Alliston area - Geology Ontario
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PAR COURRIEL :
Mapping was begun and completed during the summer
of 1972 by the authors with the assistance of K. Girard,
H, Lohse, and B. Tittley. Field techniques consisted of
the examination of natural and man-made exposures. Air
photographs at a scale of 1:40,000 were used.
Bedrock Geology: Bedrock is exposed only near Rosemont
in the extreme western part of the Alliston map-area.
Here blue-gray shales and interbedded limestone of the
Georgian Bay Formation and red shales of the overlying
Queenston Formation, both of Upper Ordovician age, are
found in several outcrops (Hewitt 1972; Liberty 1969).
Three other units occur within the map-area but are not
exposed at the surface. These are the Verulam and
Lindsay Formations which are limestones of Middle Ordo
vician age, and gray and black shale of the Whitby
Formation of Upper Ordovician age. Other than the few
outcrops near Rosemont and southwest of Hockley, in the
Alliston area, bedrock is covered by 30 to 140 metres
(100 to 450 feet) of Quaternary sediments (Deane 1950;
Sibul and Choo-Ying 1971).
Division o1 Mines
HONOURABLE LEO BERNIER, Minister of Natural Resources
W. Q, MACNEE, Deputy Minister of Natural Resources
C. A. Jewett. Executive Director. Division of Mines
E. G. Pye, Director, Geological Branch
PRELIMINARY MAP P. 835
Till: All the Quaternary sediments exposed in the
map-area were deposited during or after the Port Bruce
Stadial (Dreimanis and Karrow 1972) of the Late Wiscon
sinan Substage i.e., within the last 15,000 years.
Four till formations constitute the framework of the
exposed stratigraphic succession (Gwyn 1972). Three of
the tills (northern till) were deposited by the south
ward and southwestward flowing Georgian Bay-Lake Simcoe
Lobe, The fourth till unit (southern till) was deposi
ted by a northward flowing segment of the Ontario Lobe.
The Bogarttown Till Is the oldest northern till
(Gwyn 1972, p.145).
It is a pebbly (5 percent), sandy
silt till, dark brown In colour (10 YR 3/3, Munsell).
In its five exposures within the area, it is massive,
very compact,and has a strong vertical joint set. The
unit is 2 to 4 metres (6 to 12 feet) thick and overlies
ice-contact sand and gravel, but it does not occur at
Parts of this publication may be quoted If credit is given to
the Ontario Division of Mines and the material is properly
The Newmarket Till overlies the Bogarttown Till.
It is a sand to silty sand till containing 10 percent
pebbles and is light yellowish brown (2.5Y 6/4).
is usually very compact and massive but develops a
fissile structure after being exposed at the surface.
This is the most prominent till in the map-area, having
been traced from the Niagara Escarpment through the
Newmarket area 65 kilometres (40 miles) east to Lake
Scugog. The unit ranges from 0.5 metre to 12 metres
thick (1.5 to 40 feet), and most commonly overlies
outwash sand and gravel though in four locations it
directly overlies Bogarttown Till. The Newmarket Till
is the 'lower northern till 1 of White (1971). He
concluded that the Newmarket ice built both the Singhampton and Gibraltar Moraines in the Bolton area.
this Is correct, the Newmarket Till is possibly correl
ative with till 'N' of Karrow (1971), which was
tentatively traced to the flank of the Singhampton
Moraine northwest of Dundalk (Cowan 1972, p.149).
Modern alluvium; unsubdivided
Bog deposits; peat, muck, and marl
Windblown deposits; sand and silt
Older alluvium; unsubdivided
The last northern till deposited, the Kettleby
Till, is usually a brown coloured (7.5YR5/2), clayey
silt to silt till containing l percent pebbles.
moderately compact and has a blocky structure. The till
unit ranges from 0.5 metre to 12 metres thick (1.5 to 40
It typically overlies laminated or varved silt
and clayey silt, from which it was derived, although in
several sections the Newmarket Till is directly beneath
it. Evidence was found for two minor advances of
Kettleby ice. Several sections contain a thin (l metre)
unit of varved silts within the Kettleby Till. Kettleby
Till is the 'upper northern till' of White (1971), and
it appears that the Ice advanced up to but did not
override the Oak Ridges Moraine.
Glaciolacustrine beach, bar, and spit; gravel
Glaciolacustrine shallow water; sand
9b Lake Algonquin deposits
9a Schomberg Ponds deposits
Glaciolacustrine deep water; stratified to varved
silt and clay
8b Lake Algonquin deposits
Sa Schomberg Ponds deposits
Glaciofluvial deposits; sand and minor gravel
Glaciofluvial deposits; gravel and minor sand
The last till (southern till) to be deposited by
the Ontario Lobe In the Newmarket map-area Is the Halton
(upper Leaside) Till.
It is silt to sandy silt till
containing 5 percent pebbles, usually moderately compact',
and weathers to a yellowish brown colour ClOYR 5/6), No
direct evidence was found to indicate the age relation
ship between northern and southern tills. However, the ^
relationship suggested by White (1971, p. 217) that the
Halton Till is slightly older than the Kettleby Till
Ice-contact stratified drift; sand and gravel
Kettleby Till; silt to clayey silt till
Halton Till; silt to sandy silt tilla
Newmarket Till; sand to silty sand till
Following the deposition of the Bogarttown Till the
Newmarket ice first advanced to construct the Singhamp
ton Moraine and advanced again to build the Gibraltar
Moraine (White 1971). During the retreat of Newmarket
Ice pro-glacial lakes developed between the ice front
and the drainage divide to the south. This episode was
ended by the advance of Kettleby Ice up to the Oak
Ridges Moraine. However It appears that it did not
override the moraine.
Iqu Queenston Formation
Igb Georgian Bay Formation
The Oak Ridges Moraine is a broad interlobatemoraine complex extending from Schomberg in the Bolton
map-area (White and Karrow 1968) across the southern
part of tne Newmarket area for 140 kilometres (90 miles)
eastward to Colborne. The last ice to override the Oak
Ridges Moraine was the Ontario Lobe during which Halton
Till was deposited up to the crest of the moraine
complex. The maximum extent of this advance is clearly
marked by the Palgrave Moraine (White 1971) which is
composed mainly of Halton Till,
It was developed on the
flank of the Oak Ridges Moraine and forms a part of the,
a. Occurs only in the Newmarket map-area.
b. Occurs only in the Alliston map-area.
Ice-Contact Stratified Drift:
Ice-contact sand and
gravel deposits in the Alliston and Newmarket areas can,
In general, be divided into two categories based on
texture. The first group comprises small deposits
composed mainly of crushable material.
two eskers in the Newmarket area, one east of Ravenshoe
and one west of Blackwater, and scattered small deposits
associated with drumlins, or deposits stratigraphically
underlying till. The second category is typified by
extensive areas of medium-grained to fine-grained silty
sand with only occasional bodies of gravel. These largedeposits are found in the southwestern part of the
Alliston area and the southern half of the Newmarket
area (Uxbridge and Whitchurch Townships). There is
evidence that gravel is concentrated along the northern
edge of the Halton Till sheet and that there is a
general decrease in grain size northward in this deposit
(P.B. Duckworth, University of Toronto, personal commu
nication). This agrees with the general northwest trend
of paleocurrent indicators. In Uxbridge and whitchurch
Townships the deposit has the appearance of an outwash
plain laid down in front of the Palgrave Moraine. The
sand and gravel is directly associated with Halton Till.
However, deformation structures of an ice-contact
nature are ubiquitous in the sediments, and for this
reason they are mapped as ice-contact stratified drift.
Geological boundary (actual or interpreted).
l Small bedrock outcrop.
l Sand or gravel pit.
~^ Glacial fluting in till.
Esker (arrowheads show current direction).
River terrace escarpment or wave-cut bluff.
Three dimensional orientation diagram of long axis of
till pebbles, showing sense of plunge; 100 pebbles
were measured for each diagram.
Unit in which pebble orientation was measured.
The sediments in the southwestern part of the
Alliston area appear to have a somewhat different origin.
There is no discernable trend in the distribution of sand
and gravel bodies. The sediments are mainly fine silty
sand to sandy silt with scattered small gravel bodies.
Further, a knob and kettle topography is well developed.
This is thought to be an area where the ice stagnated,
and ponds formed in which the fine-grained sediments
SOURCES OF INFORMATION
Geology by Q.H.J. Gwyn and S. White and assistants, 1972.
Topography from Map 31 D/4 of the National Topographic Series.
Aerial Photography, National Air Photo Library, Ottawa.
Outwash Sand and Gravel: Outwash sediments are found
throughout the map-area. The largest deposits occur
along the western border of the Alliston area where they
form a pitted outwash plain at 975 feet above sea level.
In several sections they overlie Kettleby Till. It has
since been partially dissected especially northwest of
Everett. The material is predominantly medium-grained
to fine-grained sand with small amounts of pebbly sand.
Gravel is rarely found at the surface, usually occurr
ing under a blanket of silty sand. Other moderate sized
deposits of outwash gravel in the Alliston area occur
north of Sharps Hill, south of Beeton, and south of The
In the Newmarket area, the only economically
important outwash sand and gravel occur in the Oak
Ridges Moraine. The outwash in the valleys north of
the moraine In the Newmarket area is typically silty
sand. Numerous small outwash gravel bodies are associ- ~
ated with drumlins and drumlinoid forms. The origin of
these deposits has been discussed by Deane (1950),
Lacustrine and Beach Deposits: Glac i al lake silt and
silty sand are widespread and most of it was deposited
during the retreat of the Newmarket and Kettleby ice,
The oldest sediments were laid down in ponds, known as
early Schomberg Ponds, formed between the tee margin
and the northern flank of the Oak Ridges Moraine, during
the retreat of Newmarket ice. They have been found up
to 1,000 feet above sea level and a maximum of 90 verves
have been counted. The early Schomberg sediments were
overridden by Kettleby Ice, and upon Its retreat late
Schomberg Ponds formed and massive, laminated, and
varved silts were deposited in the ponds. These sedi
ments range in elevation from 750 feet and 1,150 feet
above sea level.
It is not known whether the glacial
lakes were lowered to the level of Glacial Lake
Algonquin gradually, or in stages. However, no shore
line features were found in the map-areas other than
those associated with Lake Algonquin at 740 feet. At
this elevation well developed beaches, spits, and off
shore bars are present as well as prominent wave-cut
Deposits less than three feet thick are not shown as
Parts of this publication may be quoted if credit is given to
the Ontario Division of Mines. It is recommended that reference
to this map be made in the following form:
Gwyn, Q.H.J., and White, S.
of the Alliston Area, Southern Ontario; Ontario Div.
Mines, Prelim. Map P.835, Geol. Ser. , scale 1:50,000.
Wind-Blown Deposit^: Wind-blown fine-grained sand is
common throughout the map-area. Well developed dunes
are present on the outwash plain in Nottawasaga River
Valley, especially north of Dunns Hill, and on the
lacustrine sand plain west of Baxter in the Alliston
area. Some of the dunes in the Nottawasaga River Valley
were formed before the river had cut down to Its present
level and possibly while Lake Algonquin still existed.
Low dunes and an associated wind-blown fine-grained
sand blankets a large area of the Lake Algonquin plain,
L mile northeast of Alder in the Newmarket area. Thin
sheets of wind-blown sand are present in scattered
areas burying what appear to be well developed recent
Bog and Marsh Deposits:
Peat, marl, and organic rich
silts are important recent deposits in the map-area.
Large areas of the larger bogs have been developed for
market gardening and sod production, especially in the
Alliston map-area. Very few of the bogs exceed 2 to 3
metres in depth, however, a notable exception is the
bog directly west of Husselman Lake in the Newmarket
It lies at the very edge of the Halton Till sheet
and it exceeds 3 metres In depth.
Mineral Resources: The exposed bedrock units have not
been exploited as building materials In the Alliston
area, although the Queenston shale is used by several
brick making firms in the Hamilton-Toronto region.
Because of differences in composition and degree of
weathering, selective quarrying Is possible to obtain
various colouring effects using this bedrock unit
(Guillet 1967). Except for the extreme western part of
the Alliston area, the overlying drift is usually more
than 15 metres thick,
Sand and gravel are the principal mineral resources,
and clearly the most important deposits are in the Oak
Ridges Moraine. Less extensive, but locally important
deposits, occur throughout the area.
In 1970, the
reported production from Uxbridge and Whitchurch
Townships, which straddle the Oak Ridges Moraine, was
just over 5 million tons.
In contrast, the combined
reported production in the other 12 townships, wholly or
partly within the map-area, was 0.8 million to'ns. The
producing deposits are both outwash and ice-contact
stratified drift, and most of the production in the Oak
Ridges Moraine is from deposits buried under Halton
Till, Although there is an enormous amount of granular
material, most of it is silty sand and only a small pro
portion is crushable material. The gravel deposits have
a localized and irregular distribution rather than being
widespread sheetlike bodies. This Implies that consid
erable systematic exploration must be done for coarse
granular material, and that the reserves of such
material are not as great as might be expected in a
landform of this type and proportion. Most of the
exploration work should be concentrated in Uxbridge and
Whitchurch Townships. Regional mapping and airborne
resistivity surveys (Middleton 1971a,b) have been done.
It would now be useful to do detailed mapping followed
by a drilling program.
The following comments can be made concerning
reserves in the parts of the townships within the maparea. Sufficient reserves, for local needs only, were
found in Essa, Georgina, East Gwillimbury, North
Gwillimbury, West Gwilllrnbury, Scott, Tecumseth, and
Tosorontio Townships. Both Adjala and Brock Townships
have sufficient gravel to support small commercial
operations. Only Reach, Uxbridge, and Whitchurch
Townships have sand and gravel supplies to sustain
several large operat ions.
Bedrock Geology and Topography
1972: Paleozoic Geology of Southern Ontario;
Ontario Div. Mines, GR105, L8p. Accom
panied by Map 2254, scale l inch to 16
1969: Paleozoic geology of the Lake Simcoe Area.
Ontario; Geol. Surv. Canada, Memoir 355,
201p. Accompanied by Map 1228A, scale
l inch to 4 miles.
Sibul, U., and Choo-Ying, A.V.
1971: Water Resources of the Upper Nottawasaga
River Drainage Basin; Ontario Water
Resources Commission, Water Resources
Report 3, 128p.
1972: Quaternary geology. Orangeville Area, West
Half, and Palmerston Area, East Half,
Southern Ontario; p. 148-151 ijn Summary of
Field Work, 1972, by the Geological Branch,
edited by V.G. Milne and D.F. Hewitt, Ontario
Div. Mines, MP53, 165p.
Pleistocene Geology of the Lake Simcoe.
District, Ontario; Geol. Surv. Canada,
Memoir 256, 108p. Accompanied by 4 maps.
Dreimanis, A., and Karrow, F.F.
Glacial History in the Great Lakes-St.
Lawrence Region, the Classification of the
Wisconsin(an) Stage, and its Correlatives;
Internat'l. Geol. Congress, 24th Session,
Section 12, p.5-15.
Gwyn, Q ,H.J.
Quaternary Geology of the Alliston1972
Newmarket Area, Southern Ontario; p.144-147
in Summary of Field Work, 1972, by the
Geological Branch, edited by V.G. Milne and
D.F. Hewitt, Ontario Div. Mines, MP53, 165p.
1971: Quaternary Geology of the StratfordConestogo Area, Ontario; Geol. Surv, Canada,
Paper 70-34, lip. Accompanied by 4 maps.
1971: Pleistocene Geology of the Bolton Area
(30M-13), Southern Ontario; Ontario Dept.
Mines and Northern Affairs, OFR5067, 249p.
Accompanied by 2 maps.
White, O.L., and Karrow, P.F.
1968: Pleistocene Geology of the Bolton Area,
Southern Ontario; Ontario Dept. Mines,
Prelim. Map P.477, Geol. Ser., scale
1:50,000. Geology 1962,1963,1964,1965.
Hoffman, D.W., Wicklund, R.E., and Richards, N.R.
Soil Survey of Simcoe County; Rept. No.29
of the Ontario Soil Survey, 109p.
Accompanied by 2 maps.
Olding, A.B., Wicklund, R.E., and Richards, N.R.
Rept. No.23 of the Ontario Soil Survey,
60p. Accompanied by l map.
The Clay Products Industry of Ontario;
Ontario Dept. Mines, IMR22, 206p.
Accompanied by Maps 2130 and 2131, scale
l inch to 16 miles.
Industrial Mineral Resources of the
Markham-Newmarket Area; Ontario Dept.
Mines, IMR24, 41p. Accompanied by Map
2124. scale l Inch to l mile.
1971a: Uxbridge, Whitchurch, and Markham
Townships (parts of), York and Ontario
Counties, Airborne Broadcast-Band
E-Phase R Survey Apparent Resistivity
Contours; Ontario Dept. Mines and Northern
Affairs, Prelim. Map P.725, Geophys. Ser.
scale l inch to 2,640 feet. Survey 1970.'
197lb: Uxbridge, Whitchurch, and Markham
Townships (parts of), York and Ontario
Counties, Airborne VLF E-Phase R Survey
Apparent Resistivity Contours; Ontario
Dept. Mines and Northern Affairs, Prelim
Map P.726, Geophys. Ser., scale l inch to
2,640 feet. Survey 1970.