene proluTial gypauo depoaita.
Soil conditional dry to slightly nolet.
Field claaaificatiom C (b)r.
Soil type 1 Typic Oypaiorthid.
(*n)
0 -
(a]2)
5 - '5
(K)
II Cf
II C 2o>
II C ^ s
5 ca
Dry, yellow (1O TB 7/6) s i l t loam with a orne fine grarel, containing l i t t l e organic material, rooted, alightly hard platy
structure, merging quickly intoi
cat ^J to alightly moist, redaish yellow (7.3 TB 6/6) s i l t loan with aoae gravel, containing very l i t t l e organic Batarial,
15 - 30 ca
rootad, alightly hard crumbly structure, vary few lime eccumuletionsf merging gradually intot
dry, atrong brown (7.5 TB 5/8) gypaifarous s i l t loam with some fine gravel, rooted to poorly rooted, hard aubangular
blocky structure, line concretions) merging gradually intot
OB dry, yellow (1O TB 7/6) loamy gypaua aand, poorly rooted, tendency to hard angular blocky structure, mottling) merging
gradually intoi
45 - 70 ca dry to alightly moiet, reddiah yellow (7.5 TB 7/6) gypaun aand, hard consistence, etructureleaa but cemented, mottling)
aerging quickly intoi
70 - 90 em coarse gypaua sand with clay, hard conaiatance, caaantad.
30 - 45
135
daptn
la
aand
! 2BD-50M
*
mtabar
CD
10-1
1-6
0
1.5
10-11
30-35
0
55,5
EC(
BC
pH
H-O
allt
clajr
50—2M * 2 P
90,1
Exchangaabla tel aa aa/lOO g
Organic nattar
T«xtur« U.S.A.
Saapla
C
1Î5
8,4
*
S
C/H
CaCO,
gypnua
18,8
0,19
1,29 0 , 16 8,1
8,1
fl
47,6
6.9
.°
C.S.C.
Ca
•g
K
la
34,8
0,27
1 ,65
0,40
37,1
37,1
1,08
12,4
0,25
0 ,48
0,22
13,4
'3,4
1,64
SUB
S.S.P.
oa/lOO g
1 t 5 vatar •xtraot ma/100 g
2,22
2,84
Sampl«
auabar
12-1
12-11
0,72
2,22
t n i ons
oationa
»g
K
Ca
3,82
18,9
Ba
0,09
0,09 0,07
0,31
0,09 0,06
Sun
Sua
4,07
4,02
19,4
•and
2aa-5Ou
grave
CD
0-5
o
15-20
0
»Ht
5O-2u
ICO,
Cl
0,23
0 , 25 18, 3
tr
pH
Exohaagaabla
C/B
B
1 ' 5 C
7,7
1,49 0 . t7 8,8
8,0
23,9
44,2
0,16
Org.u i l 0 »attar
i
cl*/
<.2n
•°3
»4
tr
18,9
Taxtura U.S.A.
3*apl«
dapth
la
C0 3
i 5 vatar axtraot na/lOO g
cationa
Sum
Kg
E
Sa
Sun
*
CaCO,
20,9
*
orpaua
5,4
62,5
10,1
tea a
Ca
>g
23,3
11,1
1,06 2 42
0,79 0 31
.a/100 g
Ia
«
0,31
0,16
Sua
C.I.C.
•a/100 g
E.S.P.
27.1
1,14
12,4
1,29
27,1
12,4
1
EC^
Ca
2,86
3,80
Saapla
16,2
2,30
2.32
18,6
0 39
0 42
0,35 0,08 17,0
0,10 0,25 19.4
%
aaod
2nu-5Ot
CD
13-1
13-11
O-5
0
0
13-III
J3-IT
25-3O
60-65
100-110
E.S.P.
BC #
2,24
x 10
2,78
4,80
5,26
1,74
6,20
1,03
4,08
HCO3
Cl
»4
H
16,5
tr
19,1
tr
0» 47
0 21
tr
0, 25
15.7
18,0
0,33
0,67
Taxtiira U.S.A.
Saapla
daptn
in
8,2
8,1
-
18 ,1
3,77
19 ,0
Î.58
Ï,18
8,1
0
.10
W»
2 ,6
2
6,6
0,66 0,10
-
-
abl a
H«
20,9
8,0
37,5 16 , 2
74,9 2 ,23
0
23
13,7
71 ,6
5 ,47
1
34
tr
»aa*a na/lOO g
K
.a
Sua
1
0,18
17,5
4.17
15
1 54
0 18
0,17
0,16
7,15
C.E.C.
»a/100 g
17,5
4,17
7,15
-
-
ani< na
HCO.
0,36
tr
0,17
tr
0,16
co 3
Cl
0,25
tr
0,60
1,10
tr
.6
c
G rp*U B
C/B
B
C
7,8
18 ,2
ta
17 .5
ï,26
?.42
Sïoha
i
1^ - «at« r axtract na/lOO g
ca t l o aa
SUM
K
Ba
ïum
M«
0,24 0 , 2 2 0,06 16,0 1 ,6
0
,
1
0
0,86
0,47
20,4 20,4
2,08 0 ,90 0,79 20,0 2 ,4
3C
°3
Orgimie mattar
pH
V
el
-2 1
18,5
46,6
45.6
56,5
0
0
3
allt
50-2M
DB
C03
0,13
tr
"4
16 , 9
19 ,4
0,05
0,64
19 , 7
0,90
20 ,1
2,23
*°3
TABLE 3 0 . 9 : TYPIC CAMBOBTHIDS OF THE VOLCAHO REGION.
Taxtura U.S.A.
»-PI.
&uab«r
aaod
2a«-5O»
41-1
41-11
0-6
6-17
41-111
30-40
70-80
95-105
2,5
3,5
8
26,5
22,5
41-TII 165-185
9
5,5
41 -n
41-T
41-VI 120-130
55,9
65,8
31,9
27,7
27,0
24,5
7,7
8,2
30,0
62,5
70,3
88,4
90,5
'63,4
Exebangaabla teaaa ma/100 g
Organic n a t t a r
.lit
50-2P
C/B
12,2
6,5
10,5
5,2
3,9
1,3
6,6
8,7
9,5
9,2
8,8
8,4
8,7
6,2
Ca
2,41
0,16
0,20
2,72
0,22
0,26
0,43
0,02
0,03
1,09
23,5
23
5
4,19
0,93
6,02
4,16
14,6
0,14
0,24
20,1
17 3
14 8
12, 9
12 2
136
2.39
1,66
0,22
1,59
0,01
0,06
10
0,03
0
tr
0,01
0,01
0,02
0
8
51
66
57Ô
CaCO.
19,1
tr^
13,2
3,92
0,4è
7728" 24P?
0,22 0,03
7,0
13,4
-
18,2
1,15
2,89
0,36
22,6
22,6
15,5
13,5
-
19,7
17,8
2,03 2,53
1,76 0,27
0,72
4,31
25,0
24,1
25,0
24,1
6,8
3,8
20,9
tr
tr
tr
3,03
tr
9,51
tr
0,27
0,01
0,32
4,86
tr
3,53
3,06
7,52
O,C4
0,33
0,11
13,9
0,61
13,2
0,68
1,00
tr
0
tr
tr
67
0 , 57
38
0,
4 48
5 33
0,93
5,56
11,4
tr
0,
11,6
tr
0,
5 04
10 8
9,43
27,0
8,75
tr
0,
28,6
tr
0,
5,55
•a/100 «
0,10 0,02
13,3 0,20 0,52 4,55 18,6
6,3 2,97 0,18 2,37 11,8
16,2 3,47 0,4a 6,19 26,3
axtract ma/100 g
29,2
1,59
2,88
17,9
24,5
C.B.C.
37
23
24
22
4,59
tr
5,41
23,7
0,02
0,09
24.9
18,6
11,8
26,3
Profilai 10.
tat» of obaamtioni Pabruary 19*6.
lôatiom Chunay*.
KlaTationi 315.5 ••
Baliaft faintly «lopin«.
latiTa ragatatiom grasa.
Parant salarial! Lovar Plaiatooana proluri»l gypaun dapoaita.
Soll aurfacai fa« gjpaua polygon««) aiero-dunaa with drlad graaal lovar part« of tta» «oil aurfaca bar* aora aoiat and graan graaa.
holaa of foxaa, Bolaa and nie».
Plaid claaaifieatloni C .
Soil typai Trpio Oypaiorthid.
(a )
0 - 12 » Dry, yallowlah brovn (iO TB 5/4) » l i t , containing organic aatarial, H«11 rootad, «oft cruobly atruotur*) Margins rathar
abruptly intoi
II C 12 - 64 em dry, raddiah yallov (7.5 TB 7/6) gypaua aand, poorly rootad down to 33 o«, «lightly bard atructuralaaa, lanaas of Tartical
gypsua cryatalal lying on nard cryatalllna gypaua.
Profilai 12.
Data of obaarntlom Pabruary 1966.
Location! Cbunaya,
ElaTationt 324 ••
Bali*f1 faintly «loping.
latixa vagatatlom grasa.
Pmrant natarlali Lo«ar Plaiatoeana proluTial gypaua dapoalta.
Soil aurfacai polygonal atruoturaa of gypaunl aooa bolta aada by i n i u l i .
Plaid elaaaificationi C .
Soil typai Typio Ojrpalarthid.
(*,,)
II C1
'II C.
0 -
S OH Dry, light yallovlan brovn (iO TB 6/4) gypaifaroua s i l t , containing vary l l t t l a organic u t a r i a l , poorly rootad, aoft
pl«tj atruoturai Barging intoi
5 - 25 c i dry, vary pal* brovn (10 TB 7/4) fina tazturad gypaua a«nd, «lightly bard •tructuralaaal nrglng Intoi
2 5 - 3 0 cat dry, «hit« gypaua «*nd «isad with gypaun powdar and gypaua cryatala, baxd caoantad layar, gjpaua cry« tal a foraad »* naadlaa
or bladaa) aarging trragularly Into a layar vitb bard gypaum oryatala.
Profilai 13t»t« of obsarratiom Ntaruary 1966.
Location) Cbunaya.
Slavationi 315 a.
Raliaft soft »loping tarrain.
lativa vagatatloni graaa.
Parant amtariali Loa«r Plalatooatta proluvlal gypaua dapoalta.
Soil aurfftcai s u l l dunaa and fox bol««.
Soll condition»! »lightly aoiat to dry.
Plaid olaaaifleatlom C cr.
Soil typai Typio dypalortbld.
(A } )
0 -
II C
13 -
15 ca Slightly aoiat, light yalloviab brovn (10 TB 6/4) « i l t j loaa, aoft vaakly davalopad cruablj atruotura, 0-10 ca vail
rootad, IO-15 cm poorly rootad) aarging gradually intoi
4$ ca dry, ft? pala brovn (iO TB 6/4) grpaua povdar Bijcad vltb loaa and clay block«, allgbtly b*rd atructuralaul Barging
gradually intoi
II Cg 45 - 90 ca dry, jrallov (10 TB 7/6) fina taxturad gypaua aand aixad vitb powdar and fa« cl*y pabblaa, aottlad in tb« o lay pabblaa,
•lightljr baxd atrueturalaaai aarging Into)
II C^ 90 - 150 OB dry, light OUT« gray (5 T 6/2) clay balla tilth gypaua eryatali, iron coatings »round o lay pabblaa, bard oonalatancai
Barging abruptly intoi
II C4 130 - 160 ca dry, light ollra gray (5 T 6/2) aixtura of clay with gypaua crystal«.
Profilai 41.
Data of obaarrationi Juna 1965.
Location! Volcano region (Jabal Mankfaar Onarbi).
Bl«f»tioni 255,8 a.
Bali.ft undulating.
l a t i n T*g*tatlont abort graaa and aorghua (acattar*d).
Parant aatariali Qppar Plaiatocana to Boiocana l a p i l l i .
Soil oonditlanat «lightly aoiat to dry.
Soil eurfacai undolatlng, l a p i l l i on nafaoa.
Plaid claaalfloatlom A21L.
Soil typ. 1 typio Caabortbid.
(*.,)
0 -
(B.,)
6 -
(B2)
17 -
C,
IICj
IIC3
tIC4
54 • 92 115 150 -
6 «a Slightly aoiat to dry, pala brovn (iO TB 6/3) a*ndy loaa,( loaa with l a p i l l i ) , containing vary l i t t l a organic MAtaria.1,
vail rootad, «oft to «ligbtlj consiatanaa, tandancy to blocky atructurai Mrging gradually intoi
17 oa «lightly aolat, p*la brovn (iO TR 6/3) »andy loaa,(loaa vlth l a p i l l i ) , vail rootad, «lightly bard eonaiatanca,
tandancy to block? atruoturai aarging gradually intoi
54 ca «lightly aoiat, light yalloviah brovn (iO TB 6/4) a*ndy loan ( l a p i l l i loaa), poorly rootad, aoft oonaiatanea,
tandancy to blockj atruaturai aarglng abruptly intoi
92 oa «lightly aolat, light yalloviah brovn (iO TB 6/4) aandy lo*a,( loaay l a p i l l i ) , poorly rooted up to 72 cm, loose
atrueturalaaa; «arging Tary abruptly intoi
»15 OB dry, grey (2.5 T 5/0) l a p i l l i aand, l o o , , atruoturalaaa, aarging abruptly tntoi
150 ca dry, grey (2.5 T 5/0) »and,(fina taxturad l a p i l l i ) , Barging Intoi
165 G" «liçhtly aoiat, light yallowiah brovn (tO TB 6/4) aandy l o « , ( l a p i l l i loa») ( blocag* oa 185 «•-
137
TABLE 3 0 . 1 0 : TYPIC SALORTHIDS OP THE VOLCANO REGIOH.
Sampla
Textur« U.S.A..
sand
2n»-5On
grarel
16-1
16-11
16-11I
16-IT
0-4
2,5
20-30
60-70
145-155
7,5
36,5
17,5
55,1
44,4
47,7
14,4
pH
alit
clay
5O-2M *.2u
38 , 4
6,5
54 , 3
1,3
47 , 0
5,3
81 ,5
4,1
1?5
»,
1
8, 9
9, 0
9, 4
Organic matter
C
I
0,38 0,06
Ezcbangaabl« baaaa oe/lOO g
*
CaCO
C/H
6,3
Sus
Ca
10,4
16,3
19,8
3,0
13,5 tr 4,17 4,45
21,5 0,85 2,65 0,99
12,9 2,71 1,36 12,9
2,72 0,70 0,67 1,52
1 Q water extract me/100 g
20,1
3,81
43,1
27,1
63 , 0
4,52
64 ,3
4,52
,6
2,20
0,61
22
6 ,89
3,04
tr
19,5
23 ,2
0 , 02
20,1
22 ,3
22,7
22,5
tr
2, 04
11 , 8
11,2
tp
0,68
0,15
2 , 2 0 0 , 17 0,03
0 , 53 0 , 11 0,04
9,43
2,16
2 ,84
2,83
11 • 9
0,46
0,40
0,70
0,48
tr
tp
5,85 4,45
6 , 2 2 3,34
6 ,04 1 ,84 2,60
0 ,79 1 ,34 0,22
12
,5
Caeaical and mineraloglcal analysas of ta« olay fraction (<.2(i)t
Sample
SiO ?
nu. bar
SiO2
16 I
49,6
51,3
51,6
57,0
16 I I
16 I I I
16 IV
Clajr
Xlnarale
5,9
U,8
2•5
«o*
Chi
p
6,2
15.3
2 ,5
».*
obi
p*
I"
I»
I*
Q P
D P
2,5
6,0
»0*
Cbl
P*
I«
I*
Q P
89,0
13,3
16,9
22,8
2 ,8
1,8
1 ,7
Xo
Chi
P*
I*
IC*
Q P
310,
S10?
al
V
«=o 2
Total
ÂV 1
**2
f » 2o,
5,3
0,7
2•9
2,8
6,1
0,6
1,9
2,7
14 , 6
9,0
8 ,3
5,8
0,4
2,6
7, 3
6 ,7
3,2
3,0
11 , 0
2°3
"•2
2°3
2°3
84,6
85,8
85,8
9, 0
14 , 3
14 , 2
Pa
Al
A12O3
CaO
°3
SiO?
Total
«80
"2
0
Pa
*2 3
Chemical analyses of total s o i ! t u p i « (<.2 ma )i
Sampla
nuaber
sio 2
16 I
16 I I
16 I I I
34,5
38,3
36,2
138
"2°3
5,6
5,4
6,3
*2°3
10,2
9,5
10(2
XgO
CaO
12,4 10,7
12,0 12,3
11,6 12,0
Ha
2°
6 ,3
1,4
0,2
7,2
6 ,8
1,3
0,2
1,2
0,2
81,3
86,2
84,5
„0
10, b
9, 1
0 ,9
3
10 , 8
0 ,9
9, 9
9 ,6
12,
1,0
K*
22,1
26,0
29,9
5,61
C.E.C.
»•/IOO g
22,1
26,0
29,9
5,61
Profil»i 16.
Date of obnmtioni May 1965Location» Volcano region.
Elevation) 262,2 n.
Beliefi undulating.
Kative vsgetatiom dry grass.
Paraat materiali Upper Pleistocene to Bolocene Tolcanio lapilli mixed with loam.
Soil conditionst dry.
Soil surfacei much lapilli on surface (finir matarial bas been blown out).
Field olassificatiom A2L1 .
Soil typei Typic Salorthid.
(A t ) M
0 -
(B)
4 -
C
46 -
II C
110 -
II C_
II C
135 145 -
4 on Dry, pale brown (10 TB 6/3) sandy loan (loan; ooaree textured lapilli), poorly rooted, -nrj l i t t l e organio Material,
soft platy struoture) merging gradually intoi
48 en dry, pals brown ( 10 IB 6/3) eilt loam,(loamy coarse textured lapilli), poorly rooted, soft consistenoe, few weakly
eenented aggregate»! merging abruptly intoi
110 on dry, light yellowish brown (i0 TB 6/4) candy loam, (coarse textured lapilli with loamy adnixture), poorly rooted up
to 55 ca, soft consistence, rmxy few weakly cemented aggregates; merging abruptly intot
135 on dry, light yellowish brown (10 YH 6/4( brown due to a kind of loam coating ) or grey (2.5 Y 5/0) :©o*r«e textured
lapilli, soft oonsistsnee, atructurelese) merging abruptly intot
145 CB dry, grey (2.5 T 5/0J fins textured lapilli, soft oonsistencei merging abruptly intot
155 en extremely dry, grey (2-5 I 5/0) lapilli, soft consistence.
Profilet 46.*
Date of observation! January 1966.
Location! west of Hlsiban.
SlsTatiom 304 n.
Reliefi flat, top.
Satire vegetationt grass.
Parent naterialt recent aeolic loaa underlain by Pleistoosne gravel.
Field o l a s s i f i c a t i o n t
C2L.
Soil type 1 Typic Calciorthid.
(a_)
0
-
10
en
Dry strong brown ( 7 . 5 YB 5/8) s i l t loan, containing l i t t l e organic matter, s o f t weakly deTOloped crumbly structure,
(B)
10
-
20
cm dry strong brown s i l t loan, s o f t weakly developed crumbly structure) underlain byi
20
*
60
CB loany s k s l e t a l , rapidly norging into fragmentai ^âvel with l i n e
upper cas s o f t platy structure» merging gradually
I1C
intoi
accumulations.
°* and despar
Profilet
47.*
Date of obserrationi January 1966.
Location1 e a s t of Shininah.
Elevation1 308 a.
Belieft flat, top.
Hative vegetation! grass.
Parent material! recent aeolio loam underlain by Pleistocene gravel.
Field classification1 C3L.
Soil typet Typio Calciorthid.
(a_)
0
- 10 en Drj gravelly s i l t loan, containing l i t t l e organio natter, soft weakly developed crumbly structura, upper cms platy
structure) merging gradually intot
(B)
10
20 cm dry gravelly ailt loan, soft weakly developed cruably structure) underlain byi
20
— 60 ca gravel cemented by line.
Profile 1 6 . *
Date of obserrationi February 1?66.
Location) south of Hadi al Himar.
Elevation! 344 ••
Belief! flat, valley bottom.
Land uset barley.
Parent material! loamy valley f i l l .
Soil conditions! dry to slightly aoiet.
Field classification! Ag.
Soil typei Typie Calciorthid.
(Af)
(K)
IIC
0 - 10 en Slightly Boist s i l t loam, containing l i t t l e organio material, soft crumbly structure, the upper cms bave a platy
10 - 60 cm slightly molat (until 40 en) s i l t loam containing some gravel, subangular blockjr structure, white line spots 1
60 - 110 OB dry structureless gypsum sand)
bloeags on hard gypsun underlain by limestone.
For aoil analyses one i s reffered to tables 30.6 and 3O.7.
139
b . Clay m i n e r a l s as r e l a t e d to a v e r a g e v a l u e s of oxides in
the f r a c t i o n < 2 n.
On comparing the content of palygorskite, illite and montmorillonite with
chemical data of the fraction <2 p,, we found a direct correlation with the content
of MgO, K„O and CaO. This is indicated in table 31.
Table 31. Content of palygorskite, illite and montmorillonite as related to that
of M O, K O and CaO in the fraction < 2 p,
% Palygorskite
average
%M O
g
% illite
average
%K 2 O
0-10
10-30
30-50
1,2
4,5
8
10-30
30-50
50-75
1,9
2,4
4,0
% montmorilonite
average
%CaO
0-10
10-30
0,6
1,1
B. C l a s s i f i c a t i o n of s o i l s .
Soil development has taken place in the surface layers of nearly the whole
area.
There are only a few outcrops of bare rocks not supporting even a poor
vegetation of grasses. These outcrops are:
—the lava flows from the volcano Mankhar Gharbi; the surface is covered
by basalt blocks and aeolic loam occurs only locally to a maximum depth
of 20 cm;
—the Miocene limestone east of Hawije; the surface is covered with limestone
blocks and locally there are encrustations and/or accumulations of a few
centimeters of loam.
1. SOIL CLASSIFICATION CRITERIA
Soil classification criteria of the "Soil Classification, A comprehensive
system, 7th Approximation" and supplements (U.S. Dep. of Agric. 1960-1967)
were applied to soils of the Balikh Basin.
A subdivision of subgroups into families was made with the aid of differences in texture and mineralogy.
Not all properties given in the 7th Approximation and supplements a.o.
for calcic horizons and cambic horizons are well marked in soils of the Balikh
140
Basin and completion was necessary for highly gipsiferous soils.
Therefore, the following diagnostic characteristics were selected:
Calcic horizon—A horizon that is more than 15 cm thick, has a calcium carbonate percentage of more than 15 percent and has more than 5 percent by volume of secondary carbonate in concretions or soft powdery forms. It is found
to be identical to the (Kg) horizon.
Cambic horizon—This is a horizon which shows evidence of removal of
carbonates and consequently has less carbonates than the underlying calcic horizon. It has soil structure rather than rock structure and contains some weatherable minerals. Ithas atexture finer than loamy fine sand in the fine earth fraction and its base is at least 25 cm below the soil surface. Therefore, a cambic
horizon which is not thick enough is regarded as not diagnostic although it is
indicated as (B).
Mottling is less pronounced and this term refers in this text to spots with,
brown and strongly brown colours different from the soil matrix.
Highly gypsiferous soils are found to have a different genesis as compared with highly calcareous soils. Therefore, a new great group of Orthids was
defined and indicated as Gypsiortids having a gypsum content of more than 25
percent by weight in all parts of soil after the upper 30 cm or less are mixed.
These soils are often characterized by the occurrence of an indurated gypsic
horizon, that is a petrogypsic horizon with or without gypsum polygones.
A petrogypsic horizon contains more than 50 percent gypsum and is usually thicker than 10 cm. The induration is caused either by dehydration of gypsum and subsequent hardening after wetting, or by solution and redistribution
followed by recrystallisation of gypsum into massif plates. It is not or difficult
to penetrate by spade or auger when dry and is impermeable to roots. The hardness is 2 according to Mohs scale of hardness.
Gypsum polygones are vertical encrusted powdery or crystalline gypsum
plates.
2 . DESCRIPTION AND CLASSIFICATION OF SOILS ACCORDING TO THE 7th APPROXIMATION WITH
SUPPLEMENTS.
Soils of the Balikh Basin are characterised by the occurrence of an ochric
epipedon. The percentage of carbon in the upper 10 cm is often higher than
0,58 percent but drops rapidly below this depth to 0, 30 percent or less. The
upper 4 cm are generally crusty. The soils are classified as Entisols and Aridi141
sols.
For complete definitions of orders, suborders, great groups and subgroups
one is referred to the "Soil Classification, A comprehensive system, 7th Approximation" and supplements. Only properties of the soil profile regarded as
most characteristic in the region are given below.
a. E n t i s o l s of t h e B a l i k h
Basin.
Mineral soils that have no diagnostic horizon other than an ochric epipedon.
a.l. F l u v e n t s .
Entisols that
1. have textures of loamy very fine sand or finer;
2. have an organic matter content that decreases irregularly with depth
or remains above 0, 35 percent (0, 2 percent carbon). Thin strata of
sand may have less organic matter if the finer sediments at 1, 25 m or
below have 0, 35 percent or more;
3. are not permanently saturated with water;
4. have a mean annual soil temperature of more than 0°C.
a.l. 1. T o r r i f l u v e n t s .
Fluvents that
1. have a mean annual soil temperature of more than 8 C and a mean
summer soil temperature at a depth of 50 cm of more than 15°C
(chapter I, B,3);
2. are usually dry in most years in all parts of the soil between 18 and
50 cm.
a.1.1.1. T y p i c T o r r i f l u v e n t s
(table 30.1: profiles 20 and 52).
Torrifluvents that are not Vertic or Durorthidic.
The greater part of soils lying on the Euphrates lowest terrace belongs
to this subgroup. The soils are classified into three families according to differences in texture. These are loamy, clayey and loamy over sandy.
Salinity is generally low, but strongly saline soils due to irrigation activity are found locally e.g. profile 52. This profile is classified as aTypicTorrifluvent (loamy) and has an EC inthetopsoil of 26,0. Comparison of the composition of cations and anions in the 1:5 water extract reveals the occurrence of
142
NaCl and CaSO4<
Locally at the foot of the terrace escarpments, salts were accumulated by
drainage water, resulting in a weakly to moderately saline soil.
The soil profile nr. 20 was classified as a Typic Torrifluvent (loamy). The
mineralogical assemblage of this profile is fairly uniform despite the sedimentary variation in grain size. This is shown also by the silica/alumina ratios of
the total soil sample, which are only slightly lower in samples 20 II and IV with
a low content of sand. Quartz, chalcedony, acid plagioclase andmuscovitearethe
dominant minerals of sand and coarse silt fraction while montmorillonite is the
most abundant mineral of the clay fraction. Easy weatherable minerals are still
present.
Opaline silica occurred in a relatively high percentage of the sand fraction
showing a certain degree of mobility of silica in being taken up by plants.
There is only a weakly developed structure while the sedimentary platy
fabric is still present. Some mottling occurs in subsoil and deeper subsoil,
but there is no significant iron illuviation.
Chemical reaction is alkaline with a pH of 8,4. The adsorption complex is
highly saturated with calcium and magnesium as dominant cations.
The organic matter content is low and decreases irregularly with depth.
The C/N ratio is narrow, the organic matter being in a well mineralized condition. The percentage of carbon depends on texture. A silty clay at a depth of
185 cm was found to have 0, 33 % carbon while a sandy loam at a depth of 75 cm
had only 0, 05 % carbon. However, generally the content of carbon remains above
0,2 percent.
EC and E . S . P . values of profile 20 are small and salts or alkali do not
effect plant growth.
Leaching of silica and alumina is nil, the silica/alumina ratio slightly increases upwards in the soil profile.
Comparison of the chemical data from the fraction <2 p, with those of Typic
Calciorthids shows a higher content of CaO (Mo ) and a smaller percentage of
K 2 O(I + ).
Some sodium accumulated in the subsoil, but there is a general trend of
accumulation of sodium and potassium in the topsoil owing to an upwards movement of easy soluble ions with the evaporating water. Most of these ions have
been derived from the salt containing irrigation water.
The silica/alumina ratios are high due to the high content of montmorillonite
and the contribution of palygorskite.
143
a.1.2. U s t i f l u v e n t s .
Fluvents that
1. have a mean annual soil temperature of more than 8°C and a mean summer soil temperature at a depth of 50 cm of more than 15 C ( chapter
I, B,3);
2. are usually moist but are dry for 90 cumulative days or more inmost
years in some subhorizon between 18 and 50 cm but are not continuously dry in all subhorizons between these depths for as long as 60 consecutive days in more than 7 out of 10 years.
a.1.2.1. T y p i c Us tif l u v e n t s (table 30. 2: profile 7).
Ustifluvents that lack the properties as defined for the Vertic Ustifluvents described in a. 1.2.2.
These soils are found in the Balikh and Euphrates valley e.g. the flood
plains of Nahr Balikh and Wadi al Kheder, and north of Hazimah at the confluence
of former and recent course of the Balikh.
The soils are classified into 2 families according to differences in texture.
These are loamy and clayey.
Loamy soils are found where the Balikh takes its course through the Holocene Euphrates terrace.
The greater part of soils have a clayey texture, are mottled, highly calcareous and the adsorption complex is highly saturated with calcium and magnesium (see profile 7).
a.1.2.2. V e r t i c U s t i f l u v e n t s
(table 30.3: profiles 15, 19, 27 and 51).
Ustifluvents that differ from the Typic in having
a. cracks at some period inmost years that are 1 cm wide at a depth of 50 cm,
that are at least 30 cm long in some part, and that extend upward to the surface or to the base of an (A^ horizon;
b. more than 35 percent of clay in horizons that total more than 50 cm in thickness within the control section.
Some other characteristics found in these soils are;
— Gilgai is absent or very weakly developed;
— the content of swelling clays is only 5-10 percent of total soil;
— slickensides are small and merely stress faces, and intersecting slickensides are not observed;
144
— parallelepiped structural aggregates are small and weakly developed.
The soils have a fine clayey texture and an ochric epipedon.
Soil structure is weakly developed while a sedimentary platy fabric is still
present. It has a low stability and is destructedby thoroughly wetting. Only in
profile 27 being relatively dry for some period has a pronounced soil structure
developed.
The minéralogie assemblage is fairly uniform although sedimentary variations occur, niite, palygorskite, quartz, albite and orthoclase are the dominant
minerals. The minéralogie al and chemical composition of the fine silt fraction
5-10 p, does not differ very much from that of the clay fraction < 2 p,, only chlorite is more abundant in the fine silt fraction.
The topsoil has a higher content of illite and a lower content of palygorskite as compared with the underlying layers..
The silica/alumina ratios of the clay fractions are about 5,5. The ratio of
the upper topsoil is slightly lower than that of the underlying horizons and indicates a slight leaching of silica.
The adsoiption complex is highly saturated and the dominant cations are
calcium and magnesium. The high magnesium content of Balikh soils will be due to
.weathering of marl in the upper course of the Balikh.
EC e and ESP values are low and the lime content is about 25 percent.
Powdery lime accumulations are weakly developed or absent.
The occurrence of cracks filled with clay and organic matter together with
stress faces in subsoil and deeper subsoil are regarded as highly characteristic.
The latter are due to the swelling and shrinking of montmorillonite as a result
of marked changes in moisture content.
The profiles are characterized by zones with prominent mottling. The occurrence of several levels with intensive mottling in profile 19 indicates intermittent moistening.
Cracks were observed up to a depth of 100 cm and are several centimeters
wide.
The organic matter in the cracks being protected against strong insolation
is not destroyed and has a black colour.
145
a.2. O r t h e n t s .
Entisols that
1. have textures of loamy very fine sand or finer;
2. have an organic matter content that decreases regularly with depth;
3. are not permanently saturated with water.
a.2.1. T o r r i o r t h e n t s .
Orthents that
1. have a mean annual soil temperature of more than 8°C (chapter I B,3);
2. are usually dry in most years.
a.2.1.1. L i t h i c
Torriorthents..
Loamy soils overlying limestone within 30 cm of the surface are placed
in this subgroup. No diagnostic horizons other than an ochric epipedon developed
in the loam.
These soils are found in places where a thin loamy cover is present on
nd
limestone outcrops in the if Balikh terrace.
a.3.
Psamments.
Entisols that
1. have below the (A ) horizon or 25 cm, textures of loamy fine sand or
coarser in all parts to a depth of 1 m ;
2. are not permanently saturated with water.
a.3.1. To r r i p s a m m e n t s .
Psamments that
1. have a mean annual soil temperature of more than 8°C and a mean
summer soil temperature of more than 15°C ;
2. are usually dry in most years in all parts of the soil between 18 cm
and 50 cm;
3. have in the sand fraction, less than 95 percent quartz, zircon, tourmaline, rutile or other normally insoluable minerals that do not
weather to liberate iron or alumina.
a.3.1.1. Typic T o r r i p s a m m e n t s .
These soils are found locally on the Euphrates lowest terrace and in
some isolated patches of the Volcano area.
146
The Typic Torripsamments of the Euphrates area have a sandy texture up
to lm.
Those of the Volcano area are built up of coarse-textured lapilli without
an admixture of loam or they are found in places where only the upper 25 cm
or less are mixed.
a.3.2. U s t i p s a m m e n t s .
Psamments that
1. have a mean annual soil temperature of more than 8 C and a mean
summer soil temperature at 50 cm of more than 15°C ;
2. are usually moist but are dry for 90 cumulative days or more in most
years in some subhorizon between 18 and 50 cm but are not continuously dry in all subhorizons between these depths for as long as 60 consecutive days in more than 7 out of 10 years;
3. have in the sand fraction less than 95 percent quartz, zircon, tourmaline, rutile or other normally insoluable minerals that do not
weather to liberate iron or aluminium.
a.3.2.1. T y p i c
Ustipsamments.
Soils of the Euphrates flood plain which are sandy up to 1 m are placed
in this subgroup.
b. A r i d i s o l s of t h e B a l i k h
Basin.
b.l. O r t h i d s .
Aridisols that
1. have within 1 m of the surface one or more of the following horizons:
calcic, gypsic, petrogypsic or cambic;
2. are usually dry between 18 and 50 cm depth or have a conductivity of
the saturation extract that is 2 mmho per cm or greater at 25 C in some
part above 125 cm if particle size class is sandy, 90 cm if loamy and
75 cm if clayey;
3. have a salic horizon with its upper boundary within 75 cm of the surface
and are saturated with water within lm of the surface for one month
or more.
147
b.1.1. C a l c i o r t h i d s .
Orthids that
1. have either a calcic or gypsic horizon that has its upper boundary
within 1 m of the surface;
2. are calcareous in all parts above the calcic horizon after the upper
18 cm are mixed unless textures are coarser than loamy very fine
sand;
3. have no petrogypsic horizon within 60 cm of the surface;
4. have no salic horizon above the calcic or gypsic horizon.
b.1.1.1. Typic
Calciorthids.
Calciorthids that
a. have dominant chromas of 4 ore more;
b. have a weighted average carbon content in the surface 38 cm of
less than 0,58 percent if the weighted average sand/clay ratio for
this depth is 1, 0 or less; or 0,16 percent if the ratio is 13 or more;
or intermediate ratios have intermediate carbon contents;
c. are usually dry between depths of 18 and 50 cm.
Six different families were recognized being loamy or clayey, loamy over
fragmental, loamy over sandy gypsum, loamy over marl, marly and loamy
lapilli,
a. Typic Calciorthids; loamy or clayey (table 30.4 and 30.5).
These soils are characterized by the occurrence of a calcic horizon locally
underlain by a gypsic horizon. They developed in the loamy cover of the Pleistocene terraces and in the loams and clays of the Balikh alluvial.
The loamy soils covering the Pleistocene terraces will be discussed first
(table 30.4: profiles 5, 24, 31, 18, 26, 32, 38, and 42).
The minéralogie assemblage
is f airly uniform ; quartz, chalcedony, al-
bite, orthoclase, illite and palygorskite are the dominant minerals. The content
of montmorillonite was found to be slightly higher in the topsoil as compared
with the underlying soil.
A thin platy surface crust is underlain by a succession of the following
structural horizons which gradually merge into each other:
a horizon with crumbly structure;
a horizon with subangular blocky structure ;
a horizon with blocky structure.
148
The platy surface crust is usually cracked (distance from one crack to another 7. 5-12, 5 cm) and has a low clay content.
A calcic horizon was found at different depths but generally between 40 cm
and 70-100 cm. The secondary lime accumulated as white powdery fillings,
concretions, pseudomycelia, pendants or crusts below pebbles and stones, and
as thin sheets at the transition of loam into lapilli.
The average percentage of calcium carbonate of the different soil horizons
is as follows: (A) 20,0%, (B)22,0%, (1^)23,5%, (K„) 28, 5 and (Kg> 27,4 %.
A gypsic horizon was found locally in the deeper subsoil (profile 42) or
below a depth of 1 m (profiles 24, 8 and 38). Secondary gypsum accumulated as
transparent crystals uniformly in the loamy material or as pendants under gravel and stones.
A cambic horizon is situated above the calcic horizon and has fewer carbonates, the average difference between the two horizons being 6, 5 percent. The
ochric epipedon contains on an average 8,5 percent carbonates less than the
calcic horizon. A summary of properties is given in fig. 21.
soil horizon
designations
depth
crunibl)
subangular
blockv
lime controlion!
diagnostic
horizons
< 2%
ochric
epipedon
cambic
horizon
(••y v o l Lime
2-5 %
by volume
blocky
2M,
bv volume
5
calcic
horizon
3-5 %
by volume
naie: The average permeability in k. 10-4 cm/secflstaelsen and Hansen, 1 !»62)
Fig. 21. Summary of properties of Typic Calcionhids
Although the aggregate stability is low, permeability appears to be related
directly to soil structure.
The very thin surface crust has a low permeability (D.S. Mclntyre, 1958).
149
The influence of the surface crust on soil permeability is illustrated by
the lower permeability of the upper 10 cm which can only be due to the presence
of this crust since the underlying layer has a good permeable crumbly structure.
Below the crumbly topsoil permeability is decreasing owing to a subangular
blocky structure merging into a blocky structure with low permeability.
Fig. 22. A Typic Calciorthid.
150
In the clay fraction, the silica/alumina ratios are relatively high and vary
between 4 and 6,7. The Si O_/A1 O and Al O /Fe o O_ ratios are given in fig. 23.
Generally there is an increase of silica in the upper topsoil and deeper
subsoil, while the lower topsoil and subsoil show a slight leaching of it.
Profile 31 shows a relatively high increase of silica in the clay fraction
of the deeper subsoil owing to a contribution of amorphous silica derived from
volcanic glass.
The SiO /Al O ratio of the total soil is only slightly higher than that of
the clay fraction indicating a high content of clay minerals in the fine silt fraction which is an important quantity of soil.
AI 2 0 3 /Fe 2 0 3
SiO2 / AI 2 o 3
1
J
i
S
*
T
/
/
fo
cms.
I S
4
I
v:{
40
\
io
.n
o.
•o
fÛA
toe
Soil
Profile 5
profiles
Profile 24
Profile 37
Profile 31
Fig. 23. SiO /Al O and Al O /Fe O ratios of the clay fraction of Typic Calciorthids ( loamy )
The adsorption complex is highly saturated and the dominant cation is
calcium.
The EC e and E . S . P . are generally low and the percentage of calcium carbonate varies between 15 and 30 percent.
Salts accumulated in subsoil and deeper subsoil in some flat depressions
and valleys (profiles 18, 24, 31, 38 and 42). These soils are only weakly saline and the effect of salts on plant growth will not be great.
A moderate content of salt is met with occasionally in the lower part of
soil (profiles 18 and 38).
151
Typic Calciorthids; loamy or clayey of the Balikh valley (table 30.5: profiles 37,8 and 34) differ from the Typic Calciorthids found on the Pleistocene
terrace by the following properties:
— texture is more heavy being silt loam over clay or clay loam;
— the calcic horizon is less developed;
— the crumbly structure of the topsoil is less developed;
— the content of MgO of total soil and exchangeable magnesium are relatively
high;
— locally there is a very high percentage of calcium carbonate (profile 8).
b. T y p i c C a l c i o r t h i d s ; l o a m y o v e r f r a g m e n t a l (Table 30.6: profiles 29,44-47).
The shallow loam soils overlying gravel were placed in this subgroup.
The covering loam has a thickness of less than 30 cm. The soils have an ochric
epipedon and a calcic horizon is more or less developed in the gravel. In some
places a gypsic horizon developed e.g. profile 44. These soils are found on
outcrops of the Pleistocene gravel where the covering loam is thin and the terrain is moderately to highly accidented.
The soil material is highly calcareous and consequently calcium is the
dominant cation of the adsorption complex. The chemical reaction is alkaline
having a pH of 8,2.
The development of a calcic and/or gypsic horizon in the gravel is dependent on the degree of accumulation and erosion of calcareous or gypsiferous
loam. Erosion retards the development of these horizons while accumulation
stimulates their development. Some leaching after wetting of the loamy surface
layer during rainy periods will'lead to accumulation of lime and/or gypsum in
the underlying gravel.
No diagnostic horizons other than an ochric epipedon developed
in the loamy top layer, this being rapidly removed owing to the high erosion
forces acting in the accidented terrain in which these soils are found.
A classification of these soils as Lithic Calciorthids, having a lithic contact within 50 cm of the surface, would be more justified for practical reasons.
However, the gravel being not coherent material cannot be classified as
a lithic contact although it is not possible to penetrate with spade or auger but
only with a pick-axe. Therefore, it is suggested to use the name Psephitic Cal152
ciorthids for such soils.
c. T y p i c C a l c i o r t h i d s ; l o a m y o v e r s a n d y g y p s u m (table 30.7:
profiles 6, 17, 39, 40 and 43).
The calcareous loamy top layers generally have the same soil properties
as described for the Typic Calciorthids developed in the loamy cover over the
Pleistocene terraces.
However, the low situation in the terrain and being generally surrounded
by gypsiferous outcrops together with the lower layers of highly gypsiferous
material have a marked influence on soil properties.
Therefore, in addition to the properties of the Typic Calciorthids which
are more or less well developed, these soils are characterized by:
— a generally weakly to moderately saline subsoil and deeper subsoil (profiles 17, 39 and 40);
— development of gypsic horizons characterized by gypsum crystals in loam
or cemented horizons in gypsum sand;
— mottling in subsoil and or deeper subsoil;
— highly gypsiferous soil layers which are stuctureless and have a low content of silica and alumina because of their low clay percentage.
A very high percentage of calcium carbonate was met with in profile 6 which
is situated in a valley surrounded by limestones.
d. T y p i c C a l c i o r t h i d s ; l o a m y o v e r
marl.
These soils are found in the northern part of the region where marl lies
near the surface. A calcic horizon developed in the loam covering marl.
e. T y p i c C a l c i o r t h i d s ; m a r l y .
These soils are found in the northern part of the region. They have the
following characteristics:
A white (10 YK. 8/2) calcareous clay with a granular structure, and lime mycelia
at a depth between 20 cm and 100 cm,
The organic matter content of the topsoil is low and a calcic horizon is
more or less developed.
153
f. T y p i c C a l c i o r t h i d s ; l o a m y l a p i l l i .
The loamy lapilli at the transition to the loam covering terrace often have
below the ochric epipedon a cambic horizon underlain by a gypsic horizon and
therefore were classified as Typic Calciorthids.
b.1.2. G y p s i o r t h i d s .
Orthids that
1. have a gypsic and/or petrogypsic horizon with or without gypsum
polygones which has its upper boundary within 60 cm of the surface;
2. have a gypsum content of more than 25 percent in all parts of soil
after the upper 30 cm or less are mixed.
b.1.2.1. T y p i c G y p s i o r t h i d s (table 30.8: profiles 30, 10, 12 and 13).
Gypsiorthids that
a. have dominant chromas of 4 or more;
b. have a weighted average carbon content in the surface 38 cm like
the Typic Calciorthids (b. 1.1.1.);
c. are usually dry between a depth of 18 cm and 50 cm.
Although gypsum sand has a deficiency in plant nutrients, is non-plastic
and structureless, it inust be regarded as soil because it is able to support some
kind of vegetation.
Generally it has some admixture of more favourable soil material.
The petrogypsic horizon cannot be regarded as a lithic or paralithic contact, the underlying material being not coherent or not partially consolidated.
Whereas a petrocalcic horizon is the result of soil formation over a long
continuous period, a petrogypsic horizon may be a rather recent formation.
Therefore, the Gypsiorthids are not paleosols and cannot be classified as
Paleorthids.
The soil profile is characterized by three different layers (fig. 24):
(a) aeolic calcareous silt or silt loam, underlain by
(b) aeolic gypsum sand without small clay blocks or clay pebbles, underlain by
(c) proluvial gypsum sand with small brown or grey clay blocks and pebbles, or
small greenish-grey marl blocks.
The aeolic silty top layer has a minéralogie assemblage indentical to that
of the Terrace-Balikh province (see chapter III, A, 5). Locally a beginning of
154
Fig. 2 4 . Typic Gypsiorthid. AeoLic silt loam is underlain by aeolic gypsum sand lying over clay
mixed with gypsum.
a calcic horizon was found in the thin loam cover.
The gypsum deposits are composed for more than 30 percent of gypsum.
The aeolic gypsum has an admixture of material which resembles that of
the Terrace-Balikh province.
The mineralogical composition of the clay fraction of the gypsum deposits
differs from that of the covering loam in having a higher content of palygorskite, and montmorillonite Is often lacking.
The clay blocks of the proluvial gypsum are found to have a minéralogie
155
composition rather similar to that of Miocene or Pliocene clay with palvgorskite
and illite.or chlorite as dominant clay minerals. The C.E.C. and exchangeable
magnesium and calcium are becoming higher downwards in the soil profile with
increasing admixture of clay e. g. in profile 13.
The sandy gypsiferous material has a low content of silica and alumina.
The average content of silica of total gypsum soil (profile 30) is 14 percent.
The soil solution is saturated with gypsum. The main soluble salts found
in the 1:5 water extract are calcium sulphate, magnesium sulphate and some
sodium chloride (profile 30). Low amounts of calcium and magnesium chloride
occur in samples 10 II and 13 I. The gypsum content varies between 47, &",. and
74,9%.
The aeolic silty top layer generally has an admixture of gypsum which can
be as high as 37, 5%. The morphology of this silty layer is similar to that of the
topsoil of Typic Calciorthids (loamy).
The gypsum sand is structureless. A petrogypsic horizon or gypsumcrust
is formed near the surface owing to dehydration of gypsum at temperatures
higher than 38 C followed by solution and subsequent hardening after periods
with rainfall.
Gypsum being moderately soluble (2,6 grams per liter) is easily redistributed within the soil profile. The following gypsum accumulations due to solution and redistribution were observed:
— fine crystalline gypsum cementing gypsum sand (profile 30);
— moderate to coarse gypsum crystals where an underlying horizon has a low
permeability e.g. above horizons with clay balls (profile 13);
— filling of cracks in the gypsum crust (polygones);
— recrystallisation of powdery gypsum crust and polygones into transparent
crystalline gypsum plates;
— pockets with coarse or fine crystalline gypsum in calcareous loam;
— pendants at the bottomside of gravel and pebbles;
— crystallised gypsum in root remnants.
Gypsum polygones (fig. 25) preserved rather well owing to their vertical
orientation.
They are characterized by:
— a laminary structure;
— a tendency to a hexagonal structure; angles measured between polygonal
plates vary between 110 and 130 ; with increasing age several plates dissappear and the pattern becomes more chaotic;
156
Fig. 25. Massive cr^'stalline gypsum polygones.
— the original powdery polygones can be converted after considerable time
into massive crystalline gypsum plates;
— sabakh phenomena which are often found where polygonal structures developed.
Fan-like oriented gypsum plates were observed in Miocene gypsum deposits but occur also at the surface of gypsiferous soils.
Crystalline gypsum lying at the surface shows small solution pits, and
cracking owing to alternating high and low temperatures.
A powdery gypsumcrust is present in profile 13 between a depth of 15 cm
and 45 cm while the profiles 10 and 12 have at a depth of 50-60 cm a layer of
massive crystalline gypsum which in the latter profile is underlain by sandy
gypsum.
Lenticular hollows partly filled with vertical oriented gypsum needles developed near the soil surface in profile 10.
157
Fig. 26. Typic Cypsiorthid ( profile 10 ) with vertical oriented gypsum needles.
b.1.3.
Camborthids.
Orthids that
1. have a cambic horizon;
2. have no calcic, gypsic or petrogypsic horizon that has its upper boundary within 1 m;
3. have no salic horizon with its upper boundary within 75 cm of the surface if saturated with water (i.e. within the capillary fringe) within
1 m of the surface for 1 month or more.
b. 1.3.1. T y p i c C a m b o r t h i d s .
(table 30. 9: profile 41).
Camborthids that
a. have a weighted average carbon content in the surface 38 cm of
less than 0, 58 percent if the weighted average sand/clay ratio for
this depth is 1, 0 or less; or 0,16 percent if the ratio is 18 or more;
153
or intermediate ratios have proportional carbon contents;
b. are usually dry in all parts of soil between depths of 18 and 50 cm.
These soils are found in the lapilli region and have a sandy loam texture.
The upper 60 cm are intensively mixed with loamy material of the same
mineralogical composition as the Terrace-Balikh province (chapter HI).
The lapilli is composed mainly of olivine, volcanic glass, augite and nepheline.
Fig. 2r. Typic Camborthid developed in loamy lapilli.
159
Profile 41 has a low percentage of carbon in the upper 6 cm due to accumulation of material poor in organic matter. The underlying 11 cm have a higher content of organic matter. This profile has an admixture of loam up to 92
cm, is underlain by pure lapilli up to 150 cm and below this depth the lapilli is
again mixed with loam. Apparently deposition of lapilli has found place simultaneously with that of loam.
In order to evaluate the influence of the basaltic lapilli on soil properties
the chemical data were compared with those of the Typic Calciorthids developed
in material of the Terrace-Balikh province. The chemical properties of the
lapilli soils are markedly different. The deviating properties are given below
(chemical analyses of profile 16, table 30.10, are also used):
— although the chemical composition of the clay fraction of loamy lapilli soils
is nearly identical, the content of silica is somewhat higher due to the
high amount of amorphous silica derived from the lapilli;
— the percentage of M O and Na O is higher in the lapilli (16 TV) owing to the
g
&.
presence of olivine, nepheline and volcanic glass;
—.thelapillihaveahighercontent of sand and grains>2 mm but a lower content
of clay;
— structure in lapilli soils is only weakly developed and shows, depending on
the content of calcareous loam, only a tendency to blocky structure;
— the pH of the topsoil is about 8. 7-8, 9 which is similar to that of the brown
loam, but it is higher in lapilli rich material being 9, 0-9,4;
— the percentage of carbon and nitrogen is lower;
— the calcium carbonate content is lower;
— the EC and E.S.P. are extremely high due to the sodium content derived
from easy soluable volcanic glass and nepheline;
— the composition of anions from the 1:5 water extract of soil is characterized by a higher content of chloride ions (profile 16 has a relatively high
content of nitrate ions too) ; often salts accumulated at different depths
and sabakh was observed at many places e.g. north-east of the Volcano.
The chemical composition of the parent material and weathering under arid
conditions have largely prohibited soil formation.
The high percentage of sodium and easy soluble salts were not favourable
for plant growth, with the result that the organic matter content remained low
and a crumbly structured topsoil did not form. In addition soil erosion by wind
action is intensive due to the sandy texture and scarcity of vegetation.
160
b.1.4. S a l o r t h i d s .
Orthids that
1. have a salie horizon with its upper boundary within 75 cm of the surface if saturated with water (i.e. within the capillary fringe) within
1 m of the surface for 1 month or more ;
2. have no calcic or gypsic horizon above the salic horizon.
b.1.4.1. T y p i c S a l o r t h i d s (table 30.10: profiles 16).
Salorthids that have a weighted average carbon content in the surface
38 cm like that of the Typic Calciorthids (b. 1.1.1.).
These soils contain lapilli and are found only locally in the Volcano region
in low situated terrain. A salic horizon formed in the upper 48 cm of profile 16.
The EC of 63 mmho corresponds to an approximate salt content of 2,6 percent.
6
Sodium chloride is the main component of the 1:5 soil/water extract, but sodium
nitrate, sodium sulphate and gypsum occur in lower amounts and there is a subordinate content of calcium bicarbonate.
,3. A COMPARISON WITH OTHER SOIL CLASSIFICATION SYSTEMS
The various synonyms for these soils found in the literature e.g. Dewan
(1959) and the "Soil map of the Near East (1963), Dudal (1968) are given below.
Fluvents and Typic Ustipsamments are equivalent to Eutric Fluvisols or
alluvial soils.
Lithic Torriorthents and Typic Torripsamments can be classified as
Rhegosols.
Typic Calciorthids are approximately equivalent to Sierozems, Calcic
Xerosols, Calcareous soils, Yellow soils (Strebel 1965), Cinnamonic soils
(v. Liere), Arid brown soils (Jenny 1941) or Brown subdesertic soils (Kovda
and Lobova 1961).
Typic Gypsiorthids are referred to as Gypsic Xerosols, Sierozems, Desert
soils and Gypsiferous soils. Dewan (1959) classified these soils as Rhegosols
on gypsum and for being mostly saline as an intergrade between Rhegosols and
Solonchaks.
Typic Camborthids are referred to as Calcic Cambosols or Sierozems.
Typic Salorthids are equivalent to Ochric Solonchaks, Halomorphic soils
or White alkali soils.
161
Most of the Camborthids and Salorthids developed in lapilli-loam have an
exchangeable sodium percentage of more than 15 percent and therefore can be
classified as Alkali soils.
This comparison does not mean that the various soil names used by different authors for soil types comparable with those in the Balikh Basin indicate
soil types which are similar or identical, there maybe some deviation in
properties between them.
4. THE SOIL MAP
A soil map with a scale 1:50.000 was compiled as the result of aerial
photo interpretation, field observations, evaluation of soil analyses and subsequent classification of soils according to the "Soil Classification, A comprehensive system, 7th Approximation" (1960) with supplements (1964, 1967).
This map is given in appendix HI and IV. Its legend corresponds to the division given in section B, 2 of this chapter. For mapping methods one is referred to chapter VII.
There is a striking resemblance between the soil map and the morphological map ( fig. 9). The Azonal Entisols are found in the alluvial plains of Balikh
and Euphrates while zonal Aridisols occur on the older plateau lands and the I
terrace of the Balikh. The area with Gypsiorthids largely coincides with the
Gypsum region, that of Calciorthids with the Terrace region and the lowest terrace of the Balikh, and Camborthids occur in the Volcano area.
In order to show the spatial difference of soil genetic horizons along topographical forms, geo-pedological profiles were constructed. These are given
in appendix II.
A calcic horizon developed if enough calcareous material was present for
a continuous long period or when there was a regular supply of this material
followed by leaching of carbonates. A repetition of calcic horizons was present
in lower situated places on the Pleistocene terraces where several meters of
loam accumulated (app. n, profile AA1).
A gypsic horizon was found in calcareous loam in places where gypsum
precipitated from drainage water coming from adjacent high terrains with gypsiferous outcrops. A gypsum crust (petrogypsic horizon) occurs where practically pure gypsum lies at the soil surface or at greater depth when buried un-
162
der loamy deposits (app. II).
C. M o r p h o l o g y and mic r o m o r p h o l o g y of A r i d i s o l s of t h e
Balikh
Basin.
Thin sections (see Vul, A, 1) of Aridisols were studied with the aid of a
microscope and structure photograms (2 x and 10 x enlargement).
The quantimet method applied by Jongerius of the Dutch Soil Survey Institute (Wageningen, The Netherlands; publication in preparation Geoderma) has
been proved to be an adequate means for evaluation of porosity and degree and
type of aggregation. The quantimet apparatus supplies several figures e.g. the
surface porosity (A) in percentages and the perimeter of aggregates (P) expressed in projection units (P-units) ; a high P-value indicates a high degree of aggregation.
The general methods for morphological description are given in the "Soil
survey manual" (1951) and by Jongerius (1957).
The micromorphological description was done after Brewer (1964) although
in some cases completion was necessary.
The indications used are defined below.
— Skeleton grains of a soil material are individual grains which are relatively stable and not readily translocated, concentrated or reorganized by soil
forming processes.
— Plasma of a soil material is that part which is capable of being or has been
moved, reorganized and/or concentrated by the processes of soil formation.
— Plasma concentrations are concentrations of any of the fractions of the plasma in various parts of the soil material due to soil formation.
— Plasma separations: features characterized by a significant change in the
arrangement of the constituents rather than a change in concentration of
some fraction of the plasma.
— Soil structure : the physical constitution of a soil material as expressed by
the size, shape and arrangement of the solid particles and voids.
— Soil fabric: the physical constitution of a soil material as expressed by the
spatial arrangement of the solid particles and associated voids.
— A ped is an individual natural soil aggregate consisting of a cluster of primary particles, and separated from adjoining peds by surfaces of weakness
which are recognizable as natural voids or by the occurrence of cutans.
— Pedality: the physical constitution of a soil material as expressed by the
163
size, shape and arrangement of peds.
— Pedality symbol: this has the following features,
1st. grade of structure or cohesion of peds (Soil survey manual) ;
0. structureless, 1. weak, 2. moderate, 3. strong;
2nd. accomodation (arrangement of peds) ; A . unaccomodated, A . partly
accomodated, A
. accomodated;
3rd. re-entrant angles (conformation of peds); R . weakly re-entrant (less
than 1/3 of interfacial angles), R
of interfaciel angles), R
. moderately re-entrant (1/3-2/3
. strongly re-entrant (more than 2/3 of
interfacial angles) ;
4th. surface of peds (shape of faces); S°. plane, S + . smooth, S ++ . curved.
— Voids: these are interconnected in any material which consists of packing
of individuals; soil materials can be regarded as having a single void of
intricate shape which varies considerably in its dimensions ;
-packing voids are due to random packing of individuals;
-vughs are relatively large voids, other than packing voids, usually irregular;
-vesicles have smooth, simple-curved walls, which are smooth and regular;
-channels are very large voids with a generally cylindrical shape, smoothed
walls and regular conformation;
-planes are planar voids.
— Soil matrix: this is the material within the simplest peds, it consists of the
plasma, skeleton grains and voids that do not occur in pedological features
other than plasma separations.
— Plasmic fabric: the feature of the plasöia which deals with arrangement of
the material within the simplest peds.
1. Asepic plasmic fabrics: these fabrics have dominantly anisotropic plasma with a flecked extinction pattern and no plasma separations.
-Calciasepic fabric: the plasma of this fabric exhibits a flecked orientation and has an important proportion of carbonates e.g. 15-40 percent being of definite importance for the physical constitution of the
soil material.
-Argillasepic fabric : the plasma of this fabric consists dominantly of
anisotropic clay minerals and exhibits a flecked orientation pattern
with recognizable domains which have some degree of preferred orientation.
2. Sepic plasmic fabrics: these fabrics have recognizable anisotropic do164
mains with various patterns of preferred orientation; that is plasma
separations with a striated extinction pattern (a linear or curved linear
arrangement of the plasma aggregates) are present.
-Skelsepic fabric : part of the plasma has a flecked orientation pattern,
but plasma separations with striated orientation occur subcutanically
to the surface of skeleton grains.
3. Crystic plasmic fabrics: the plasma is usually anisotropic and consists
of recognizable crystals of the more soluble plasma fractions, being
soluble in water e.g. gypsum and halite.
-Allotriomorphic crystic fabric: the plasma is characterized by anhedral
crystals.
— Pedological features : recognizable units within a soil material which are
distinguishable from the enclosing material.
— Cutan: concentration of particular soil constituents or in situ modification
of the plasma at natural surfaces in soil materials such as channels, peds
and skeleton grains.
— Grain cutans: cutans associated with the surfaces of skeleton grains or
other discrete units, such as nodules, concretions etc.
— Cutans are classified a.o. according to the mineralogical nature of the
cutanic material: argillans (clay minerals); sesquans (sesquioxides or hydroxides); soluans (carbonates, sulfates and chlorides of calcium, magnesium and sodium) e.g. gypsans (gypsum) and calcitans (calcite).
— Pedotubule: a pedological feature consisting of soil material and having a
tubular external form with sharp boundaries.
— Aggrotubules : pedotubules composed of skeleton grains and plasma which
occur essentially as recognizable aggregates within which there is no
directional arrangement with regard to the external form.
— Isotubules : pedotubules composed of skeleton grains and plasma that are
not organized into recognizable aggregates and within which the basic fabric
shows no directional arrangement with regard to the external form; the
basic fabric is essentially porphyroskelic.
— Striotubules differ from isotubules in having a basic fabric with a directional arrangement related to the external form.
— Mull or clay-humus accumulations: biogenical mixed complexes of clay and
very fine grained strongly humified organic matter.
— Glaebules are three dimensional units within the soil matrix and are usually approximate prolate to equant in shape. Their morphology is incom165
patible with their present occurence.
— Nodules are glaebules with an undifferentiated fabric, that is, there is no
specific orientation pattern with regard to the shape of the glaebule.
— Concretions: glaebules with a generally concentric fabric about a center
which may be a point, a line or a plane.
— Intercalary crystals: crystallaria that consist of single large crystals or
groups of a few large crystals set in the soil material and apparently not
associated with voids of equivalent size or shape.
1. TYPIC CALCIORTHIDS; LOAM COVERING PLEISTOCENE GRAVEL
For field description and analyses one is referred to table 30.4, profile
38.
a. M o r p h o l o g y .
(A ) 0-5 cm Platy structure (fig. 28), 2A++R+S°+, very thick plates of
12 mm subdivided in thin plates of 2 mm, surface porosity
18%, perimeter of aggregates 2,3 P-units.
(B)
5-19 cm Crumbly structure (fig. 29) of which are:
(a) 47 percent unaccomodated, 2A R S , surface porosity
28%, perimeter of aggregates 7,6 P-units;
(b) 2 percent partly accomodated, 2A R S , surface porossity 25%, perimeter of aggregates 5 P-units;
(c) 9 percent concentric, 2A R S , surface porostty
9, 5%, perimeter of aggregates 2,9 P-units;
(d) 42 percent reorganized a-b-c, 2A R S , surface porosity 18,3% perimeter of aggregates 5,6 P-units.
(K.) 19-50 cm Subangular blocky structure, 3A R S , surface porosity
19,3%, perimeter of aggregates 2, 8 P-units locally rich in
aggrotubules with unaccomodated aggregates, surface porosity 20, 0-25,6%, perimeter of aggregates 7,0-8,2 P-units.
(K„) 50-105cm Blocky structure, 3A R S , relatively porous with a sur-,
face porosity of 18,4% and a perimeter of aggregates of 4, 5
P-units to compact with respectively 11, 6% and 2, 7 P-units;
locally aggrotubules with unaccomodated aggregates.
The amount of coarse aggregates in the aggrotubules is increasing down166
wards in the soil profile.
A surface porosity of 46,6% and a perimeter of aggregates of 5 P-units
was met where the unaccomodated aggregates of aggrotubules were connected
by thin bridges of soil plasma.
b. M i c r o m o r p h o l o g y .
Skeleton grains are of silt and sand size; gravel occurs also. They have
an angular habit and are found at irregular distances from each other.
The grains are embedded in calcitic plasma and the associated micróvughs
are often filled with calcite or gypsum.
The plasma grains are of 3-10 n size or smaller, are closely packed together and the plasma is composed of clayandhighlyirregularcalcitemicrolites.
The characteristics of the different soil horizons are given below.
(A-1)
0-5 cm Calciasepic fabric with vughs and planes; 30 percent of the
soil plasma is built up of calcite microlites; vesicles separately or interconnected to planar voids; very few calcareous
glaebules, calcitans; few aggrotubules, some organic isotubules and mull accumulations; small sesquioxidic nodules
(approx. 5 3 p e r c m ^ .
(B)
5-19 cm Calciasepic fabric with vughs and channels; 36 percent of the
soil plasma is built up of calcite microlites; few calcareous
glaebules, calcitans; many aggrotubules, some organic isotubules and mull accumulations; small sesquioxidic nodules
(approx. 49 per cm ).
(K1)
19-50 cm Calciasepic fabric with vughs and channels; 40 percent of the
soil plasma is built up of calcite microlites; many calcareous glaebules, calcitans; many aggrotubules and some organic isotubules, mull accumulations; small sesquioxidic nodules (approx. 32 per c m ) ,
(K„)
50-105cm Calciasepic fabric with vughs and channels; 60-65 percent
of the soil plasma is built up of calcite microlites; many calcareous glaebules, calcitans; aggrotubules and some organic
isotubules, few mull accumulations; small sesquioxidic nodules (approx. 23 per cm ).
167
The calciasepic fabric (fig. 30) is characterized by plasma concentrations
that are:
— of calcitic nature surrounding skeletal grains;
— of clayey nature surrounding skeletal grains;
— of clayey nature surrounding places with a higher content of calcitic plasma.
c. O r g a n i z a t i o n
within the p e d o l o g i c a l
features.
The aggrotubules are built up of randomly packed aggregates. These often
have an angular habit but spheroidal and ellipsoidal aggregates were found.
The angular forms are the result of burrowing activity while the other are
faunal excreta. The latter are often composed of clay and humus and were found
throughout the soil matrix. Locally isotubules with randomly packed skeleton
grains and clay-humus plasma were found (fig. 31). Channel cutans of this
material occur also.
The calcareous glaebules have a concentric fabric on the outer sides
(fig. 32) but the internal fabric is essentially calciasepic (fig. 33).
The sesquioxidic nodules have a size of about 50-250 n. are irregular and
have an undifferentiated fabric.
2. TYPIC CALCIORTHIDS; HOLOCENE LOAM OF THE BALIKH
For field description and analyses one is referred to table 30.5, profile
37.
a. M o r p h o l o g y .
(A )
0-15 cm
Coarse, porous crumbly structure, 2A R S
; locally sub-
angular blocky structure, 3A R S , surface porosity 9% and
perimeter of aggregates 2, 3 P-units; few aggrotubules with
. unaccomodated aggregates ; few segmented striotubules (fig.
34), surface porosity 22,2% and perimeter of segments 2,4
P-units; locally unaccomodated aggregates connected by a
bridge of soil plasma with a surface porosity of 34% and a
perimeter of aggregates of 4,0 P-units.
(B)
15-32 cm Subangular
Subangular blocky structure, 3A +R
R+S O++ , surface porosity
11, 2%, perimeter of aggregates 2,6 P-units; few aggrotu-
168
bules with unaccomodated aggregates.
(K21)
32-63 cm Blocky structure, 3A R S°, surface porosity 20%, perimeter of aggregates 2,8 P-units; few aggrotubules with fine
and often coarse aggregates.
63-100cm Blocky structure (fig. 35) 3A ++ R + S 0+ , surface porosity 24%,
(K22)
perimeter of aggregates 3, 5 P-units; very few aggrotubules
with coarse aggregates.
The lime concretions have a very low surface porosity of 4,7%.
b.
Micromorphology.
Skeleton grains are of silt and sand size , have an angular habit, are
found at irregular distances from each other and are embedded in plasma or
have associated microvughs.
The plasma grains are of 3-12 p, size or smaller, have a highly irregular
habit and are closely packed together. The plasma is composed of clay and calcite.
The characteristics of the different soil horizons are given below:
(A..)
0-15 cm Calciasepic fabric with vughs and channels; 33 percent of
the soil plasma is built up of calcite microlites; calcareous
glaebules, calcitans; few aggrotubules and striotubules, few
to medium amount of mull accumulations ; small sesquioxidic
nodules (approx. 53 per cm ).
(B)
15-32 cm Calciasepic fabric with vughs and channels; 45 percent of
the soil plasma is built up of calcite microlites; calcareous glaebules, calcitans; many mull accumulations;
small sesquioxidic nodules (approx. 32 per cm ).
(KO1)
32-63 cm Calciasepic fabric with vughs and channels, 43 percent of
Ax
the soil plasma is built up of calcite microlites; many calcareous glaebules, calcitans; few aggrotubules filled up
with fine granular or coarse material, small sesquioxidic
nodules (approx. 31 per cm ).
(K22)
63-100cm Calciasepic fabric with vughs and channels; 43 percent of
the soil plasma is built up of calcite microlites, many calcareous glaebules, calcitans; few mull accumulations, small
sesquioxidic nodules (approx. 25 per cm ).
169
3.
TTPIC GYPSIORTHIDS
For field description and analyses one is referred to table 30.8, profile 13.
Intercalary gypsum crystals are 60-140 p,or larger. The plasma is composed
of argillaceous material and fine-grained gypsum and calcite.
Micromorphology:
(A)
0-15 cm Calciasepic to crystic fabric (fig. 36) with vughs and channels; granular aggregates (size 60-250 n) with calcareousargillaceous plasma are found throughout the soil matrix;
few calcareous glaebules, often with cracks impregnated
with gypsum; few aggro tubules, few mull accumulations;
few sesquans; calcitans and gypsans.
IIC^
15-45 cm Crystic to calciasepic fabric (fig. 37); few granular aggregates with a calcareous-argillaceous fabric; clay blocks,
often with cracks impregnated with gypsum; intercalary
gypsum crystals; calcitans and gypsans.
IIC-
45-90 cm Crystic to argillasepic fabric (fig. 38) with intercalary gypsum crystals and many clay blocks; grain argillans; calcitans and gypsans.
Micromorphology of gypsum crusts;
A gypsum crust has an allotriomorphic (Tyrrel 1956) crystic fabric showing anhedral crystals of gypsum (fig. 39).
Gypsum polygones are characterized by a parallel arranged crystic fabric,
(fig. 40). Small gypsum crystals are arranged parallel to the vertical sides of
the polygones while anhydritic skeletal grains have a random arrangement.
4.
TYPIC CAMBORTHIDS DEVELOPED IN LAPILLI MIXED WITH CALCAREOUS LOAM
For field description and analyses one is referred to table 30.9, profile 41.
The skeletal material is built up of lapilli, olivine (Volcano province),
feldspar and quartz (Terrace-Balikh province).
The soil plasma is builtupof calcareous-argillaceous material locally
mixed with soluble silica derived from volcanic glass.
The amorphous groundmass of weathered volcanic glass at the surface of
the lapilli grains has been coloured at many places due to accumulation of amorphous iron oxihydrate (fig. 41 and fig. 42).
170
Iron-rich silicon dioxide accumulated in the calcareous-argillaceous soil
plasma (fig. 42) and locally is partly coating skeleton grains.
A skelsepic fabric found in these soils is weakly striated and may be regarded to be the result of sedimentary processes. Rolling of lapilli and loamy
material due to wind action will result in orientation of the latter parallel to the
surface of the lapilli grains.
Micromorphology:
(B)
6-54 cm Skelsepic to calciasepic fabric with grain silans and calcitans,
few sesquans, small calcareous glaebules ; calcareous argillaceous plasma arranged parallel to the surface of skeleton
grains and lapilli (rounded lapilli grains have more s u r rounding parallel arranged material than angular grains do
have); very fine granular aggregates are found between zones with parallel arrangement.
C
54-92 cm Skelsepic to calciasepic fabric with calcitans and few grain
silans and sesquans; a primary stratification of lapilli and
granular loamy aggregates is present and there is a parallel
arrangement of calcareous-argillaceous plasma to the s u r face of lapilli grains.
1 mm
Fig, 28. Platy structure of a Typic Calciorthid; loam covering Pleistocene gravel
( thin section in plain light ).
171
••r?r^
• ^
w
*
• ••••
1 cm
Fig. 29. Crumbly structure of a Typic Calciorthid; loam covering Pleistocene gravel ( structure
photogram).
a. Un accomodated aggregates,
c. Concentric fabric.
b. Partly accomodated aggregates.
d. Reorganized a - b - c.
172
100
Fig. 30, Calciasepic fabric ( thin section under crossed niçois }.
a. Calcareous plasma with clayey admixture,
b . Argillaceous plasma with calcareous admixture.
c. Calcitans.
d. Voids.
e. Skeleton grains.
f. Mull accumulations.
173
250^
Fig. 31. Muil accumulation in ïsotubule (thin section under crossed niçois).
Fig. 32, Calcareous tjîaebule ( thin section under crossed niçois
174
250,
Fig. 33. Calciasepic fabric of calcareous giaebuies with caicitans. (thin section under crossed niçois).
1 cm
1 cm
Fig. 34. Striotubule and siibangular blocky
structure ( structure photo<|ram ].
Fig. 35. BlocKy structure { structure photogram).
175
500,
Fig. 36. Calciasepic to crystîc fabric ( thin sect ion under polarizer rotated through 30 ) with :
a. calcareous- argillaceous plasma;
b. gypseous - calcareous plasma with pores;
c. calcitans.
176
'1
1
II
il
II
II
800
Fig. 3 / . Crystic to calciasepic fabric ( thin section under crossed niçois ) with :
a. calcareous - argillaceous plasma;
b. gypseous - calcareous plasma with pores;
c. calcitans;
d. voids;
e. gypsans.
177
800 y,
Fig. 38. Crystic to argillasepic fabric { thin section in plain light ) with grain argillans.
800,
Fig. 39. Allo tri omorphic crystic fabric of a gypsum crust ( thin section under crossed niçois ).
178
800 p,
Fig. 40. Parallel arranged crystic fabric of gypsum polygones ( thin section under crossed niçois ).
80
Fig. 41. Accumulated amorphous iron oxihydcate at the surface of a lapilli grain ( thin section in
plain light ).
179
200 i
Fig. 42. Asepic fabric of lapilli mixed with calcareous loam ( thin section in plain light ).
a. Calcareous - argillaceous plasma with voids.
b. Opaque volcanic glass with augite and olivine microlites.
c. Light greenish grey volcanic glass.
d. Brown volcanic glass rich in iron oxihydrate.
e. Skeleton grains.
f. Calcareous - argillaceous plasma impregnated by brown iron oxihydrate. and silica.
g. Vesicles.
180
C H A P T E R IX
SOIL G E N E S I S IN THE BALIKH BASIN
The different soil forming processes and the resultant profile development
as related to time are dealt with in this chapter.
The rain water penetrating into the soil is either held by the soil particles
or moves upward again and evaporates at the soil surface or is transpirated by
the plants. The products of weathering are not removed from the soil through
leaching owing to the scanty rainfall.
The low amount of silicium and aluminum released from the primary minerals may furnish a skeleton for clay colloids. Iron compounds may be subject
to a mild reduction, however, oxidation is dominant and determines the soil
colour.
Alkali and alkaline earth are present in the soil solution in minor amounts
and largely determine the soil properties. While sodium and potassium disperse
clay colloids, calcium and magnesium have a high flocculating power and ensure
soil stability.
A. S o i l f o r m i n g
processes.
1 . SOIL PHYSICAL PROCESSES.
Alternate wetting and pronounced drying combined with the splitting action
of plant roots resulted in a fragmentation of loamy or clayey soil material and
the development of a blocky structure (Jongerius 1957).
A thin platy surface crust of one to five centimetres developed by the ac181
tion of raindrop impact (Mclntyre 1958) which causes the soil aggregates to
break down.
If dispersion takes place the finer material is washed into surface pores
and reduces their volume. Continued impact causes compression of the surface
producing a skin seal of about 0,1 mm thick. Where the soil air has been captured immediately under this seal, triaxial vesicles form and slight pressure
causes rupture into plate-like fragments parallel to the surface (Brewer 1964).
Excessive drying during the dry summer induces cracking of the surface crust.
In addition the repeated evaporation and wetting are factors which promote the
formation of a platy structure (Jongerius 1957).
Clayey soils in the alluvial plains are subject to intensive crack formation
due to alternate wetting and drying. Locally cracks up to 1 m depth are formed
During the summer some material of the (A) horizon falls into these cracks and
in the rainy season the soil material expands. Swelling pressure develops in
all directions and slickensides are formed in the horizon underlying the main
expanding layer (Dan, Yaalon 1966).
2 . SOIL BIOLOGICAL PROCESSES.
The upper five or ten centimeters of the ochric epipedon generally have
a carbon content of 0, 90 percent which rapidly drops below this depth to about
0, 30 percent. The carbon/nitrogen ratio of this surface layer is about 8. The
low carbon content and carbon/nitrogen ratio are due to:
— the sparsity of the plant residue ;
— the predominance of oxidizing decomposition due to high summer temperatures;
— the action of soil microflora (bacteria) and fauna (mites and insects).
During spring there is an intensive flush of vegetation and microbiological
activity depending on the conditions of temperature and moisture.
During this short period not only a new formation of humic substances but
also their subsequent decomposition will occur (Kononova 1961).
The biological processes in Typic Calciorthids on the terraces are discussed below.
Mites, insects and their larvae most probably caused the relatively intensive processes of redistribution of organic matter into deeper soil layers
(mull-accumulations) and the formation of a great number of aggrotubules (also
mammals could have played their part with the latter formation).
182
Under the platy surface layer a crumbly structure has been formed of
which 47 percent is unaccomodated due to the action of mainly burrowing soil
fauna, 2 percent partly accomodated and 9 percent concentric from mainly consuming soil fauna, the rest being reorganized.
Two different types of unaccomodated crumbly structure were observed,
these have :
— aggregates of various size and usually angular due to burrowing activities ;
— aggregates of nearly equal size and usually rounded (fecal pellets) due to
both burrowing and consuming activities.
The subangular blocky structure forms a transition between the biological
crumbly structure and the physical blocky structure, the blocky peds being
rounded on some edges by the activity of soil fauna and roots (Jongerius 1957).
The relation between subangular blocky structure and activity of roots and
soil fauna may be deduced from the following observations:
— a subangular blocky structure was observed between 25 cm and 40 cm;
— the roots of gramineae generally are restricted to the upper 10 cm. Below
this depth roots of shrubs have penetrated up to 40-60 cm;
— the activity of burrowing soil fauna is not restricted to the topsoil for aggrotubules were found also in the deeper subsoil.
Biological activity has not resulted in the formation of a pronounced crumbly top layer in Typic Calciorthids of the Balikh. However, the accumulation
of humus in deeper soil layers is greater than in soils on the terraces and the
occurrence of earthworm casts together with a relatively great quantity of
skeletal chitine indicate a rather high biological activity.
, Aggrotubules are more rapidly reorganized in these soils due to the greater
wetness thus leaving not much witness of the action of soil fauna.
The great influence of the rooting system on structure formation may be
deduced from the combination of a weak structure with a poor rooting system
in chemically and/or physically unfavourable soil layers. This was observed
in a loamy lapilli layer at a depth of 72 cm and in gypsiferous soil (53 percent
of gypsum) at a depth of 45 cm below the soil surface.
183
3 . SOIL CHEMICAL PROCESSES.
a. R e l a t i v e l y
soluble
constituents.
a.l. Calcium
carbonate.
Carbonates tend to accumulate between 40 cm and 70 cm below the soil
surface that is the average depth of penetrating moisture. The process causing
their mobility is the so-called carbonation which is active amongst others in
the presence of calcium and magnesium containing minerals.
Rain water passing through the atmosphere takes up a small amount of
carbon dioxide, and coming into soil more is supplied by oxidizing organic matter. The calcium carbonate reacts with the carbon dioxide containing soil water
and calcium bicarbonate forms which moves with the percolating water downwards in the soil profile. Practically pure precipitates of calcium carbonate
form when the carbon dioxide pressure in the soil solution decreases, this being
the case after percolation or capillary rise followed by evaporation of soil water.
Accumulations of this material were found in the following forms:
— calcareous glaebules;
— calcitans e.g. grain and channel cutans;
— impure calcareous accumulations in the soil matrix.
Deposition from carbonate-charged water results in an active aggradation
of irregular-shaped calcite microlites at many places in the soil matrix with
as a consequence a passive concentration of argillaceous material (calciasepic
fabric, fig. 30). With time the number of calcite microlites is increasing at
such places and more clay is pressed sidewards. The final stage is a glaebule
with a dense calcareous internal fabric enclosing some skeleton grains and
surrounded by argillaceous and calcareous zones which are arranged concentrically.
Below a cambic horizon from which carbonates are leached, a calcic
horizon developed during the arid Holocene. A petrocalcic horizon or carbonate
crust formed under more humid conditions during the Pleistocene. Rests of
this crust are found locally in terrace material where it cements gravel.
184
a.2. G y p s u m .
Gypsum having a moderate solubility of 2,6 grams per liter is easily
redistributed in the soil profile (fig. 26).
A gypsic horizon was found in many soils below the calcic horizon and at
its top some mottling occurs.
Gypsiorthids having a gypsum content of mo re than 25 percent are characterized generally by the occurence of a gypsumcrust (petrogypsic horizon) with
polygones.
Gypsum dehydrates into hemihydrate at a temperature of 38 C. This takes
place during summer when values of 42°C are reached in soil at a depth of 10
cm below the soil surface (chapter I, B, 3). Moistening during winter results
in hydration and solution of hemihydrate and subsequently the formation of a
hardened gypsumcrust with an allotriomorphic crystic fabric (fig. 39).
Its morphology is dependent on the degree of moistening. Thoroughly wetting results in the formation of a dense fine crystalline surface crust with vesicles and vughs as a result of the action of escaping air. However, less pronounced wetting leads to the development of a more porous crust accompanied
by cracks which have an irregular and locally hexagonal arrangement.
Excessive drying during summer causes renewed dehydration and formation of cracks often with a hexagonal pattern (such patterns were observed too
in weathered gypsum rock). During wet periods these cracks were filled up
with gypsum microlites which are arranged parallel to the sides (fig. 40).
Polygones thus formed are more resistant against solution processes than
the gypsumcrust owing to their vertical orientation. Therefore, they are found
often in places where the crust had been dissolved long ago.
There is an active migration of chemical constituents towards these polygones (e.g. Sabakh phenomena) and with increasing age they generally become
massive crystalline.
a . 3 . S o l u b l e s a l t s (more soluble in cold water than gypsum).
Soluble salts have been accumulated by percolating water in the deeper
subsoil or after subsequent evaporation in the topsoil.
Salt efflorescences are found at the. soil surface in:
— depressions of the Terrace region which are occasionally flooded by saltcontaining seepage water of higher grounds ;
— lapilli soils having a high sodium content;
— irrigated soils after inadequate application of water.
185
Sabakh phenomena, which are accumulations of calcium and magnesium
chlorides, were abundant in lapilli and gypsum soils, in the latter associated
with the occurrence of polygones . Thesesalts being hygroscopic appear as dark
patches at the soil surface in the morning if night dew occurred.
b. R e l a t i v e l y
insoluble
constituents.
Their mobility is low and therefore no diagnostic horizons characterized by them were formed.
b.l.
Silica.
About 30 percent of the quartz grains studied had a strongly weathered
appearance due to frosting as a result of corrosion and mechanical impact
during aeolian transport. This is generally known as a desert patina which can
be regarded tobeindicativeof the instability of this mineralunder arid conditions.
Keller (1958) states the following about the solubility of silicon dioxide of
aluminum silicate minerals: silicon dioxide is potentially soluble where the pH
at the hydrolizing interface of aluminium silicate minerals is 7-9,5 but its
solubility is low and large amounts of soil water must be available to remove
such silica in solution.
In arid regions the rate of hydrolysis is retarded owing to the scanty rainfall,but the high temperatures and the high pH, being about 8,6 in Calciorthids,
are favourable for dissolving of silica.
However, the high concentration of calcium and magnesium ions in the soil
solution results in flocculation of SiC* and A1_O and consequently lower their
mobility. In addition, the uptake of silica by plants in the topsoil and the formation of phytoliths (chapter V, A, 4) retards leaching of silica.
In spite of its low potential mobility under these conditions, the SiO2/Al2O„
ratio slightly increases downwards in the soil profile of Calciorthids indicating
some leaching of silica (fig. 23).
Silicon dioxide was found to be more mobile in lapilli soils (Camborthids)
with a high concentration of sodium in the soil solution, a pH value of 9, 0 and
an abundance of easily soluble volcanic glass. Iron-rich amorphous silicon
dioxide accumulated in the soil matrix which surrounds the lapilli grains rich
in volcanic glass (fig. 42).
186
b.2. S e s q u i o x i d e s .
Iron oxides and hydroxides are formed in situ from ferruginous minerals
by oxidation, hydration and hydrolysis. Oxidation is active during the greater
part of the year but hydration and hydrolysis only in the short rainy period.
For the mobilisation of sesquioxides in soils of arid regions, a protective
colloid is indispensable on account of the flocculating action of lime. Because
of the small amount of humus and its saturated state preventing it to function
as a protective colloid, silicic acid will be the only agent for this (Reifenberg
1947). There will be an optimum peptisation if the soil reaction is characterized by a high pH value, and a high content of alkali is promoting it.
Therefore, the chemical conditions in the alkaline Camborthids of the
Volcano region may be regarded to be favourable for this process. Amorphous
iron oxihydrate was found to be translocated over short distances in these soils,
(fig. 41 and 42). However , the precipitation is too low to cause significant
leaching of these substances.
While ferric oxides and hydroxides are only slowly soluble at a pH >3,
the ferro compounds can be dissolved at that pH range. Under the temporarily
wet conditions in soil they can be transported as ferro hydrocarbonates (Scheffer
und Schachtschabel 1960).
It may be concluded that three processes are active in weathering or mobilisation of iron compounds in arid soils, these are the protective colloidal
action of silicic acid, carbonation of ferro oxides and hydroxides with their
subsequent transport as ferro hydrocarbonates, and oxidation.
The hematite (aFe.O ) and wustite (FeO) found in the loamy material of
Li
O
Terrace-Balikh and Volcano regions (chapter m, A, 5, a) probably were partly
formed in soil after deposition. Wustite will be associated with temporarily
anaerobic conditions for which indications were found in the following forms:
— wet conditions in zones bordering the flood plain of the Balikh during a
great part of the year;
— a faint mottling at a depth of about 1 m often followed by a gypsic horizon
in Calciorthids of the Terrace region;
— sesquioxidic nodules in Calciorthids of the Terrace-Balikh region.
Drosdoff and Nikiforoff (1940; quoted by Brewer, 1964) suggested that sesquioxidic accretions are formed by an initial drying that causes concentration
of solutions in the small voids, thus initiating the formation of nuclei of deposition. This process may have played an important part in soils of the Balikh
187
Basin. Hematite may be formed from ferro oxides and hydroxides due to dehydration and/or oxidation processes during the dry season.
Conditions for translocation of aluminum oxides are less favourable, the
protective colloidal action of silicic acid being the only agent able to remove
it at the pH range of 8-9. At this pH one could expect a direct bauxitization;
however, the conditions for leaching of silica being unfavourable prevent a
concentration of alumina.
c. C l a y
minerals.
In dry climates the rate of hydrolysis is low due to the scanty rainfall and
therefore more time is necessary for a given reaction. There is an increase
in concentration of silicium, aluminum and other metal ions owing to evaporation of water from the weathering system. As the concentration of metal ions
builds up they may recombine at the energy level of the weathering environment
to form clay minerals (Keller, 1958).
The weathered residue of micas, pyroxenes and amphiboles may be converted in certain types of clay minerals (Van Schuylenborgh and Sänger 1950).
Keller and Frederickson (1952; quoted by Parfenova and Yarilova 1962)
pointed out the importance of the action of plant roots in liberating elements
of the crystal lattices of the primary minerals.
The elements thus liberated together with components of the soil solution, which
are derived from hydration, hydrolysis and carbonation, are partly absorbed
by the plants and subsequently returned to the soil with the plant residue, but in
a condition of higher chemical activity e.g. calcium oxalate, phytoliths (chapter
V, A, 4) and organometallic compounds. The fine rooting system of grasses is
regarded to be favourable for this process in having a large chemical active surface.
The mineralization of the plant residue leads to the synthesis of various
products including clay minerals.
The silica/alumina ratio of the clay fraction in soils of the Balikh Basin
generally is higher than 5 which corresponds to the high pH (>8).
Some clay has been formed in the (A) and (B) horizons. Palygorskite
was found to be cemented into clusters in these horizons (chapter VIII, A, 2),
this being due to weathering of this mineral which has led to the formation of
montmorillonite (chapter III, B, 2) in Calciorthids of the Terrace region.
Illite probably formed in the (A) horizons of Fluvents (table 30.3, profile 15)
188
and the top layers of Calciorthids (table 30.5, profile 37) from the Balikh region.
High pH values and high concentrations of magnesium and calcium are indispensable for formation of montmorillonite while high concentrations of potassium ions in the presence of calcium ions lead to the formation of illite.
The high calcium content of the soils has prevented the movement of clay
into underlying soil horizons.
The brown loamy material of the Aridisols originated from the Tertiairy
residue, both having palygorskite and illite as dominant minerals in the clay
fraction. Comparison of the state of weathering of the soil material with that
of the residue showed that weathering after deposition was low since the
deviations between these materials are relatively small.
B. Soil f o r m a t i o n
as r e l a t e d to t i m e .
For palaeo-climate^ne is referred to chapter I, A, 10 (table 10), for the
ages of the different deposits to chapter II, A, 2 and B, and for the history of
land use to chapter VI, 1.
The youngest soils found in the area are the Ustifluvents and Ustipsamments of the flood plains of Euphrates and Balikh which are Post-Medieval,
that is with a maximum age of 450 years. The Torrifluvents and Torripsamments of the lowest terrace of the Euphrates are prehistoric up to Byzantine
that is older than 1300 years.
st
The lowest terrace of the Balikh is older than the I
terrace of the Euphra-
tes, witness the tals build up between 5600 B.C. and 2500 B.C. The Calciorthids found on it correspond to this period while those developed in the loam
covering pleistocene gravel are older, that is Late WUrm-Preboreal-Boreal,
in having a/more pronounced profile development.
TheCàmborthids developed in the lapilli correspond in age to the beginning of the Holocene that is about 8500 B.C.
Deposition of proluvial gypsum took place at the start of the Pleistocene.
Since that time this deposit was attacked by weathering agents, resulting
in dissolving and redistribution of gypsum,witness karstic features and massive
crystalline gypsum polygones which may be regarded as palaeo-formations.
i
Gypsiorthids with powdery crusts and porous crystalline lenses were regarded to be rather recent formations under arid conditions.
The carbonate crusts found in the Lower and Middle Pleistocene gravel
bear witness of more intensive soil formation during Pleistocene times.
189
Soils will "grow upwards" if wind action and run-off result in accumulation
of material in the topsoil. That this happened with soils of the Balikh Basin is
shown by the repetition of calcic horizons in Calciorthids of the Terrace region
in depressions and valleys (appendix II). The accumulation of material does not
continue over long periods, so the soil will be left alone for some time enabling
it to reach a certain stage of development which is normally characterized by
the occurrence of a calcic and/or gypsic horizon.
There is some leaching of carbonates and weathering of minerals in the
(A) and (B) horizons of Aridisols which led to new formation of montmorillonite
and or illite.
Summarizing, it can be stated that in places where accumulation of material exeeded erosion of it, the arid conditions have led to the development of a
soil column with a thickness of several meters characterized by a repetition
of calcic and/or gypsic horizons, and an increased percentage of montmorillonite
and/or illite.
190
SUMMARY
This thesis contains a study of soil forming factors and genesis of the
soils occurring in the Balikh Basin (Jazirah, Syria).
The following sediments served as parent material for soil development:
— brown loams covering Pleistocene gravel or filling up valleys in the different regions;
— brown loams of the Balikh alluvial;
— sandy gypsum, the topsoils being mixed with loam;
— lapilli, the topsoils and subsoils being mixed with loam;
— loamy and sandy Euphrates alluvial.
Analyses were performed to obtain the following data in order to evaluate
soil genesis and to classify the soils:
— minéralogie composition of the different soil fractions<2 p., 5-10 p., 20-30 p.,
2-50 p., and 50-500 p.;
— soil analytical data of the fine earth <2 mm;
— chemical composition of the fractions < 2 P>, 5-10 p., 20-30 P- , and <2 mm.
The soil profile of the brown loams is rather homogeneous as regards
texture and mineralogical composition; they originated from the Tertiairy residue.
The acting climate is of the arid type with dry hot summers and cool relatively humid winters, the average yearly precipitation being 183 mm. Rainfall
has an aperiodic nature which malies dry farming a rather risky enterprise.
The Pleistocene was characterized by interpluvial and pluvial periods witness e.g. the terraces formed, the valley systems of the plateau lands and the
karstic features in proluvial gypsum deposits. The valleys of the plateaus serve
191
•at the present time as a drainage system for mud-loaded water after occasional
torrential rains.
Dust storms occur frequently as a result of aridity and high wind velocities.
There is accumulation of soil material in depressions and valleys due to
aeolic action and run-off processes.
Groundwater is generally saline and lies at a depth of about 20 m below
the plateaus. Fresh water occurs in the flood plain of the Euphrates.
Growth of plants is restricted to spring time. They rapidly complete their
life cycle during this time and then lie dormant in the form of seeds. Generally
there is a poor vegetation of mainly gramineae. Typical saline plants and weeds
occur in the Euphrates valley; shrubs are abundant in the Balikh valley; valleys
on the plateaus have their own characteristic type of vegetation in having more
bulbs and grass than their surroundings.
Soil fauna e.g. mites and insects redistribute organic matter into deeper
soil layers and markedly influence soil structure especially in the dry loams
of the terraces.
The soils were classified according to the "Soil classification, a comprehensive system, 7th approximation" (1960) with supplements (1964, 1967).
Fluvents, Orthents, Psamments, Calciorthids, Gypsiorthids (new great
group), Camborthids and Salorthids were encountered , and a soil map 1:50.000
was constructed.
The different soil forming processes are dealt with in the final chapter
about soil genesis e.g. the formation of calcareous glaebules, gypsum crust
and polygones, the accumulation of soluble salts, the mobility of silica and uptake of it by plants, mobility of sesquioxides and formation of nodules, the
formation of clay minerals in the (A) and (B) horizons , and soil formation as
related to time.
192
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PRELIMINARY DEFINITIONS, LEGEND AND CORRELATION TABLE TOR THE SOIL MAP O F THE WORLD. 1963. FAO, Rome.
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"196
Philadelphia.
C U R R I C U L U M VITAE
De schrijver van dit proefschrift behaalde in 1958 het diploma H. B. S. B aan
het Moller Lyceum te Bergen op Zoom. De studie in de geologie werd in
hetzelfde jaar begonnen aan de Rijksuniversiteit te Groningen. Het candidaatsexamen (Wis- en Natuurkunde i) werd aldaar in september 1961 met succes
afgelegd. Het doctoraal diploma (hoofdvakken bodemkunde en geologie, bijvak
sedimentologie) werd behaald in juni 1966 aan de Rijksuniversiteit te Utrecht.
Gedurende de periode februari 1965 tot mei 1966 was de schrijver werkzaam
als bodemkundige aan het Eufraat Project in Syrië. Na terugkomst volgden
werkzaamheden als leraar in de biologie en scheikunde aan het Möller
Lyceum te Bergen op Zoom gedurende het studiejaar '66-'67. Vanaf september
1967 was hij als assistent verbonden aan hetBodemkundig Instituut van
de Rijksuniversiteit te Utrecht.

the arid soils of the balikh basin (syria)

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