Map 2339 ORANG EVILLE Paleozoic Geology

ONTARIO DIVISION OF MINES HONOURABLE LEO EERNIER, Minister of Natural Resources DR .l. K REYNOLDS, Deputy Minister ofNaluraI Resources G A Jewett, Executive Director. Division of Mines E, G Pye, Director, Geological Branch

The Niagara Escarpment trends north-south through the extreme eastern part of the map-area though it is largely obscured by relatively thick deposits oi Pleistocene glacial driit. Silurian strata upon the dip Adjniris Map 2340 slope of the Escarpment form the bedrock of most of the area. In the 30°30’ east the glacial deposits overlying the plateau of Silurian strata have M°m’ generated an irregular hummocky topography with relief of 200 to 300 feet. Amount of relief decreases westwards and the physiography of the western half of the map-area is dominated by the drainage system oi the southward ilowing Grand River Older (Ordovician) rocks are exposed only in the northeastern and southeastern corners of the area \ where the Nottawasaga and Credit Ftivers have cut re-entrants into the Escarpment. . 'n;WhiDri.gtoriQ STRATIGRAPHY ‘{ Oueenston Formation (Upper Ordovician-Richmondian) Beds oi this unit are exposed only in the deeply incised river valleys at the eastern i W=t='l°°~imci.en.r edge oi the map-area. The lower boundary of the unit is not exposed ‘Cambridge although outcrops in the Nottawasaga River at Glen Cross may be close to the gradational boundary with the underlying Georgian Bay Forma- tion The lithology of the Oueenston Formation is consistent throughout -Wimdslvck 'BrzritIord M 2343 Niagara F"a 5 the area Dark red, hematitic.blocky, non-iissile calcareous shale seams "' Map 234 up to B leet in thickness typify the formation; thin to medium beds of . grey, sublithographic, argillaceous limestone occur, periodically, inter- bedded with the shales. Grey-green reduction zones subparallel or transverse to bedding are common. In the southeast, between Cataract Belfountain, a minimum thickness of 150 feet of Oueenston shale and ‘ may be inferred along the valley of the northern arm oi the Credit Ftiver. eo° lnthe extreme northeastern cornerofthe map-area aminimum thickness 1 Inchto 50 miles oi 300 feet of Oueenston shale may be interred between exposures Scale at Glen Cross and the upper boundary of the formation exposed in the eastern head of the valley of the Nottawasaga River. Cataract Group (Lower Silurian-Alexandrian) Whirlpool Formation The Whirlpool Formation is exposed only in the southeastern and northeastern corners ofthemap-area. lnthe southeast it is exposed in the valley heads of the northern and southern tributaries oi the Credit River which has incised a narrow embayment into the Escarpment Similarly, in the northeastern part of the map-area, the LEGEND Nottawasaga River and its tributary have cut deeply incised valleys westward into the Escarpment The resistant sandstone beds produce a series of step like falls where crossed by the stream courses. A PALEOZOIC complete section through the unit is exposed at Cataract on the northern arm of the Credit River and again on the northern tributary of the SILURIAN Nottawasaga River where accessible, the sandstone has been exten- SALINA FORMATION)‘ sively quarried, none of the quarries being currently in use. The lower contact of the unit with the Oueenston Formation is sharp and erosional in nature I II 9 Argillaceous dolostone, evaporites. The Whirlpool Formation is typically a very tine-grained, light to medium grey coloured, tan weathering, calcareous sandstone; ouartz GUELPH FORMATION grains are subrounded to well rounded and well sorted. Bedding is thick to massive often with very thin grey-green argillaceous partings. Sedimentary structures are abundant and include a very fine planar 8 Brown or tan dolostone. sedimentary lamination. large and small scale cross lamination, sym- metrical, asymmetrical, and lunate ripple forms, and well developed parting lineation which produces a tabular to platy fracture oi massive AMABEL FORMATION beds.Towards the top of the formation sandstone beds become thinner 7a Eramosa Membern‘dark brown or with a proportionate increase in the amount oi interbedded shale There 7 black bituminous dolostone. is little change in lithology between the northern and southern areas 7 Unsubdivided: grey or blue-grey of outcrop. At Cataract the sandstone has a thickness oi l6 leet, dolostone. in the Nottawasaga tributary section a thickness oi almost 23 feet is exposed. FOSSIL HILL FORMATION Manitoulin Formation This unit everywhere overlies the Whirlpool For- medium mation with a sharp but conformable contact. it is well exposed in stream 6a Mott/ed grey or brown, to coarsely crystalline dolostone, sections and by quarrying activity for the Whirlpool Formation The formation is composed of thin- to medium-. irregularly bedded, medium to dark grey coloured, brown weathering dolostone and dolomitic lime- REYNALES FORMATION)‘ stone. These are finely crystalline with a high argillaceous content The beds are separated by thin, irregular, dark grey shale panings Pale 6b Brown.iinely crystalline to sublitho- weathering chert nodules are common, particularly in the lower beds graphic dolostone. oi the formation, increasing in abundance tothe north oithe area. Rellct textures indicate that the beds were originally bioclastic in nature with CATARACT GROUP an abundance of crinoid material. In the Cataract to Eiellounlain region CABOT HEAD FORMATION the formation has a minimum thickness of 18 feet. A full thickness of 43"55’ almost 27 ieet is exposed in the Nottawasaga tributary section. 6c Moll/ed green and red shale. Cabot Head Formation The recessive weathering nature of this forma- tion has produced a gently sloping bench below the main escarpment The unit is poorly exposed in the map-area and outcrops are restricted MANITOULIN FORMATION to the steep sided valleys of the northern branch oi the Credit River and Nottawasaga tributary. The unit consists ofa relatively thick succes- Ed Grey or mottled brown, fine to me- sion oi light grey to light blue, slightly calcareous clay shale which is dium crystalline dolostone. lissile when dry but plastic when wet. Subsidiary hard beds of light grey. very finely crystalline, highly argillaceous limestone, siltstone and calcareous shale, occur throughout the succession. Strata possibly WHIRLPOOL FORMATION equivalent to the Grimsby Formation of the Niagara Peninsula occur towards the top of the iormation. These beds oi finely crystalline, dark 5e White or fan quartz sandstone. red hematitic, bioclastic limestone and shale, occur interbedded with normal Cabot Head shale over a thickness oi approximately l0 feet DISCONFORMITY—UNCONFORM|TY at Cataract and in the Nottawasagatributary section The lower contact ORDOVICIAN oi the Cabot Head is gradational, being placed at the level at which shale dominates over interbedded limestones and dolostones. A mini- QUEENSTON FORMATION mum thickness oi 35 feet of the formation is exposed in the section at Cataract In the Nottawasaga tributary section Cabot Head beds ‘ 5 Redshale. outcrop intermittently over a thickness of 50 feet. ’

Fossil Hill Formation (’?Fleynales Formation and Lions Head Member GEORGIAN BAY FORMATION)‘ eouivalents) (Middle Silurian-Niagaran) The upper part of the Reynales Formation of the Niagara Peninsula is represented in the southeast part 4 Grey-green and grey-b/us shale, ‘ ot the map-area by several ieet of strata overlying the Fossil HIIIForma- siltstone, limestone. tion Atthis Iatitudethe beds oithe Fleynales Formation have a character intermediate with the Lions Head Member oi the Amabel Formation of Bolton (1953, 1957).The Nottawasagatributary section inthe northeast- WHITBY FORMATION1" ern corner oi the map-area exposes a thickness of almost 2 feet of strata oi this transitional lithology overlying the Fossil Hill Formation 3 3 Grey-brown and black shale. Farther south, in the Brampton area (Map 2337) near Georgetown (Teliord, Bond and Liberty), the Fossil Hill and Fteynales-Lions Head transitional facies appear to be represented by strata of the lower and E LINDSAY FORMATION)‘ upper parts oi the Reynales Formation respectively. However, additional n. is to these g 2 Grey sub//(hographic limestone, ml- detailed stratigraphic work required confirm relationships. 2 As the map scale is limited the Fossil Hill Formation is mapped as a E nor dolostone. unit with the Cataract Group E In the map-area the Fossil Hill Formation is characteristically a brown 2 VERULAM FORMATION)‘ weathering, thin- to medium- irregularly bedded, fine to medium crys- talline, bull to tan coloured dolostone. The beds are separated by 1 1 Grey limestone, minor shale. extremely thin, irregular shale partings The association of pentamerid brachiopods with halysitid, iavositid and syringoporid corals is typical oi the formation. The upper Fieynales-Lions Head transitional facies is composed of regularly bedded, white to tan weathering light grey not occur in map area. colouredextremelytinelycrystallinetosublithographicdolostone Shale fDoes content of the beds is reduced in the north of the area and the formation is lighter in colour The full thickness oi the Fossil Hill Formation (6.5 feet)and Fleynales- Lions Head strata 0.9 feet) is exposed at Cannings Falls on the Not- tawasaga River The contact oi the Fossil Hill Formation with the un- derlying Cabot Head Formation is also exposed at this locality and is sharp and conformable. Minimum thicknesses of 3.5 feet of Fossil Hill and 2.5 feet of upper Reynales are exposed in road cuts on the disused part oi Highway 24 where it crosses the Credit River north of Cataract. The contact between the units is sharp but conformable Amabel Formation (Middle Silurian-Niagaran) Bolton (i953, i957) has subdivided the Amabel Formation of the Bruce Peninsulaintothe Lions SYMBOLS Head, Colpoy Bay, Wiarton and Eramosa Members Subdivision of the Amabel into these members has not been possible in this map-area.The County or Regional Municipality boun- possible occurrence of the Lions Head Member was noted above, and dary. included with the Fossil Hill Formation as strata possibly equivalent to the Fieynales Formation of the Niagara Peninsula Lithology of the Amabel dolostones in the map-area is comparable Geographic township boundary. in part to both the Gasport Member of the Lockport Formation of the Niagara Peninsula and to the Colpoy Bay and Wiarton Members of the Amabel Formation on the Bruce Peninsula The formation is typically Topographic contours. massive. unbedded, light grey to brown weathering, finely crystalline dolostone Beds show considerable variation in texture crystallinity and pOrOSlIy resulting from sedimentary banding and coarseness variation >< Bedrock outcrop. in primary bioclastic material Crinoid debris is the most abundant bio- 43°50’ clastic constituent Colour banding from blue-grey to light grey, fre- quently pink, is common, porosity lS variable and may be intergranular ~ Geological boundary. observed. or vuggy, developed on molds of lossil material. Lenticular reefoid bodies, 5 to 6 feet in height and formed of dense, sublithographic, blue dolostone occur interbedded within the more typical bioclastic Geological boundary, position approxi- dolostones The full thickness oi the iormation is nowhere exposed in IT. mate. the area. A minimum thickness of 49 feet is exposed in the disused “Alabastite" ouarry 1.3 miles northeast oi Alton. The contact with the Geological boundary, position inlet- I ,, _,. ,, underlying Reynales-Lions Head strata is everywhere sharp, welded pre-led. and erosional in nature The upper contact of the formation is not exposed. Ouarry. Guelph Formation (MiddleSilurian-Niagaran) Much oithe map-area west oi the Escarpment is underlain by the Guelph Formation though the unit is mostly concealed by thick deposits of Pleistocene glacial drift (Cowan and Sharpe, 1973). Good exposures occur only along the valley of the Grand River between Belwood and Colbeck. Upper and lower contacts of the unit are not exposed and, because of the sparseness For other conventional signs referto 1.'50,000 National Topographic of outcrop, no reliable estimate oi thickness can be made The unit Map System. consists of medium to massive bedded, unitormlytextured, light brown, fine to medium crystalline, sucrosic dolostone As evidenced by doming of strata at some localities, small biohermal bodies are present within the unit However. poor exposure prevented determination of their lithology and fossil content ECONOMIC GEOLOGY Extraction of Whirlpool sandstone and Amabel dolostone was carried out the late in nineteenth and early twentieth centuries but no quarries REFERENCES are operating at present in the Orangevllle area Much of the region is unsuitable for quarrying because of the thick glacial deposits overlying the bedrock Some areas of thin overburden occur the Grand River Bolton, T.E., 1953: Silurian Formations of the Niagara in (Preliminary (556, valley and could be exploited ifnecessary. The Guelph Formation which Escarpment in Ontario Account); Paper 53-23, 19p, occurs in this region has been used extensively in other parts ofsouthern Ontario (Hewitt and Vos, i972). Bo/ton, T.E., 1957: Silurian Stratigraphy and Palaeon- tology of the Niagara Escarpment in Ontario; GSC, Mem. 289, 145p. Cowan, WR. and Sharpe, D.R., 1973: Map 2326 Oua- ternary Geology of Orangeville; Ontario Division of Mines, scale 1:50.000, Geology 1971, 1972. Hewitt, D.F, and Vos, M.A..1972: The Limestone ln- dustries ol Ontario; Ontario Division of Mines, IMR 39, 79p. Accompanied by Map 2264, scale 1 inch to 15 miles. Telford, P.G., Bond, LJ. and Liberty B.A., 1975: Map 2337 Paleozoic Geology ofBrampton; Ontario Division of Mines, scale 1:50.000, Geology 1972, 1973.

SOURCES OF INFORMATION

Original map by E‘.A.Liberty. Geology 0/ Orangeville East mapvsheet by N. Bond, 1972. Geology of Orangeville West map-sheet by P.G. Tel- /ord, 1973. Preliminary Map, P.947. Paleozoic Geology 0/ the Orangeville Area, scale 1.'50,000, issued 1974, Cartography by C.A. Love and assistants, Ontario Ministry ofNatural Resources, 1975. WW _ 30°30’ 80°15’ Topography fromMap 40F /160/ the National Topo-

V I ~ « i h’Sl.’° ‘ "'3" ’”’” A %irtr!~r.é._t..INGT£‘)N I FSGUNTV AdioinsM=n?34? , Magnetic declination in the area was approximately 8° West in 1970.

Published 1975

Map 2339 Paleozoic Geology ORAN GEVI LLE SOUTHERN ONTARIO

Scale 1:50,000

Metres 1000 0 1 2 3 4 5 6 7 Kilometres i H H H l-I H *1 H i—- I

I i—i l—.L l—t IE I Chains 80 40 0 1 2 3 Miles >§ o ‘Pomsi?, Q‘n. /2