Field Guide - Geological Society of Australia

1972
FIELD CONFERENCE
ATHERTON TABLETAND
6lcAlRNS
HODGKINSON BASIN
OINNOT HOT SPRINGS
FIELD
CONFERENCE
ATHERTON TABLELAND
HODGKINSON BASIN
JUNE Lo - L2, L972
FOREWORD
Following upon the deviations offered by A. N. Z . A. A. S. in
there were many meetings both formal and informal at
the University of Queensland and several G. S.A. -sponsored fieLd
excursions accompanying the Congress, we revert to what has become
a traditional Queenf s Birthday weekend Divisional geological field
19?1 when
conference.
I am advised that the first such excursion was organised in
Divisional Committee fotlowing upon suggestions by
Binnert Haites and Carl Olsen.
1964 by the then
The Division has since organised annually, with the exception
of 1971 - A.N. Z.A.A.S. year, a Queensland field trip. This year,
commencing at Cairns, it is proposed to explore the geolory of the
Atherton Tableland. The trip will offer both geomorphological,
stratigraphic, and economic (tin) interest.
ln L972 we lick our wounds following the rrapid transit' of
geologic
booms within a decade, the early gas-oil of the midtwo
60ts and the metals boom of the turn of the decade. Fortunately
introspection rarely ails the prospector and overall an optimistic
reappraisal of our situation is about due.
Conservationists will perhaps become more objective and
divert some of their energies to the pressing problems of
environmental pollution. Geologists too will find in this expanding
field an increasing source of interest and employment during the
next decade. With this thought in mind may I wish success to the
field conference and on their behalf thank our many supporters from
government and industry for their generous financial support.
Gerald E. G. Sargent,
Chairman,
Queensland Division,
Geological Society of
Australia Incorporated.
CONTENTS
Page
GEOLOGICAL SOCIETY OF AUSTRALTA INCORPORATED
t
QUEENSLAND DIVISION OFFICE-BEARERS t972/ t973
2
FIELD CONFERENCE COMMITTEE
3
ACKNOWLEDGEIVIENT
4
ATHERTON TABLEI.AND - HODGKINSON BASIN AREA
5
Physiography
by R. M. Tucker, Pacminex Pty" Ltd.
,
5
Brisbane
Soils and Land Use
by G. G. Murtha, C. S.I. R. O.
of Soils, Townsville
Vegetation
by
Geological Notes on the
Hodgkinson Basin
L.I.
,
Division
Webb, and J. G. Tracey,
C. S. I. R. O. , Division of Plant
Industry, Brisbane
by R"M. Tucker, Pacminex Pty. Ltd.
Brisbane
'
Mining History
by R. M. Tucker, Pacminex Pty. Ltd" ,
Economic Geology
by R"M. Tucker, Pacminex Pty. Ltd"
14
'
Mineral Exploration in the by R, G. Taylor, Geology Departrnent,
District
13
Brisbane
Brisbane
HerbertonJVlount Garnet
10
t6
James Cook UniversitY of Nortlr
Queensland, Townsville
18
References
MAREEBA-DMBUTAH IRRIGATION PROJECT
by' The Queensland Irrigation and
Water SupPlY Commission
20
CONTENTS
Page
THE BARRON RIVER HYDRO-ELECTRIC SCHEME
by The Northem Electric Authority of
Queensland
26
ROUTE LOG
1
for Saturday tO.6.72
29
ROUTE LOG
2
for
Sunday Lt.6.72
30
ROUTE LOG
3
for
Monday
31
L2.6.72
PARTICIPANTS
32
ITINERARY
33
DIRECTORY OF SUPPORTERS
34
GEOLOGICAL SOCIETY OF AUSTRALIA INCORPORATED
The Geological Society of Australia was inaugurated during a meeting of Sectir
(now Section 3, Geology) of the Ausbalian and New Zealand Association for the Advan
ment of Science (A.N.Z.A.A. S. ) at Brisbane, in May, 1951. The organisational strur
of the Society is based on Divisions which correspond to the States of the Commonweal
with Commonwealth Territories forming one Division. The foundation meeting of the
Queensland Division took place in December, 7952. The Society was formally
incorporated in May, 1969.
The Society publishes a Joumal embodying conbibutions to the geological scier
At present, each volume of the Joumal is published annually, in four par8. Amongst t
18 volumes published to date, the geology of Western Australia (Vol, 4, Pt 2), Soutle
Australia (Vol. 5, Pt 2), Queensland (Vol. 7, PtZ), Western Papua (Vol. 8, Pt 1),
Tasmania (Vol. 9, Pt 2), andNew Soutl Wales (Vol. 16, Pt 1), has been comprehensi
treated, Three volumes in a series of Special Publications have also been published -I
(Census), No" 2 (Proceedings of the Specialistsr Meeting, Canberra, May 1968), and N
(Proceedings of the Symposium on Archaean Rocks, Perth, May 1970).
Several standing committees fiurction within the Society. The Stratigraphic
Nomenclature Committee administers the Code of Stratigraphic Nomenclature; the
Tectonic Map Committee produced a Tectonic Map of Australia (L:2,534,400) in 196C
one at a scale of 1:15r0001000 for incorporation in the Tectonic Map of the World, an
a Tectonic Map of Australia and New Guinea at a scale of 1:51 0OO, O0O, which was
released in April this year" Other committees are concemed with the recruitrnent,
training and employment trends of persons practising the geological sciences, and
collation of data for the drawing up of census statistics relating to such professionals.
There are approximately 2rtOO members in the Society, and membership in tlr
Queensland Division stood at 259 in April, 1972, The Society maintains contact with 8
universities and colleges, and 41 surveys" museums, and institutes located in various pa
of tfie world. Forty national and international oil and mining companies are corporate
subscribers to the Society" All persons and institutions engaged or interested in tfre
geological sciences are invited to make application to join the Society; perticularc
concerning membership may be obtained from the Federal or Divisional Secretaries.
ACKNOWLEDGEMENT
Since 1964 the Queensland Division field conferences have met
with remarkable success. This success has not been accidental; it is
largely due to the generous support of the exploration, mining, and
service companies, universities, and government institutions operating in
Queensland" Our supporters f.or 1972 are listed in the Directory of
Supporters at the rear of this volume.
The Field Conference Committee $atefully aclmowledges the
help and enthusiasm of the contributors to tfre text of tJris volume' It is
hoped that they will be rewarded by the interest evoked on the part of
the conference participants.
1
(
Finally our thanks is extended to Loloma Mining Corporation N.L.,
and to Ravenshoe Tin Dredging Limited, who
occasions during the conference.
will
be our hosts on two
s
1
T
t
l
I
(
l
I
ATHERTON TABLELAND
HODGKINSON BASIN AREAX
PHYSIOGRAPHY
The principal physiographic units in the region are:-
1)
(2)
the coastal plain;
(3)
the Palmer/Burdekin upland.
(
tlre scarp bounding the west uplands;
The Coastal Plain
In the region which the Conference will visit the coastal plain is nanow and in
the area north of Buchan Point it disappears completely. The plain is flat and thickly
alluviated, witJr some monadnocks. The area immediately north of Cairns Airport is
composed of coastal plain and is the widest development in tfre area.
The Boundary Scarp
The scarp is a sharp break-of-slope, usually steeper than 35o. The steepest
along the re-entants of the river gorges. Typical of this is the Barron Gorge
which has been cut in rocks of the Hodgkinson Formation. Waterfalls are common where
major streams cross the scarp and flow to the coast, Talus and piedmont deposits
generally flank the scarp.
slopes are
Upland
The upland area on the western side of the scarp is an irregular, discontinuous
belt of rugged mountains and tablelands, with the maximum elevation in the east.
Examples of the tablelands which will be seen during tJre Conference are tfie Hann
Tableland, to the north-west of Mareeba, and the Atherton Tableland. The development
of land forms in tleis region is largely dependent on underlying rock types.
Features of special geomorphologic interest are the volcanic vents and other land
forms of the Atherton Basalt Province. Several types of eruptive cenbes have been
preserved including cones, crater lakes and one diatreme,
SOILS
AND I.AND USE**
Inboduction
The only published soils map covering this area is sheet 7 of. the Adas of
soils. Very detailed mapping (Qld. Departrnent of Primary Industries
unpublished data) has been conducted in the Mareeba Dimbula irrigation areas. The
soils are closely correlated with the underlying geology but the pattem is confounded to
some degree by the very steep rainfall gradients experienced across the study area.
Ausbalian
The soil pattern that has been established by reconnaissance mapping is briefly
described for each of the
major geological formations.
* ByR.M, Tucker, Pacminex Pty, Ltd., Brisbane
** By G. G, Murtha, C. S. I. R. O. , Division of Soils,
Townsville.
5.
Atherton Basalt
Although rainfall ranges from approximately 4O to 180 inches morphologically-the
rreryoifo.*. They are all red friable earths, generally very deep in the high
rainfall are"i brrt only 7-2 m deep and.with variable amounts of coarse boulders on the
surface and throughout the solum ln the drier areas between Mareeba and Tolga. All t}re
soils are
high rainfall soilJ(Krasnozems) are very freely drained, slqongly leached, and have
*ilafy to sbongly acid reaction uends, The lower rainfall soils (Euchrozems) are generally
not as stongly leached and have neutral reaction trends.
Barron River and Hodgkinson metamorphics
The soil pattern here is somewhat more variable, soil development beingdependent to some degree on the nature of the underlying metamorphosed sediments. These
differences are-mote pronounced in the lower rainfall areas, Again wrder higher rainfall
the soils are very strongly leached and this negates to some extent parent material
influence. Soili rangJfrom yellow to yellowish red, and have uniform or gradational -textured profiles (red and yeliow podzolics, Xanthozem, Krasnozems). They are gen_erally
very freeiy draining, moderately deep to deep, and o_verlying very- deeply weathered
parint materials. In the drier areas shallow acid duplex soils_are dominant' Subsoil
iolours range from yellow ot brown, to red. Major associated soils are shallow gravelly
loams.
Mareeba Granite
The soils derived from Mareeba granite also occur under a wide rainfall range
from about 180 inches atMt. Bartle Frere to about 35 inches on the Hann Tableland.
In the high rainfall areas they are dominantly red friable gradationaltextured soils (Red
Podzolics, Krasnozem), with lesser similar bleached yellow soils (Yellow Podzolics Xanthozems). They are generally very deep and very freely draining. In the drier areas
shallow red massive earths and uniform sands are cornmon in areas of insitu soil development while deep red and yellow massive earths are dominant in areas of colluvial
accumulation.
Elizabeth Creek Granite
The soil pattern developed here is very similar to that on the Mareeba granite.
In the area between Atherton and Herberton the relationship between soil development
and rainfall can be seen on a fairly short fansect, Deep friable red and yellow eart}s
are dominant under rain forest while shallow red and yellow uniform sands and shallow
acid duplex soils occur under the drier Eucalypt forest. In the intermediate zone of
Casuarina-Eucalypt forest there is a complexity of soils, dominantly those of the wetter
areas but also including a range of uniform sands common to the drier areas.
Glen Gordon Volcanics
Deep to very deep yellow friable earths (Xanthozems) are again dominant in the
|righ rainfall areas. Red friable earths occur on more basic intrusives and shallow
gravelly loams on very steep slopes. In tfre drier areas shallow leached loams are
common on higher slopes, deep leached Ioams and sands on lower colluvial slopes, and
alkaline duplex soils occur in the valley floors, Red neuhal duplex soils occur on the
basic intrusives"
Soils formed on Alluvium
The soils formed on alluvium are generally extremely
variable. The chief
factors influencing their development are the kinds of parent material from which they
have developed and the age of the deposits.
On the coastal plain north of Cairns and in the alluvial corridor to the south they
all formed from a mixture of basalt, granite, and metamorphic rock materials,
Deep friable loams are dominant on the floodplains with loamy and sandy gradationaltextured soils on stream levees and a range of strongly gleyed soils and peats in swamps.
In the drier areas alkaline yellow duplex soils are common on the broad alluvial plains
are
with a range of loamy red and brown massive earths on the younger stream levees.
Land Use
There is a very wide diversity of land use in the study area, Sugar cane forms
in the coastal areas and is grown on a wide range of soils, Cane growing
utilizes almost all of the alluvial country and extends onto the gently sloping foot slopes
of t}le Coastal Ranges,
a mono-culture
On the basaltic soils of the Atherton Tableland dairying is generally resbicted to
tlle more strongly rurdulating areas while a range of crops, principally potatoes, maize,
and peanuts, are grown on the more gently undulating areas. Although tfiese soils are
initially very fertile, fertility levels drop very quickly under pasture or cropping'
Phosphorus is the most limiting plant nutient although in some areas molybdenrrm and
potassium responses may be obtained,
Tobacco is the chief crop in the irrigation area. Utilization of the drier areas is
restricted to beef cattle grazing of native pastures, The rain fores8 are an important
source of a range of structural and cabinet timbers.
VEGETATIOM
General
Average annual rainfall drops sharply westwards from tfre coast, especially in
rain-shadow areas of the high subcoastal mountains (3,0O0 - 5,000 ft. ), although frequer
mists augment rainfall on the summia of the latter" The range is from approx. 160 ins.
average annual rainfall near Innisfail and Babinda to 30 ins. near Mt. Garnet about
60 miles inland. This rainfall gradient is only broadly correlated with changes in
vegetation (from luxuriant closed vine forests on the coastal lowlands to pockets of
deiiduous vine thicket, popularly called rrturkey scrubsrr, and extensive open grassy_woo(
lands) farther west, bectusL of the control exerted by surface geology, soils, and wildfir<
Grassy woodlands and layered woodlands (with a well-developed shrub layer),
dominated by Eucalypts, Acacias, Casuarinas and other sclerophylls (hard-Iea,ved species
in fact occur otr acid metamorphic and granitic rocks even in the high rainfall coastal
belt" On similarly nutrient-deficient soils but with impeded drainage, sPecies of
Melaleuca (tea-tees) and sedges are prominent"
On the contlary, well-drained basaltic soils of high nutrient status supPorted
(before clearing) a complete cover of closed complex vine forest (tropical rain Iorest).
This rain foresf massif begins to fragment only at the 50-55 inch isohyets e" g. in the
neighbourhood of Atherton. The nartow and irregularly shaped belt of rain forest,
*
By L. J, Webb and
J^
G" Tracey,
C" S.I. R. O.
,
Division of Plant Industry, Brisbane.
.
l|;S.tlC from co-mplex to-simple- types- depending on soil parent material and altitude,
15-40 miles wide in tbe Cairns hinterland.
is
- _ _ Topography is important in relation to wildfires which penetrate westem slopes
and ridges and spurs, and which favour the regeneration of fire^-tolerant Eucalypts aid
other_sclerophylls at the expense of the fire-s6nsitive rain forest species. Top'oiraphy
in sedentary o'r transporteh rilti tt"predominantly acid rocla: in such situations, rain forest is restricted toiheltered moist
also dictates the concentration of mineral nutrients
gullies, well-drained alluvium or colluvium, and riverine levees influenced by pa.ent
materials from basic and sub-basic rocks.
Soils exclusively from acid rocks and places where topography does not allow
accession of mineral nubients are occupied by open grassy wood'landi and layered woodlands which are bumt every few years, ;ven in tire w"et coastal belt. In drier inland
below 50-55 ins. aunual rainfall, sclerophyll woodlands replace rain forest on
,fire-shadoiusi' e. g. bourdery'outcrops or gullies.
!1sal!1c soils exce^pt in topographic
The "Forty--mile,ScrubI wesi oiMt. Garnet is an excStional reiic, not'thus
f,rotected,
of previously widespread vine forests on basaltic red soils.
-areas,
in t}le- region traversed is therefore closely
, . The- general pattern- of .vegetation
related to the interaction oj soil
plrent materials (irineral composition, witi phosphorus
and calcium status especially important), position on and
of slope, soif aep'tt aoa
"rp..i
stoniness, and soil drainage.
Cairns to Mossman via Cook Highwav
- -. Layered
woodlands-on slop-es and ridges on acid metamorphics and solodic or
!L.,*,"'*","1:n'trr:
?#"??;;;",r,,
and shrubs such as Acac-ia flavescens, A. aulacocarpa var. macrocarpa. planchonia"cai#a
(cocky apple) and one ofEEzarnTa
dense tea-tree (Melaleuca
ueneryia] often festooned by the fem Stenochlaena, and
with
many sedges.
seclges. Drooping,tea*hee
D-roop
paly
(M. leucadendron) and silver-le-if-tEEEi'
ITn
(V..9ealbata) favour seaionil fresh-watGilffiilli?ftiEndy soils behind the beach.
;aE;lG;s;Ait.
ffi1tr""affi
Ivluddy estueries and river-mout}s support about^twenty-five species of mangroves i.
e,
plants adapted to regular inundation-by tJre sea.
The well-drained levees of permanent steams support strips of complex mesophyll
vine forest with many bee sp_ecies, Lmong which are r.rrrriity pr"trii"""iui;[k t-";;--'"'-(9ast?nosperr?urr.r), penda lkanthostemoni, spur-wood arrd ,oie-woods (Dysoxylum).
P1ccabeenparm(Archontophoenixalexa'andstem-clusteringtis@9Eel'
.Lj-r--19r,rg.tY. *roP, (granites) along-the Cook Highway there are patches of vine
thlcl{et(related to those farther inland and in Cape York Peninsu-la) witir many deciduous
species, and some with showy flowers e. g, cochiospermum (yellow) arrd Bom'bax
a;;;i.--
,
on upper slopes and-gurlies, closed vine forest occurs, with many commercial
etg. n1tj1e oaks{fimily Froteaceae); silk-wood,
(Flindersia);
S]b."tt,
kaurr prne (4.ggttris); mackay cedar (Albizia and sovereid wo6a
"
""tt"-r,i"tory
( Ter;in;Tiat)
Mossman to Mareeba
via Rex Highwav
Layered woodlands of tlre lowerstropes^are replaced by closed vine forest
ascending
the range, but there ir.
T"* secondary rain forest a'o-i""t"i tf.'""ta", (Acacia spp, ).
t"ll,t"I"p1.illa (Alphitonla), l"*b kurrajong (commersonia),'
*ottffrtoiir "
muelleriana) and tangles of the large lawyer vinFF6Eiii3i-eil, "lil-r.
vines lcalamffi6ii
8.
i1 mole. mature stages of the forest succession, Fan palms (Licuala
T.l^fif,r:glli:)_
muellerl) are prominent in patches in the mature rain forest" Wattles'are
emergents,
"h on isti"
.especially on_spurs, reflecting the low*nuhient status of the soils
metamorphics, and past disruption of the-rain forest canopy uy .y"r"i"r, alowing
the
wattle-s to regenerate, This rainJore-st type contains
.*ri"r.i"r't-u"r;;?.t*
(see above), but when cleared, the sropei are rapidly-""'y
i""Ja"J-tf-*"ody weeds, [;;;il"
fem, I'sourl' gresses, etc,
Near Bushy Creek, cadagi (Eucalyptus torelliana) is notable, with iits greenish
half-barked
rked gum
gum-tree
bole
e and larg?TiA1iTeaG;lese;bling thos
- tree bol
those
e of ;;i;
rain forest hees.
It is adapted
rpted to regenerating only along
a1o"g thl
th! disturbed
disturbeJ edse
;eF;ith"
of"the ;iical
t "i i"rain forest.
""i.
In the Mt, Motloy area and towards M1.S"q"-,
_the vegetation is mainly low
layered woodland or low open forest dominated by tut"t"t"rr."'.rririalflora
and is typical
of much of the Peninsula country to_ the north o" iol6-did
lypts irli;;;-
t,r=ff
ifi
(E'
ffi
*Ifu
ry9";:**mr-ul;;;;;
occTiiiliavelly
s,taige-ri-ana)
ironbark (E' culleni)
_an_d
Patc-hes oJ Bull oak (ca.suarjnaJil&li-iiiii) and
on the solodic
forest.
t$*:l
=ril'"Ti:ffi
ridges, There are also small
tin;-teaf L"-;;;,;"Ialeuca minutifotia)
flats. -TEeTlvd-i6isiigs-. g.
irr"" rl-riffi'
^ait:,heir,
south of Mareeba, the ilpeninsura country, continues for a few miles
along the
sr.,.u txees and
:.l9,,with lavered box-bloodwood wooirand, .;t;.;;i".ii
lT:::"'1*.i:*g;"^"'+F+q'
'c.-;6;;'ii;ii;,"s-iiC
--s;td;E-ffi
A;"rfo'iffi irJ""ffi
still
stil
"Acacia4avgscGns,-EE-LiGitas-fr
4n ure Lerrg,ue or Af,netIon
-_-_ --- r evvv--v, vs!.
Dasal6 fS feaChed,
the
community becomes .a grassy,woodtand,
grassy woodland"
dominated uy
bw box_blooawood,
hox-hlnarrwnn;r iui
1,,,+ wit]rout
,^
:]T,T-T'"%P:::Tf
sclerophyll
layei,
*ig a grass-forb layer of diff;"t;;t;;i;'.;;;;i;;
a,
-shmb-
:11:"1?t-l{9e
T-d
s-o--lggics. Cleared rai-n.forest on
bas_altic,"JrJi is-eircou.rterea iust
irrtfr",
tlr" ;;;;;i
"1""g (Ep
quandong
+l?,!".T1,rmum australe),
"prgzeg-cr"4rg,
andGfEEEi
is an interesting remnant
l..ll:lT_.lg:,
Atherton,
with red fulip oak (A
a1d. tfi.ere
milky pine (Alstonia scholarifi
an(
(Pvsgxvlqm sppJ
2
t (Aleurites) a
te
are common
jl*:t:I.,""1.:lgZ:1trre-.lwv.{vineisf ish_taii"J1ffi*-"".l,otoia"rr.along
;1:
Forest
red gum (Eucal
a stringybark (E.
tfierrSeven
t",t
*i
S
Ascendi:g-the Herberton
succeeded by.tall. layered
) oc curs on pa tch e s oi6i-s aiE-cTIiEEEiffi
",,"Ff y singles out acid volcanic outcrops,
e.
g,
s, and
near
(R 99) west of Atherton, the grassy woodrand is
forest Ll'gu
( "wEt sclerophyll
fo.esti;t;ith'cviii" messmate
(?usalrptus=cloe=zian
(lucalyptus cloeziana),
), turpentine ((Syncarpia slomulifera)
hi-1,.
- end ai
somewhat higher
i{9le),_and
^i so^mawlrrt
a-llltud-es,-T-e_E
4rlrfuqes' f,ne Ea.,
lT;,Ti
wnrEe-b_orecl
te - U6l e a trooderl gum (8. grqndis)-. T!r" rain
foresB are simpler
in stmcture than those on basal8, and w-ith ilG;ffiLg-altitude
titude above about
atout g.
3, OO0
OOO {t.,
{t..
#;;":i:J;;:tr*,1i#,i"i';.n
*-::.:!{l;;t;-t'tt";;"-;;;i.,;h"d;;i*-i.Hff
reduction in leaf size and tee heighi, smoothness%i;;;6t;l;;;;;;;";;r;;;
as
appearance or
of the palm,C_alyptrocalvx.ausEalasigus.
palm Cal
The
forests on these granitic soils
contain-manycommerci@clearedt}esoiiierti1itvissoon
fertility is soon
lost and erosion and weed invasion iottowl
West of the rain forests of tfre Herberton Range and with lowered rainfall (below
4o ins',) there areJayered woodlands with ironbark, Eloodwood, g"*r,
,"a
stunted silver-leaf ironbark (E. shirleyi) and the yellow-barked ti".Jri,.J
not uiy *re
G.-e.l*Et
on the return from Mt. Garnet, there is much cleared rain forest and wet
sclerophyll forest counby on mixtures of basaltic and rhyolitic ,o"lo ,r"r1. Ravenshoe
and
9.
towards the Crater on tl:e Atherton road, Degraded country with dense weed invasion and
erosion is correlated with steep slopes, or with preponderance of rhyolites,
GEOLOGICAL NOTES
ON THE HODGKINSON BASIN*
Summary
The area which will be covered by_the Excursion is the south-eastern portion of
the-Hodgkinson Basin which is a north/north-west trending trough of Lower palaeozoic
sediments and volcanics witlin the Tasman Geosyncline.- The'depositional limia of the
-margin
Basin in the east are not known, and the westem
of the Baiin is bounded by the
Palmerville Fault. Sediments in this region (Chillag6e Formation) include reef limestones
and other shallow-water deposits, and indicate that the structural 6oundary and the
dep_ositional b_oundary are approximately the
same. Sedimentation in the'Basin commenced
in-the Upper Silurian and is tleought to have continued at least to the end of the Devonian,
Palaeontological evidence (quoted in deKeyser and Lucas, 1968) indicates tfrat the
up-p-erm-ost age of sedimentation may not be accurately known. The sediments were
rlded_by_strong
folded
by strong comPressive
compressive forces from the north-eait
north-east prior
Drior to the
extnrsion of thc
tlee extrusion
the
pPer Pa-laeozoic volcanics" These acid extrusives which have been investigated in detail
(1966)
are
unconformable
,r-Branch
upon the sedimen8 of the Hodgkinson Bisin,
nentetion after the Devonian was of resticted occumence only] the Silver valley
Iomerate (which will not be visited) is the best known unit" bbal measures of
pper Permian age unconformably lay upon the Hodgkinson Formation at Mt. Mulligan
od are in tum overlain by Triassic sandstone. Outside the area visited Upper Mesoz-oic
ts of the Laura Basin and the Carpentaria Basin overlie t}le Hodgkiirion Formation.
and Geo
I His
The sediments of the Hodgkinson Basin occur in a belt over 200 miles in length
u up
uP to
100 mlles
Le rvu
miles ln
in width.
wlqrn. In tfie
the soutir-east
south-east the Hodgkinson Formation grades into
in-to the
rron River Metamorphic-s,
_which ogcupy an area of solie 2,000 square miles. The
al outcrop area of the Hodgkinson Formation would approach 20, o00 sq. miles.
Th-e Hodgkinson Formation i"" a highly folded, thick geoslmclinal deposit of
ically drLcruaLurl4
alternating alellLe
arenite an(l
and slaf,e,
slate, wlur
with rntercalatecl
intercalated"beds
becls of chert,
chert. 'volcani
volcanics,
limestone. The Formation is p-robably several tens of thousands of feei thick,
ever, its sructural complexity has prevented an accurate measurement of its
(1970)^has
propose! ttrat-the-chillagoe, Mt. Gamet and Ringrose Formations
. ll_ake
t],e Montalbion sandstone,,instead of being Gp.!"1u depositional ,rrrit", .r. merely
cies variations witfrin th9 H-gdg\inson Formadon."These^rocla appear to fo"- a sinile
rnformable sequence of similar
types and are consider'ei by the author
mapped as one formation.
"
1t_F"_t"gilql
(BIake I97Ol.
to"be
In the west of the Basin the reef limestones, clastic sediments, and volcanic
of the Chillagge and Mt. Gamet Formations are considered to rdpresent a near-shore,
llow-water, shelf environment. The interbedded arenite
rfat"'oi the Hodgkinson
""a to represent an oif-shore,
mation in the type area (Hodgkinson Goldfield) is considered
water basin where depositio;r by density cunents was common. -DeKeyser and
(1968) describe and{igure bottom stuctures, including sole markings, lode
casts
groove casb-.- They-also reported that graded-bedding iiwell a";;ifta in the thin
medium bedded rocla.
By
R.M, Tucker, Pacminex pty. Ltd,,
Brisbane
The age of the sediments varies from upper Silurian in the west to upper
Devonian in the east and it is possible tfrat sedimentation wai noicontinuous
throughout
the Basin for the entire period,- The rocks of the Monalbion s"rrarioo"
and Ringrose
Fo.rmation w-er-e f99n{, during detailed map_ping in the Herbetto"
.r"", to be inter-bedded
with rocla of the- Hodgkinson Formation, i'ir"y
quart-rich rocks and are much more
resistant to weatJrering than the greywackes, and""e
the'refore stana out as prominent ridges
well above the surrounding rocla.
This
tlick
Lower Palaeozoic sequ_ence represen8
the entire depositional phase of
-in north eueeisland. i.r," ,"q"""."
j9ln:::
a
oeposrtronal 9:::f_.lil"
environments from
""i,irl# rul ,anie oi
shelf to deep_sea.
contacts with all y_ounger rocks are unconformable and the sedimen8
intruded by the Elizabeth Cree[ and Mareeba Granites both oi c.rlo"ir"ro,r, have- been
ih;intrusion of the Mareeba Granite is considered to be post-forar"g" ---";;.
Source of the sediments deposited in the Hodgkinson Formation is considered
tie Georgeto"n, Ittli"t wittr somE additi;; ;i;;;remporaneous to
be the older rocks of
volcanic material.
Upper Palaeozoic Igneous Rocls
- - After the folding in the Lower Carboniferous,
-Hodgkinson Basin and their borderrand
the geosynclinal sediments of the
were invaded'by d"i#t-;;;
iarge vorumes of
acid and intermediate volcanic rocks were exbuded"
Volcanic rocks of carboniferous to permian age are widespread in the caims
hi::terland' Thirteen formations have been named, Ji *rri.r, troi-*re cien
Gordon
Vo.tcanics, occyr
-d i".thtAtr,;o,,'i"ulerr,ra ,"giion, The
Y,",1.::t;,l*;|:_y1t-rl-B]uff
silver
Valleyconglomerate,. which-cropr ont miles sourhwest H;;;;;;;:ilJ
included by Blake (1970)
(1970\ under this
"f
rhis heaiino.
heading.
"rrl
which are in the main of rhyodacitic composition, but also
T_"::.:d"""jcs.,
rhyolite, andesite,, and hachyandesite, are considered by Bianch igoo; to ue
associated with cauldron subsidence areas"
aieas" They overlie tfre
th" Uodgki;on
H#ckil;i"r*]1r""
Formation *i*
rhe main mass of cte; co;d;; fu;;il;;"ps out mainryw
to
:"T.1.1\".13"?1f-?'-jy.
the westand south of the Atherton_Tableland, and is well-exposed in r6ad
cu6 west of
Ravenshoe. It includes welded tuff, lava flows, agglom"""t6,
as well as some
sandstone and silstone. Dips range up to 3oo" onl|"one distintt,h"-.d";r;;;;
"rra-torr,
rudPPc_s, a
;:;ia,;'ry;idH;fi"";#:;".,:ff"y#f
roruerly Prungrng s)mclrne northwest of Ravenshoe.
ifi"::'#:'bHT""j*:o'"",""i
This is considered to
." Io.
'"ipp".dfto the formation
related
!_^r-_r^
rnclude
1
is
of the Glen Gordon Cau.ldron of Btanch tfgOOl. The formation
intuded by the Elizabeth creek Granite, but carries ,ro
mineral a"posits.
".orrorrti"
The
rne Walsh
warsh llutr
Bluff Volcanics
volcanics occur as a triangular
tr
mass west of Atherton, and
comprise.lava
ue.lplrre
rava rrows,
flows, weroeo
welded tuTl^agg*ro*erate^a-n-d tuff, which are dominantry acidic
aci
in
.tulfa.agg^lomerate^anr
D_ips range up to 30o.- Branch (1966) coniidered
composition.
considored that
rhrl rha
rn,*a+i^- ;is
the formation
:omp:s:tion.- Dips
the
Elizabeth
Cieek
Granite,
but
iltrt 1968) described I section east of
i"S9"{.9f
Collins Weir in which the basal bedded tuff overliei
"'( the dlizabeth Cre"t Granite with an
yncoqfoJpity, The formation is intruded by the Lower Permi"" W"t"Lrrile Granite and
is probably of Early
Permian age.
The Silver Valley Conglomerate outcrops in the old mining locality of Silver
valley 9 miles southwest of He-rberron" It is orily- r f"* ;q;";";;i";1" area,
but it is
of particular interest by reason of its unique lithology, *h'i;t il;;,_ried
some
collto-versy' The formation is no more than 3OO ft:'dihick and is made up of conglomerrte, thin sandstone, and siltstone containing plantfossils,
w"tirs *inor tuffs, The
"s
11,
conglomerate is massive and poorly sorted and contains lenses of tuffaceous sandstone'
The class in the conglomerate, which is characteristically purplish brown, are as a rule
less than 6 in. in maximum dimension, but boulders of 1 ft. or mole ate common, and
some are over 6 ft, Megaclasb ale well-Iounded. Reid (1933) rePorted that some
boulders were soled and faceted, but later workers have been unable to verify this
observation" Megaclas8 are dominantly of greywacke and obviously derived from the
Hodgkinson Formation, but volcanic rocls are also present.
Fossils from the carbonaceous siltstone in the formation have been determined
Rhacopteris, Cardiopteris, Aneimites, and Pitys, indicating a Carboniferous age.
According to Blake (1968) the Silver Valley Conglomerate is conformably overlain by
the Glen Gordon Volcanics and is therefore pre-Elizabeth Creek Granite, but not
as
mineralized.
Reid ( 1933) considered that some of the thin-bedded silts resemble varves.
in the conglomerate he concluded that the deposit was of glacial origin. On the other hand Blake ( 19 68)
drew attention to the tuffaceons, rather than clayey nature of the matrix and concluded
that the conglomerate is a fanglomerate deposited in alluvial fans in a narrow valley or
basin bounded by hills made up of contemporaneous acid volcanics and older rocks.
Because of this and the reported occumence of soled and faceted boulders
Granites
The Mareeba Granite comprises a number of separate intmsions, some large and
stocl.s. In composition it ranges from granodiorite to granite,
ofhers occurring as smaller
but is mainly adamellite,
It is grey, porphyritic, medium-to coarse-grained,
and
contains biotite and subordinate muscovite, Isotopic dating indicates that the Mareeba
Granite is younger than the Elizabetfr Creek and Herbert River Granites.
Elizabeth Creek Granite - There are meny scattered exposures with an aggregate
alea of about 2,000 square miles. The typical Elizabeth Creek Granite is orange-red to
salmon pink; it is medium-grained and equigranular, grading in places to porphyritic
microgranite and coarse pegmatitic granite. It is essentially a quartz-feldspar rock with
minor
biotite. It contains pipe-like
and lenticular bodies of greisen, usually witfr some
cassiterite; fluorspar is a common constituent.
According to Blake ( 1968) the Elizabeth Creek Granite is richly mineralised, and
is considered to be responsible for mo6t, if not all, of the mineralisation in the Herberton
Tinfield.
The Elizabeth Creek Granite has been dated at 280 m.y, and 326 m.y, (Blake'
1970) and is believed to have been injected during mid-Carboniferous to Early Permian
time.
The granitic mass north of Waaonville which was mapped by Best ( 1960) as
Herbert River Granite has been renamed by Blake (t97O). This mass is similar in
composition and age to the Mareeba Granite and could be referred to the Mareeba
Granite,
Basalt
The Atherton Basalt Province extends from Mareeba south to the Tully River, and
to Innisfail and contains flows and pyroclastic deposia covering rouglrly 70O square
miles. Most of tfie basalts occur in the northem part of tfre Atherton Tableland but some
flows descended the valleys towards the coastal plain, The province also includes a few
small basalts associated with eruptive centres in tJre coastal plain.
east
12.
About 50 ven8 have been recognised in the field or on the air-photographs"
They include shield volcanoes, composite volcanoes, cinder cones,
miars, lnd
one
diabeme. Most of the lava vents are concentrated in the south and west of the province,
and the cinder cones in the north, whereas the maars occupy a central belt" In several
localities, the topography and distribution of the basals indicate the presence of eroded
centes of eruption, as for example southeast of Ravenshoe, west of Babinda, and possibly
on the
Atherton Tableland.
DeKeyser and Lucas, in discussing the age of the Atherton Basalt, stated tJrat:direct evidence of the age of the basalts in the Atherton Province, but they
have a corsiderable range; tfre earlier flows have been dissected to a depth of about
1,300 ft, by the North Johnstone River and Toohey Creek; later lavas flowed down these
deep valleys and were zubsequently dissected to a depth of 5O to 100 ft" Along several
sbeams on the western side of the province, small weathered outliers of basalt crop out
on the hillsides 200 to 3OO ft" above the basalt on the floors of tlle valleys. The older
shield volcanoes have been much more deeply eroded than the later well preserved
rrThere is no
cinder cones"
The age of the Atherton Basalt probably ranges from late (?) Miocene or Pliocene
to Recent" Skertchly (1899) referred to the Atherton Basalt as Pliocene or younger, and
Jardine (1925) considered the crater lakes andMount Quincan to be post-Pleistocene.
Jack and Etheridge (L892) distinguished two phases of vulcanism in the Atherton Province,
therplugsr(cinder cones) belonging to the older, and the crater lakes to the younger
group.
On the western side of the Atherton Province, in the Mount Garnet district, many
of the older flows are buried under alluvial deposits to a depth of 130 ft, The presence
of pebbles of Cainozoic basalt in the gravels underlying the lateritic duricrust in Return
Creek indicates that the volcanic activity extends back to at least mid-Tertiary time.
In general, the vulcanism in the Atherton Province evolved from an initial
flows. The centres
of activity shifted gradually from the south-west to the nortlr-east, and Mount Quincan,
the Seven Sisters, the crater lakes, and Green Hill probably represent the latest
lavarich stage to an increasingly explosive gas-rich stage with few
eruptions,tl
MINING HISTORY*
The first mining activity in the Hodgkinson Basin was tlre commencement of gold
mining in 1873, Following tlee reported discovery of gold by the Hann Expedition,
J.V. Mulligan and party-discovered gold on the Palmer River at the site of the township
of Maytown. Furtler gold discoveries were made at a number of localities in the region,
notably the Hodgkinson Goldfield east of Mt, Mulligan. Gold production continued from
the 1870ts up until World War I I but the principal activity and production occurred in
the period immediately following the discoveries up until the early 19OOts.
The next phase of mining development was simultaneous with the gold mining
era. This was the discovery of tin in the Wild River in 1879 which led to the rapid
developmmt of the tin mining cenbes of Herberton, Wabonville, Stannary Hills and
Irvinebank; t}le silver lead deposia at Silver Valley and Montalbion, the copper deposits
atMt, Gamet and Mt. Molloy, the base metal deposits of Chillagoe and Mungana, the
wolfram and molybdenite of Wolfram Camp and Bamford and the wolfram at Mt" Carbine,
*
By
R,M. Tucker, Pacminex Pty. Ltd.,
Brisbane"
13.
Most of the major mineral finds in the region were made in the period L87O to
centre. Prior to the construction of a
railway from Cairns to the west, Port Douglas, near Mossman, was the principal port for
the area" Railways were built from Mt. Garnet and Chillagoe to connect with the Cairns
to Mareeba line and by 1910 Cairns was the principal outlet for the mineral production
of the region. A narrow gauge railway was built from Stannary Hills to connect with the
Cairns-Chillagoe railway and this was subsequently extended to Irvinebank. This narrow
gauge line operated until the outbreak of World War I I "
1900 and t}le region rapidly became the major
Several smelters and a number of batteries (both for gold and tin recovery) were
erected at mining centes throughout the region, These included the copper and lead
smelters at Chillagoe, copper smelters at Mt. Molloy and Mt. Garnet and a tin smelter
at lrvinebank" All of these smelters have been demolished and the only treatnent works
in the region are tin-batteries.
Principal activity and production in the region occurred in the period t88O/1920.
Activities received a severe set-back with the fall in metal prices after World War I which
was aggravated by indushial disputes and other problems. The area languished r:ntil the
commencing of dredging of alluvial tin deposits in 1939. Dredging has continued up to
the present time although Zimmerman ( 1965) suggested that reserves would be largely
exhausted by the mid 70's.
ECONOMIC GEOLOGY*
Mineralisation
Mineralisation in the region, with few exceptions, is genetically associated with
tfie late Palaeozoic intusives. The tin, tungsten, molybdenum mineralisation is
associated with the Elizabeth Creek Granite over much of its exposure. Base metal
deposits are concentated along the south-western margin of the Hodgkinson Basin and in
the pre-Cambrian shield.
Sbuctural"conhol of mineralisation within deposia has been suggested especially
for the tin ores of the Herberton area although it is most likely tleat the overall location
of the ore deposits is principally controlled by the intrusives. Blake ( 1970) describes a
disbict zoning in the Herberton area from the Elizabeth Creek Granite outwards into the
colmtry rock. Mineralisation associated with the Mareeba Granite is principally the
wolfram deposit at Mt. Carbine and tin-wolfram deposits at Cannibal Creek. All other
mineralisation is considered to be genetically related to the Elizabeth Creek Granite.
Most of the deposits are of high temperature-hydrothermal character although the
utinron)rl ind ld$deposis are low temperature- epithermal depooits.
The principal ores produced are those of
silver, lead together with gold and antimony.
tin,
tungsten, molybdenum, copper,
Tin Deposits
Blake ( 197O) has described tlle tin mineralisation in the Herberton Tinfield.
Broadly, mineralisation occurs as cassiterite associated with zulphides within the
Elizabeth Creek Granite or in tlre contact zone surrounding the granite. Several subdivisions have been erected on the basis of detail of occurrence; however, the principal
lodes within the granite occur within highly altered zones of greisen or similar rocks.
Lodes in sedimen8 are the chlorite-quartz lodes, many of which occur in shears.
ByR.M. Tucker, Pacminex Pty.
Brisbane.
I
Blake (1968); describing the mineralisation in the Herberton area states - rrln tfie
Tinfield economic mineralisation is widespread in rocls of the Hodgkinson
Formation and in tlee Elizabeth Creek Granite, and also occurs in Pre-cambrian rocks at
Mount Garnet, in Featherbed Volcanics near Stannary Hills, in Nanyeta Volcanics on
Mount Gamet and in an unnamed granite cropping out between Mount Gamet and Innot
Hot Springs. The mineralisation is considered to be associated with the inhusion of the
Elizabeth Creek Granite, This is indicated by the restriction of mineralisation to within
the Elizabeth Creek Granite and rocks intruded by this granite, and by the zonal arrangement of mineralisation around the Elizabeth Creek Granite" However, not all the rocks
intruded by the Elizabeth Creek Granite are mineralised, the exceptions being the
Kalunsa Granodiorite
Kalunga
iorite and Glen Gordon Volcanics.
Volcanics" Also the Silver Valley
Vallew Conqlor
Conglomerate,
although considered to be older than tfie Elizabeth Creek Granite, is not mineralised.
These unmineralised rocks are presumed to have been impervious to tJre mineralising
Herberton
solutions^ tl
Wolfram/Molybdenum
The principal wolfram/molybdenum deposits were at Bamford and Wolfram Camp,
molybdenite, The
quartz-pipes occurred in greisenized granite close to the contact with the country rocls.
Mining in tJrese occurrences was difficult and costly and the areas are now considered to
be essentially worked out.
where quar&-pipes carried large segregatiors of both wolfram and
The other principal wolfram occurrence in the region is tfrat of
wolfram occurs in quarE-veins.
Mt.
Carbine where
Gold
Principal gold occurrences were quar?-reefs with associated sulphides. This
is
the typical association for most of the Hodgkinson Basin goldfields.
Base
Metals
The Conference will not visit any sites of former base metal activitiesi however,
former copper workings are lmown in the Herberton area (Copper Firing Line).
Minor other base metal occurrences (silver, Iead and zinc) are the lodes in Silver Valley
and the Isabel Mine west of Herberton
some
Alluvial Deposits
Much of the gold production from *re Hodgkinson Basin was from alluvial deposia,
River. Lode deposits were discovered as a result of the alluvial
especially in the Palmer
work.
Significant production of both cassiterite and wolfram is recorded from alluvial
deposia. Alluvial wolfram was produced principally about the }crown wolfram deposits,
Alluvial tin production has been a significant contributor to the value of minerals
production. Two principal types of alluvial deposits are known in the area L.
Recent Alluvials
2.
Deep Lead
15"
I.
Recent Alluvials
The principal areas of production are the stream-courses of Reh-rm, Smiths,
Battle and Nettle Creels. All four of these have been mined by large scale dredging
methods. Two companies are operating in the area, Tableland Tin Dredging N, L. and
Ravenshoe Tin Dredging N. L. Tableland Tin Dredging N. L. commenced operations in
Return Creek in 1939 and transferred to Smiths Creek in 1953 and have recently commenced operations in Upper Reh.un Creek. Ravenshoe Tin Dredging N. L' commenced
operations in 1957 in Battle Creek and subsequently in 1966 transferred their operations
to Nettle Creek.
Most streams draining either tl-re Elizabeth Creek Granite or the contact area have
been worked on a small scale for
2.
alluvial tin.
Deep Lead
The deep leads atHerberton, discovered in 1883, are among the most important
of the alluvial deposits. The leads consist of cassiterite-bearing sands and gravels,
5 to 25 feet thick, overlain by 50 to 1OO feet of basalt, upon an uneven basement of
granite, There are several buried channels over a width of at least half a mile in the
pre-basaltic valleys of the Wild River and its tributaries, mainly bebveen Wondecla and
Kalunga. The leads were worked by means of numerous shafts and a number of adi8,
and values up to 40 Ib. per cubic yard have been reported (Reid, 1932)' A geophysical
investigation by AGGSNA in 1938 suggested the existence of another lead; it was tested
in1942, but the values encountered were unpayable (Cribb, 1946)" Probably more than
4,000 tons of cassiterite concentrate have been won from the leads.
EXPLORATION
IN THE HERBERTON - MT. GARNET DISTRICT*
The Herberton area is one of the most intensely mineralised areas in Australia
and although renowned for its tin mines, there are also significant occurrences of other
metals - W, Cu, Pb, Zn, Ag, Bi, Sb, etc. However, tin is still the focal point of
interest and the bulk of the production comes from two dredges in the Mt. Gamet region
(Tableland Tin and Ravenshoe Tin). The recent mineml boom led to a revival of hard
rock interest and several companies have been actively exploring around the major
mineralisation centres. The majority of the 210OO - 3,000 lmown mines and prospec8
are only small scale operatior$, a factor that has always proved a barrier to large scale
company operations. However, large scale open cut prospects do exist in the greisen
environmenb around the Gurumbah, Coolgarra, Mt, Gibson regions of which several
have been investigated over the last six years. To date, no prospect has emerged with
the right combination of filctors : large tonnage (6, OOO, OOO tods) and suitable grade
() 0.40% Sn). Many of the greisenised areas have been shown to be extensive, but the
tin distribution is usually patchy and has failed to bulk out" Howevet, despite the
initially discouraging results, the prospects of locating significant amounts of low grade
ore have not been exhaustively tested.
On a smaller scale, several companies have worked along the original pioneering
concept of John Moffat of Irvinebank, attempting to establish several small mines around
a central milling operation, This approach is attractive in that, if successfully established,
there are sufficient exploration prospects in the area to maintain the operation for many
years into the future, However, the establishment phase requires both a lengthy and
costly exploration programme aimed at proving around 1rOOO,0OO tons of approximately
1.0% Sn ore, Mining costs on small scale operations are high; detailed and well
By R. G, Taylor, Geology Department, James Cook University of Nortfi Queensland,
TownsVille.
considered_design is essential, and exploration must be constantly active to maintain the
reserves' Loloma Mining Corporation has accepted this challenge and have based tfreir
operations in the Irvinebank/Herberton disbict. After many yeais of constant exploration,
the project has reached the critical testing pointl reserves are established, and a new mili
has been erected on the ou8kirts of Irvinebank near the Jumna Mine. The project will be
watched with critical interest by ttre mining industry, as a similar
could be
"pp"o".h
opper Exploration
fPlliea in any one of tfre remaining tin centres of tle region" Gold-e
is- employing_ a similar altJrough smaller scale philosophy in ttre Sunnymbunt diiuict,
where-a small miII is op_erating upon ore from tfre Tomriry Burns and bther nearby
-in"r"
Great-Northern Mining Corp-oration r-ecently conducted a iimilar style operation 6ased
upon
the Wabonville/Herberton fields and were actively extracting ore in 1970. Unfortuaateiy
the company has faced many financial difficulties and attempts to establish tin reserves '
were abandoned in favour of seeking other base metals,
Another approach often employed in the general area is to attempt to locate one
of the small but very rich tin ore shoo8 which are common in the disbici" Success in
this direction can generate significant and rapid retums. Metals Exploration demonshated
this approach particularly well at the Great Adventure Mine, and ar-e currently operating
in a similar manner witlr tungsten at Wolfram Camp, Barrier Exploration is taking a neil
look at the famous Vulcan Mine which produced 18O"79O tons of ore et an averasE srade
of 4.50% Sn" Other small min_es currently operating include the Greaf Southem [WIfy*",
Irvinebank), the Peacemaker (Petersen Bros", Bakerville), and the Brass Bottle (dreenvale'
Minerals, Irvinebank).
Current interest in other base metals is particularly high, and considerable
attention is being devoted to copper prospec6 in the Featherbed volcanics. Mareeba Min=
ing is exploring the complex of old mines at the United North Australia Leases near
Wa
Wa8onville, and it is interesting to note how a new geological interpretation can alter
exploratiotr thinking. The region has been mined for both tin and copper, but is
particula-rly well trmown for its small but very high grade copper ore shoots, formerly
presumed to occupy normal fissure/replacementleins. It h; now been recognised that
tre copper orebodies are shallow angle replacement lenses situated within r 1o- 3oo
4ippi"g porphyry
dyke" The dyke
has been intensely metasomatised, is mineralised
throughout, and_ is being invesfi-gated for both small"high grade, and large low grade
grade
copper potential.
Lead-zinc-silver prospects are also generating ex.ploration attention, and the
lsobeua
Isobella Mrne
Mine at Herberton is currentty
cunently being drilled by Mareeba Mining" A small but
t
high grade ore reserve has already been established, and prospects for increasing the
reserves are encouraging" Other areas which have recently
recentlv been investigated
investisated include
thePb-Zn-Ag deposits at West Orient and Mt. Albion (Great Northern - Mareeba Mining),
whilst portions of the actensive strike length of the Siberia line of lodes has recently be6n
drilled for its base metal potential (Loloma Mining Corporation).
The high price of tungsten has stimulated considerable activity in tJre tungsten
rich province around Mareeba - Dimbulah : Mt. carbine, resulting in tJre discovery by
of major occurrences of scheelite bearing skarns ifew miles S, E. of '
Mareeba" The extent of the-se is not yet fully established, but the discovery has higgered
a widespread search for similar occurrences. Several lmown wolframite deposits hai6
been re-evaluated, and R.B" Mining have installed new milling facilities atMt, Carbine,
Initial operations will concentrate on the eluvial reserves established around the foot of
the_hill, whilst testing of the adjacent vein occurrences is also underway, The PomPom
wolfram mine near Mt. Molloy has recently been worked by Nickelfields of Australia"
and although production has currently ceased, the established reserves are attracting close
Mareeba Mining
aftention,
t7.
MAREEBA-DIMBULAH IRRIGATION PROJECT*
INTRODUCTION
The Mareeba-Dimulah Irrigation Area is sitrated approximately 40 miles inland
from Cairns and some 11 1OO miles north of Brisbane and comprises lands centred on the
towns of Mareeba and Dimbulah"
Approval to the construction of the Mareeba-Dimbulah Irrigation Project was
given in 1952 and marked an important step in *re development of the northem part of
Queensland.
The scheme originated because of the plight of tobacco growers in the MareebaDimbulah area who needed water supplies for irrigation of their crops and the lmown
suitability of the area for tobacco following 2O years of commercial production, Several
weirs had been built on local sheams thus permitting limited irrigation development in
areas adjacent to these storages, but it was obvious that if increased supplies of water
could be made available for the region a considerable expansion of an already profitable
indusby could be obtained with resultant great benefits to tfie State"
PURPOSE
The Project provides for the conservation of tfie waters of the Barron River by the
construction of a dam at Tinaroo Falls and its reticulation by gravity through a channel
system serving the lands to the east and west of the Barron River and north and soutfr of
the Walsh River.
The scheme allows for the development of some 11 100 farms, varying in size
from 80 to 4OO acres with a gross area of 131, OOO acres. It is anticipated'that 49, OOO
acres will be irrigated annually of which 15,000 acres will be tobacCo,
TINAROO FALLS DAM
Tinaroo Falls Dam, a mass concrete gravity structure, is located on t}le Barron
River about 63 miles from its moutfr (near Cairns) and about flvo miles above the series
of rapids known as Tinaroo Falls. The dam was constructed during the years 1953 to 1958
and was the first large dam to be built in Queensland for the conservation of water for
irr-igation purposes. Its storage capacity of 33O,OOO acre feet is approximately 3/4 of the
volume of Sydney Harbour,
Water stored in tfrdreservoir during high flow in the river will be trcarried overtt
succeeding dry periods of up to six years for disbibution to farms in the area.
The storage filled for the first time on 3lst March, 1963.
__ Th9_dgryr rising 148 feet above river bed level to the abutonents is provided with
a spillway 250 feet long and L2 feet deep for the passage of floods.
Two 5 foot diameter, valve-controlled conduits discharge water to the main
channel, and an additional 5 foot diameter outlet provides for the maintenance of
adequate supplies in the river below the dam,
By the Queensland lrrigation and Water Supply Commission,
20.
2r fee-thigh and g2o feet long, requiring some
of earth and rockfill was built oria low saddle thrle-quarters of a
of the main dam to preventwater escaping through this saddle'Ju"i"j n""ar"
A subsidia-ry e-arthen embankment
^^ ^^^ cubic- y-ards
30.,000
mile south
.
crq"e
and
Thg 9"T-Provides a popular attraction for tourists with its lookout, kiosk, picnic
and facilities fo-r recreation such as power boating, water ski-ing,' sailins.^fishine
swimming.- special a$en{o3 has-been_g-iven to trre Seautification
planting of shade trees, colourful shrubs and-lawns.
""i
tr-r"1.& ild;;
Water is also being released from Tinaroo Falls dam to maintain the hydro-elecbic
generating plant installed for the Northem Electric Authority at Barron Falls near Kuranda-,
but none-tJre-Iess valuable benefit, derived
. A subsidiary,
'gate flood run-off. This was demonstrated duringfrom the dam is its
the flood rains of
:lpagity_!o_:ni
Merch, 1967" The dam at loth March was storing approximitely- 145,000 acre feet of
water. 17 inches of flood rain in the catchment areibn llth March, '1967 caused the
storage to fill and overflow on 15th March.
The_storage of 185r 000 acre feet before the overflow commenced was a significant
.
factor in reducing flooding along the Barron River downstream of the dam, pr.ti""i"r1y----
in the Cairns Area,
Some Facts
about Tinaroo Falls Dam
Capacity
330, OOO acre feet
(90, 0OO million gallons)
Normal annual yield for Irrigation
165, OO0 acre feet
Reservoir area
8, 300 acres
Height of spillway above river bed
136 feet
Spillway width
250 feet
Maximum base width
116 feet
Overall length
1, 750 feet
Quantity of concrete in t}re structure
292,O@ cubic yards
Quantity of e4rth and rock removed to
establish sound foundations
200,
Period of consbuction
1953 to 1958
Actual cost
*$12, 600,00O
OOO
cubic yards
*(Included land resumptions, alterations to roads, railways, telephones
and other
incidental wortrs.
)
-T
nCozparaean
Syorr y hrnsculr,;- TrlrRCo Fnrls
.t
?,
\^,". Flf-,r.,,, DAf,{
r!a
ao
t20,@
90.@
FACTS
Stso9. cop*tt
L.nlth d rott
EOUT TXE OAY
SOOOO Bilbgdbn!
in:;,*m:TI
ro-r.' lllll
I
I
J";iim+
Jil-I
S€CTIONAL ELEVATION OF TINAROO FALLS
DAM
f,EW MAREE€IA
WATEP TWEP
CTI,ANNEL SYSTEM
it is-esti-mated ttrat some 2oO to 2SO miles of
chapels
weerrIj:,1
will
wur *::1"-:"-'j::"tple.ted,
convey water
convev
water by
bY grav-ity from the dam to farms wit$in individual
,""tioo,
of ttre proj ect. ThJ r*t"_aJ
scheme will
wil extend from the dam west
west to
beyond Dimbulah on the Watsr,
'na-e.
"p;;;;
ni.l
;':;;';:..^-,D:L-^L_y+.h
;;"
;djil.=
:f, iil"'TLT:#n
3;11i',?
:l-q:
*""'1 fini'
H;
"d#
y,HJili:';S"*.",
j:*:_111:{_o'."9},i""n#,iJ'o'J,ii"di#.iffi
i,",
u""i ila" iJ,"tr,"';iJl:H.r'l"llST"Xl,.h:1H,:il
I*::l1f,p:.Tl.ti:y,_,io"
:::**
l**lln:+
i:".it1*
fre Walsh River.
weir into the channel
G;;;t"h il;;;;";.J;;'il:T"ffi il#il1,
In certain sections of the project
it is not proposed to serve farms by gravity from
system has been conshucted so as to
povide regulated flows of.irrigstion water in-tfre
naturar watercoursesllliiirl"tJi ilr-"*
wa1.q,e-extelt
has been
and better use made
"i tr,"
**:t*,;1';::a.^1:g::_-",:::t *";h;ii
$f:#i'"v;ilgy:.:lT,j:1"of natural
lljl: sufplies;;;n;bl";;r;;ffi;;;#;:
"r,"oo"Jsystem
23.
t-
where channel supply is available farms will normally be zupplied by gravity'
In some areas farms adjaceni to and above the level of the channels obtain water by
private pumping from the channel system'
In tvyo areas where good quality tobacco soils are located above tfre level of the
main channel system, comirunity pumping systems have been established as part _of the
r-h"-", lifting the water to selected positlons, from whence it can be reticulated to
farms in these areas.
I
!
I
A unique feature of the scheme is that the Barron River waters, which-flow to the
Pacific Ocean, are diverted by gravity in open channel across tfre Great Dividing Ralge
to the Walsh/Mlt.h"U River catihments which flow into the Gulf of Carpenta_ria" This
is possible because at the point of crossing, the level of the Divide is some 30O feet lower
thin the outlets to the irrigation channel at Tinaroo Falls Dam'
1
(
Various types of channels have been useddepending_o:r t}le_terrain and soils.
These include uniined
earth, clay lined earth and concrete lined channels, reinforced
concrete bench flumes and pipelines of precast and cast-in-situ concrete, concrete lined
mild steel and asbestos cement.
The capacity of the main channel leaving the dam is 700 cubic feet per second
ot 3781000,0OO gallons per day.
\
1
To the 30th June, 1967 some 197" 8 miles of channel have been constructed and
total expenditule on tfie icheme including Tinaroo Falls Dam was some $32, 150, OOO"
Where there are available vacant landsrand existing farms are large, the subdivision of the area is being redesigned in conjunction with the provision of the channel
system,
Where required, new gravel zurfaced roads are being constructed to serve the
resubdivision, Upon completion, these roads are handed over to the Local Authority for
fufirre maintenance and improvement.
PRODUCTION FROM
TI{E AREA
Tobacco production has continued as the major form of production from the area"
The proven suitability of the area for high quality Production 9f +t-t crop h19 been-amply
demorstrated. Whil; the recent introduction of the Tobacco Stabilisation Plan will
restict production of this crop in tJre near future to its prese-nt level, further expansion
will inevitably occur as tlre Australian demand for tobacco leaf increases.
The suitability of tlle area for mixed agricultural productionhas also been well
proven. Maize, peanuts and vegetables are but a few of the crops which can be produced.
ln recent years tflere has been a significant increase in plantings of tropical
for seed production purposes and the aree is now reco-gnised-as on-e of
ihe most suitable in AustraliJ for this puipose. Two companies have esteblished facilities
for cleaning and packaging of locally grown seed crops.
grasses and legumes
Experimental work on research stations in tlre area and commercial trials have
cattle fattening on irrigated pashues.
shown highly promising results from beef
I
I
I
I
BEI{EFTTS
OF THE
PROJECT
Durine the vear
lg53,.immediately prior to the construction
:"g"{ 10tJune,
of
Tinaroo Falls"Dam -'
2, 616-;;;r-lr ,ou"..o was pranted, leaf
rotal
from which
'pl",,ti'g,
realised $1,2oo, oob. r" a'""f
v;;;;iJiigioi11,1^",
rgoi,'loil"-"lf
9,200 acres and the leaf sold'i", ,o-"1?i-&Ci,
'
*","
OO6.
The town of Mareeba has deveroped from a population
of 3, 369 in 1954 to
4,813 in 1966, while t}'e population
from 7,59s to
10, 814 over the same
"i-til-sii"".r'MI"""i"]"*e"isea
eetio$. riris rep.esents
an increase or
compared
a
with 28 per Lent for the
+i per-c"rrt for the shire as
*r,oi"-oiA,,ru"f;^;;;; ;h"=;;r=j period.
Local processing
increased from 2o factories in 19s4 to 46 in
1965 with
-industries
total output value of 62,
g37, OOO.
The value of retail bansactions in the-area also
showed a significant increase
from 93,024, ooo during 1es.2-s3
with approxim a tely 3 0 i ew Uw ir,
-s7, s?2,^oo"iFl*- iil;-6, R"ril
cenzus years,
d Jrr-g' Jrt.Uf irf,
"ss"s'
"a.
Additional emol-oyment has been created_for permanent
and seasonal farm
workers and workers iritir6 urtan t""*"-'slrJ""al
to
work during the montlu of November
April each vear coincide with the rl""k ,;g, i",
*g"r;-"";'irrai,,""t work employees
a beneficial effect on t""tott"i-,rrr"tipioy*"rrt
in the Northern part of the state.
and has
TIIE FUTURE
The Mareeba-Dimbulah Area is well served by
research stations which carrv out
vital work on tobacco r:t:tr".r .ropr. - rrr" rilpr.u"ent
primary Industries research
stations at Parada
*.:tuirin a.e activeiy engaged onofprobrems involving
tobacco,
""0 as maize, cotton,
agriculfural crops such
etc. , and irrigated pastures" The Tobacco
Research Instituie on Tinaroo c;";;;;p;.-"i
c. S. I. R. o. is
basic tobacco research.
ry
,
engaged solely on
Research and experimentar work at these stations
has already shown promising
*ilr d.;ttd;;;;#ffi:llir'"
*" prospecrs of
J;;"ioG, n*;il;;;; ;;;;J;'.,
one or the most
results and their continuld operation
the area which, tjroueh not
vet.firuv
successful developme-nts ye t' achievld
i" eu!""*""a,
25.
THE BARRON RIVER HYDRO-ELECTRIC SCHEME*
H
sy
c(
GENERAL
The Barron Gorge Hydro-Electric Power Station was constructed on tfre Barron
River about 12 miles north-west of Caims in North Queensland. It utilises for power
generation the steep descent (approximately 90O feet) of the Barron Falls. The project
is completely independent of an earlier scheme, which came into production in 1935 and
although successful, was too small for present and future needs.
The new scheme consists of a weir with a crest length of 5OO feet and height of
bed, The weir acts as a pondage for regulating flow and diverting
water into the intake, From the intake the water flows into a horizontal tunnel, 5,413
feet long, and an inclined tunnel 1 , 350 feet long. The underground powerhouse has two
generating sets each with a capacity of 30, OOO kW, Regulation of sbeam flow is at
present provided by the Tinaroo Storage of the Mareeba-Dimbulah Irrigation Project,
constructed by the Irrigation and Water Supply Commission on the upper reaches of t}te
25 feet above the river
Barron River,
G
M
II
II
oi
t(
lr
gr
Fr
is
cl
t(
HYDROLOGY
The Barron River drains an area of some 24Osq, miles above Barron Falls, with
a mean average rainfall exceeding 5O inches per annum. It has a long-term average
runoff at the Falls of some 9OO cusecs. However, rain on the catchment falls predominantly in the summer months, with an irregular pattem from year to year. Consequently,
runoff and river flow are exhemely variable, and the firm hydro-power output of the
unregulated Barron River would be very small, For regulation a major storage is
necessary,
Some
2OO
sq" miles of the upper catchment, with a mean average rainfall of
r(
o:
A:.
ar
w
H
n
some-54 inches annually, is now regulated by the Tinaroo Dam,
The hydro-power project was planned on the assumption t}rat the yield from
Tinaroo Dam would be used for irrigation, except for such compensation water as was
required to be released downstream for the original povver station. For tlis, it was
provided that when the flow at Barron Falls fell below 212 cusecs, representing the
maximum demand of the original turbines, water equivalent to the natural flow of the
river at Tinaroo Dam should be released past tlre dam, This natural flow was estimated
at an average 50 cusecs. In practice, some modification of these operating procedures
has been effected to ensure optimum management of the water storage.
The generating capacity of the station is related to the available water and the
load factor on which the station can be efficiently operated. Consideration of these
matte$ during the design stages led to the decision that tfie generating plant should
comprise two 30, OOO kW sets capable of operating at a Ioad factor of about 2r5 per cent.
rThe firm energy outputwas estimated on a conservative basis to be 131 x 10o klAlh
annually. During years of normal rainfall and better, thiq output would be augmented
by non-firm energy estimated to average at least 34 x 10o kWh annually,
E
D
n
e
l
b
e
sr
sl
The original plan for the scheme included a proposal to construct a dam on
Flaggy Creek - one of the tributaries of the Barron. ConsFuction would be timed to
achieve compensation for increasing diversion of Tinaroo water for irrigation purposes"
*
26.
A
u
d
t1
By The Northem Electric Authority of Queensland"
sl
However, subsequent development of the integrated Nortfr Queensland elecbicity supply
q6tem has reduced the significance of any dam on Flaggy creek and proposals ri-u ii- '
construction have been suspended indefinitely.
GEOLOGY
The entire project area lies witlrin the Barron River Metamorphics of Lower to
Middle Paleozoic Aggr_ The_se low grade regional metamorphics comprise mainly
metagreywacke, phyllite, slate, quartzite and greenstone,
The metagreywacke is the most abuadant rock type in the area. Fine and
medium-grained_types predominate" Metamorphism resulted in some recrystallisation
of the mabix with the development of sericite, chlorite and muscovite. The rock is
tough and massive and the joints are widely spaced. The phyllite and slate weather
more readily and break along cleavage planes; where protected by tre more massive
greywacke they are less weathered. A distinctive quartzite forms the head of tJre Barron
Falls and occurs elsewhere inter-bedded wittr phyllite and metagreywacke. The quartite
is- fine-grained and often intensely folded" The greenstone is composed of epidotl,
chlorite and magnetite and has probably been derived from a basiC dyke rock. It is
tough and massive when fresh but gives rise to a greasy clay on weathering,
The regional strike of the Barron River Metamorphics is north-north-west and the
dip is steeply west. _ Jointing is well developed in all rock types. In the vicinity
of the worls faulting on a minor scale is present; displacements are glnerally small scale
re-gional
and the
faul8 now inactive.
Several old landslides are visible around the rim of the gorge. A rock flow Imown
Bluff about 4 miles down tlre railway line from the valve cliamber is due to the
weathering of greenstone to a red clay which, on saturation with moisture, flows"
However, no movemena in the railway line which skirts the edge of the gorge have been
as Red
nobd since
it was constructed.
ENGINEERING WORKS
Diversion Weir
A concrete weir with earth banla was consbucted on the site of a pre-existing
weir. The weir has a maximum storage capacity of tr37O acre feetwith-about 1r 270
acre
feet effective for regulation.
Tunnels and Conduits
The original plans for location of the horizontal tunnel and valve chamber had to
modified when commencement of driving showed ttrat the access tunnel had followed
along a landslide boundary for about 180 feet from the portal" A new location was
subsequently determined 225 feet away"
be
The horizontal tunnel is 9 ft. 6 ins. diam. and 5,413 feet long. Except for a
near the intake and the valve chamber it was excavated without supports.
Aldrough the rock was in general sound, it is believed to be liable to slow deterioration
under the action of water, and t}le hrnnel was concrete-lined tlroughout. In areas where
the country rock is greywacke or quartzite, with adequate cover over the crown of the
tunnel, the lining is unreinforced, but a number of sections with fractured strata and
short distance
shallow cover are reinforced,
27.
F
The penstock is about 1r 350 feet long, inclined at 38o 51t from tfre horizontal.
steel lining of 8 ft. 6 ins. intemal diameter backed with concrete and
subsequendy grouted and designed for partial support from the rock against intemal
pressure. The lining is a simple cylindrical shell without anchors, and relies on the
thickness of the shell and its closely cylindrical form to resist collapse from extemal
pressure when the funnel is drained.
It
has a welded
The surge tank is in decomposed and weathered rock and is reinforced against
full water pressure.
Powerhouse
The underground power station is 145 feet long, 32 feet wide and 87 feet from
the lowest foundation at RL 71 to the crown of the roof excavation. The entire roof araa
was lined with structural concrete for station security and general rigidity at the crane
rails, with a minimum thiclmess of 2 f.t. 0 ins, at the crown and 2 ft, 6 ins, at haunches.
REFERENCES
R., SANDERSON, c.C.,
rrSymposium on Barron Hydro*Electric Project, Part 1
SHEPHERD,8.M., BOYIE, E.F., RUSSO,
General and Civil Engineering Featuresil,
5, 10, September, 1964"
woLFF, K.W.,
ilBarron Falls Hydro-Electric Extension
Case Historyrr, ReportNo,
Queensland, 1966,
I.
E. Aust.,
- Geological
12, Geological Survey of
-
NOUTE LOG
1
FOR SATURDAY 70.6.72
Locality
Mileage
Remarlts
I
2
Edge Hill Council Quatry;
Barron River Metamorphics.
2
10
Hydro Road, Barron Gorge;
Barron River Metamorphics
3
20
Simpson Point; Mareeba Granite and
Barron River Metamorphics,
4
35
Yule Point; Barron River Metamorphics.
5
52
Lyons Lookout; view of topography,
6
73
Molloy to Mareeba Road;
Hodgkinson Formation.
7
105
Gorge Creek; Mareeba Granite.
8
150
Yungaburra.
29.
ROUTE LOG
2
FOR SUNDAY LL.6.72
Locality
9
Remarla
Mileage
3
Atherton Basalt Province;
Mount Quincan
10
t9
Hypipamie Crater
11
35
Ravenshoe; GIen Gordon Volcanics
t2
60
Innot Hot Springs; Elizabeth Creek
Granite; Tin dredging operation
(Ravenshoe Tin).
30.
Herberton; Elizabeth Creek Granite;
13
111
t4
t2t
Two miles west of Atherton;
Walsh Bluff Volcanics"
8
131
Yungaburra,
inspection of tin-mining operation
(Loloma).
ROUTE LOG
3
FOR MONDAY L2.6.72
Iocality
Mileage
Remarks
Crater Lake (Lake Barrine)
15
16
t4
Mareeba granite intrudiag Barron River
Metamorphics.
t7
15
Mareeba granite intruding Barron River
Metamorphics,
18
50
Cairns Airport.
31,
ITINERARY
FRIDAY, 9TH JUNE
5.30
p. m.
P-gp_"rt .Eggle Farm A
8. 15 p. m.
Arrive Caims Airport
8.3O p. m.
Arrive Hides Hotel, Cairns
SATURDAY, 1OTH
irport, Brisbane, by T. A. A.
Flight 462 (light refreshmenrs en rouie)'
JtiNE (Route Log
1)
8.3O a. m.
Depart Hides Hotel, Cairns
9.0O a. m.
Barron River Gorge
12. OO noon
6. @
p.m.
7. 0O p. m.
suNDAY, 11TH
JUNE
8.30 a. m.
Lunch at Yule point
Arrive Lake Eacham Hotel, yungaburra
Social Function (to be arranged)
(Route Log 2)
Depart Yungaburra
11.30 a. m.
Arrive Nettle Creek
12.30 p. m.
Lunch at Nettle Creek (courtesy Ravenshoe Tin
Dredging Limited)
2.30 p. m.
6. @
p.m.
D .C.9
Arrive
H-e-r!9rton_., inspection
areas ( courtesy
_m_ining
l-oloma Mining Corporation N.
t. ) -
Arrive Lake Eacham Hotel, yungabuna.
MONDAY, 12TH JUNE (Route Log 3)
8.30 a. m.
12. 0O noon
Depart Yungaburra
Arrive Caims Airport
1. 1O p" m.
Depart Cairns Airport, by
3.40
Arrive Eagle Farm Airport, Brisbane.
p. m.
T.A.A. D C.
9 Flight 463
55.