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Ministry of Hon- Alan w.©Pbpe Minister . . - Natural , ,. D 0. . . - ;. John R. Sloan - - ; MARGINAL NOTES ReSOLirGeS© Deputy Minister -. -J Ontario ; , ,. v . ,, , ^ .*-,-...^.- . ''i Paleozoic rocks in Ontario are concentrated into 2 major areas, Ihe southern region which includes strata of the Michigan and Appalachian Basins, and the Hudson Platform in the north Inevitably one of the major endeavours of geologists .investigating these areas is Ihe correlation of : . ;"; ONTARIOCIEOLOGICALSUBVEY .-' - :-; - units between basins (for example Sanford and Norris 1973) Thus, the -:/---!/:© .-; ©-" ,- © MAPP.2700 '\\ - •••'•'" :.;-'- stratigraphy of the outliers of Paleozoic rocks which occur ri fault blocks ac©oss the Precambrian Shield is ot some importance These outliers are , : .' '" : -^ GEOLOGICAL SERIES - PRELIMINARY MAP .) , concentrated along Hie Ottawa Valley and associated structures (see Lumbers 1980) and are shown on the map in Figure 1. The Lake Timis l ©©©:: p\LKOZOK 4 GEOLOGY ;;^-;. kaming outlier is the most important because of its position almost equi distant between the 2 main depositional areas, and because it is the only 'f ---I ''t i - J- " J"© outlier which contains Silurian strata. -f'-'l^h^ LAKE TIMISKAMING PHYSIOGRAPHY " * The topographic depression in which the Wabi and Blanche Rivers flow, and which is occupied by Lake Timiskaming, is the dominant physio V graphic feature of Ihe area This feature was termed the Lake Timiskam ing Rift Valley by Lovell and Caine (1970) and marks the most northerly extent of the Ottawa Valley structural feature and drainage concentra ;-©V--V" Scale 1:50 000 .-©v^- - :'- \ tion. Within the depression, the major feature is an east-facing escarp ment, which runs parallel to the valley sides formed by Silu-r-an rocks. In l Mile the river valleys to the west and east of this escarpment, and burying it in the extreme northwestern part of the outlier, is extremely thicK overbur den containing a large proportion of varved c©ays. Deeply incized valieys in the clays provide the only outcrops in the northern area: lineaments "© NTS©References© 31 M/5 12, 13 . -- defined by stream orientation in this area were assumed by Lovell (1977) to reflect faulting in the bedrock In the southerly part of !he oullier, out V © : " -;" ODM-GSC Aeromagnetic Maps: 1492G, 1493G; 1494G --, crop of Silurian rock is sporadic, but locally extensive, especially on -;v/"©.© ODM/OG-S Geological Compilation Maps; 2205. 2361 .y Dawson Point. Ordovician strata are exposed extensively only in 2 areas west of Hailebury and Cobalt, soulh and west of the main valley, but an isolalec Ordovician outcrop occurs on Highway 65 on the flanks of Ca SGovernmenl of Ontario 1984 sey Mountain, a Precambrian knob which protrudes tnrough Paleozoic cover. Parts of this publication may be quoted if credit is given and the material The distribution of bedrocK outcrop areas is shown on the Quaternary is properly referenced : ,, .© ,:- i - -©-.-, ,t ;V/ ; - ..^ t-./ . geology maps of the New Liskeard and areas (Morton ei al 1979: King and Morton 1979) Morion et al (1979) showed locations of This map is published with the permission of V.©G. Milne Director On sinkholes which developed in overburden matena© in response to karstic tario Geological Survey. - -. - - ;. .;; : ; . . "- . features in the underlying bedrock (lor example, widened joints) Re gional engineering conditions for the area are shown on the Engineering Geology Terrain Sludy maps by Roed and Hallett (1979a. 1979b) PREVIOUS WORK The significance of the Paleozoic rocks in the area to the interpretation of -^v.^ , i .. , the geological history of a large section of North America has long been recognized (Hume 1925: see also references included therein) Hume (1925) proposed a correlation of the topmost Silurian units rn the area to the l.ockporl Formation of southern Ontario; that the Middle Ordovician sequence of basal sandstones and siltstones overlain successively first by shales then a thick limestone unit, be termed the Liskeard Formation, and that the lower part of the Silurian sequence of "shaies and limestones" be called the Wabi Formation. Hume considered that a fur ther shaly formation, of Upper Ordovician age, should be present but was not exposed. T^e lower contact of the Lockport with the Wabi For mation was marked by a sandstone bed overlying a "slight disconformity" Hume identified wide marine connections to Ihe north CREEK ana south during both Ordovician and Silurian times, from fossil content. ONTARIO OUTLIERS Subsequently work on Ihe fauna of the exposed strata was continued by Oiierenshaw arid MacQueen (1960). who first used the term Thorntoe Formation instead of ^ockport as suggested by Flower (1946). since the 1-Lak* Timitkaming strata in question were demonstrably older than the Lockport of southern Ontario and New York 2-Manitou Islands The first detailed maps of the area were by Thomson (1956. 1965) Thomson (1965) first reported the drilling o* an important borehole refer- 3-Restoule red to as LT-1, from the lake ice off Dawson Point m 1963 (PC 042595), Scale: 1:1 584 000 or 1 inch to.25 miles which intersected the bulk ot the Paleozoic sequence The most signifi 4- Oeux Rivieres cant observation was of abou! 30 m of green, grey and reddish © ^ w ©l p© shale ^yMKT^ ©© above the thick Ordovician limestones, thereby substantiating the pre diction of Hume (1925) Sinclair (1965) elevated the Liskeard Formation Bl^WHAMl©TP y y^ 5-Brent Crater X Cedar Lake to group status based on the sequence in LT-1, and named 4 formations .-;: y .- : ,. 6-Renfrew County within it: 47 t. Liskeard Oroup - " ~" LEGEND Dawson Point Formation soft grey-green shales© Farr Formation limestone PALEOZOIC © Bucke Formation shales with thin limy layers - H , MIDDLE SILURIAN Guigues Formation sands, sandstone, conglomerate Thornloe Formation; med©um to thick bedded, fine to The Dawson Point Formation was, therefore only known from its pres FIGURE 1 medium crystalline dolostone and. cherty dolostone ence in LT-1. The age of these formations ranged from Late Wilderness with some thin bedded limestone ,- (Guigues and Bucke) through Late Barneveld (Farr) to Edenian (Dawson " f ' - V Point). Earlton Formation© thin bedded very finely crystalline Munro (1975) analyzed the conodont biostratigraphy of the Ordovician to sublithographic limestone with colour-lam i naled do units, and showed that there was a reworked zone of ruobiy limestone lostone in lower part . " -; •'\ .*. --. -; -.-. ©,- r - with a FaT conodont fauna between tie massive mottled limestone of the Farr Formation and the shales of the Bucke Formation. The Farr Forma cXv© -r--/ LOWER-MIDDLE SILURIAN tion, and therefore, the overlying Dawson Point Formation, were also WABI GROUP -. . , shown to be somewhat younger (Edenian to Maysvillian) than previously proposed. Evanturel Creek© Formation:© green to grey mjdstone and shale with grey anc blue mottled finely to medium Poole el a! (1971) raised Ihe Wabi Formation to group status, based on crystalline dolostone -©vJ; "'"-'- ' -© © "- © observations of LT-1 (B.V Sanford Geological Survey ot Canada, per sonal communication. 1983) containing lithoiogical equivalents of the Cabot Head-Formation- red and green mudstone with formations making up Ihe Cataract Group of the Bruce Peninsula m fibrous-gypsum southern Ontario The Thornloe Formalion was recognized as the upper 196 feet (59.7 m) of the borehole as opposed lo Thomson (1965) who Manitoulin-Formation© dark grey and buff, very finely to followed the definition of Hume (1925) and assigned oniy the upper 97 ©finely crystalline dolostone and limestone with shaly feet (29.6 mi) to that formation. Poole et at (1971) correlated the Thornloe partings Formation as so defined to the Fossil hill Formation of southern Ontario. .''•-.-.'••'..'•••DISCONFORMITY : ©.;--" -V Y©. : - © ; -1 .© Extensive study of the Silurian fauna was synthesized by Bolton and Copeland (1972). In summary, they concluded that ©the stratigraphic MIDDLE-UPPER ORDOVICIAN.© " ,© r --;- -1 ©.© .;: © '' ?\ . and faunal sequences©iare a duplication of the Manitoulin Island Silurian LISKEARDGRQU.P - " . '[' '-.: .;:Vy . - -- ©. © to the south © (Bolton and Copeland 1972, p.10), and suggested several lithoiogical equivalencies between strata of Manitoulin Island and of the 1a* Dawson Poinl Formation: blue-grey, olive green, study area The mosl recent work on the area was by Colville and John and red calcareous and non-calcareous shale son (1982), who identified 3 pentamerid-bearing units and correlaled ib-.Farr Formation medium to thick bedded, bur- them with similar beds on Manitoulin Island and the Bruce Peninsula. : . rowed calcarenitrc and-dolomitic limestone The marked alignment of structural features parallel to the trend of the 1c- Bucke Formation: interbedded blue grey fissile outlier was pointed out by Lovell and Caine (1970). Further major photo lineaments were also identified by Lovell and Frey (1976). and Lovell - shale and shafy nodular limestone (1977) The major fault system bounding the outlier on the western ex Id Guigues Formation, poorly sorted red sandstone tends many kilometres along the western shore ot Lake Timiskaming ^. and conglomerate . -".: .. .- ©.--. : -. Kumarapeli and Sauli (1966) and Lumbers (1980) considered the Lake Timiskaming structural zone to be a northern branch of the major 01- UNCONFORMITY'- -:jV" --- --. -;";. ©©-. " tawa-Bonnechere rift system

PALEOZOIC STRATIGRAPHY Undifferentiated igneous and metamorphic rocks Several revisions to previously used stratigraphic divisions and terminol ogy have become necessary after detailed logging of LT 1 (now stored at the Atlantic Geoscience Centre, Dartmouth. Nova Scotia), and the "Indicates units wriich occur m the map areaonly in the subsurface section on the eastern side of Dawson Point (PC 071622; see Figure 2). Although the divisions of the Liskeard Group proposed by Sinclair (1965) from LT-1 are broadly apolicable. the exact -location of contacts in LT-1 require discussion. The disused quarry ("Shipyards Quarry" of Hume 1925) in lot 10, concession V of Bucke Township (PC 013582), is said by Sinclair to expose the upper part of the Bucke Formation and the lower beds of the Farr Formation. However, this sequence resembles the sec tion between 1800 and 189.1 m depth in LT-1, rather than at 202.5 m i 1 -© r 'r J*T \ r©\ which is the location ot the Bucke-Farr contact in LT-1 given by Sinclair. ^ \ "A After reloggmg 202 5 m m LT-1 was relogged to be in the middle of a downward transit©on from calcareous shale to non-calcareous siltstone. •-t.—V^^—^ The base of the Farr Formation is therefore, placed at 1860 m in LT-1; neither in Ihe core or in exposed sections were suggestions of a discon SYMBOLS formity noted The base of the Bucke Formation is not exposed, but is reported at a Bedrock outcrop . , :: .. depth of 226.6 m in LT-1 by Sinclair (1965) However from 2108 m *--. f© .? . down, there is a significant proportion of red and green siltstone and .--••! -t..rf :; Quarry "© - . © . ! ^ ^ ; sandy siltstone, which would best be differentiated from the shaly lime stones and shale of the Bucke Formation and placed in the oasal Gui ©Geological boundary,.© ©" gues *©o©mation. The contact between the Bucke and Guigues Forma position observed © - tions is, therefore, placed at 210.8 m in LT-1. Subdivisions of Silurian strata used herein differ somewhat from those Geologtcaf boundary^ .i. outlined by Poole e! al (1971). Based on the LT-1 section, the Wabi For position approximate . ."; mation is restricted to the strata from 70.8 to 114 8 m depth, but is raised to group status The Wabi Group can be subaivided into units of forma Geological boundary; ..-. tion rank lithologicaty equivalent to the Manitoulin and Cabot Head For position assvimed - . ; mations of southern Ontario, and a third formation having some attrib utes of both the Wingfield and Dyer Bay Formations. Rather than impose Fault, position ,.© either of these names on a unit which contains strata which would not be approximate (arrow .- 4 included m tnat formation in southern Ontario, this unit is named the indicates downthrowrt/©© Evanturel Creek Formation, after Ihe creek south of englehart where it is well exposed. side) ©-- -F - - ^ : t- ;*. Above the redefined Wabi Group (70.8 m in LT-1). lie limestones and do- Linear scarp feature© /© X. lostones previously assigned to the upper part of the original Wabi For- mat©On and to the Thornloe Formation. The upper part of the Wabi corma- tion. in previous usage, has roughly equal proportions of limestone and Location of cfiatoond-. -'t "drill-hole - ©.© © - -I dolostone. On the eastern side of the Dawson Pcxnt peninsula, which is the type section for the upper part of the Silurian section a significant thickness ot thin-bedded, very finely crystalline to sublithographic lime stone with shaly layers, and bioclastic ana ooMic beds occur oeneath the sandstone bed marking the base of the original Thornloe Formation. MOUNTAIN These carbonate lithologies are characteristic of the lower 25 m of the © original Thornloe Formation At locations such as the Silurian escaip- ment west o! Casey Mountain, tne sandstone bed is absent Irom the sec tion exposing the old Wabi-Thornloe contact. The use of the sandstone bed, or equivalent horizons, as a contact between units is. therefore, dis continued. The most distinct change in lithologies in the Dawson Pomt section is at 36 4 m above lake level, where the thin bedded limestones with some dolostones are overlain by massive resistant doiostones, to which Flower (1946} was referring when suggesting Thornloe as the for- mational name Based on these observalions, the Silurian section above the Wabi Group is divided into 2 formations, a lower newly defined Earlton Formation, and an upper redefined Thornioe Formation The Earlton Formation is V \P .i l; named from Ihe town of Earlton, north of which a quarry (NIC 884884) V ©" [© . STRUCTURAL GEOLOGY ,- , ; \ m Mi 'Nit Tt '-I * ' provides good exposures of the unit. The formation extends from 70 8 m BOREHOLE LT-1 - ., The western edge o-f the Lake Timiskaming DU t Her is formed by 2 ndrth- depth up to 8 7 m in LT-1. The base ot the Earlton Formation is not expo wesferiy trending normal faults with a cumulative downthrow of at least© sed on the Dawson Point section, but the upper contact is exposed at 240 m (Hume 1925; Lovell©and Came 1970). tf post-faulting erosion of 36.4 m above lake level The Thornloe Formation includes the top 05m Precambrian is.significant, then the downthrow may exceed this figure cored in LT-1 and the over 35 m of rock above 36.4 m in the Dawson ©. The eastern edge of the outlier is poorly defined,- but a fault zone follow Point section. - ing the Blanche River was postulated by Lovell and Caine (1971) and Lo- ; ©: veil (1977), presumably Unking with the fault. W©th downthrow to the east: Liskeard Group (Middle-Upper Ordovician) -, © on the eastern side of Casey Mountain mentioned by Thomson (1965) Rocks of the Liskeard Group are exposed in 2 fault blocks south of the Thin bedded, very fine to l - Lovell and Came (1971) showed Paleozoic sediments to be present east .-of this fault main outlier and west of Casey Mountain on Highway 65. Most of these sublithographic grey limestone out thinning rapidly to the east No outcrops of Paleozoic outcrops are of Far Formation, however, so it is not possible to delineate with shaly partings, bioclastic and . t strata are known, east of Blanche River, nor are any water wells reported the extent of the formations within the Liskeard Group on the map. The oolitic beds in upper part; ' .lo intersect (tmeslone or shale/Since the data available is very snarse - ©-i l he configuration of the eastern boundary is extremely tentative How- Guigues Formation is exposed on the shore of Lake Timiskaming near interbedded in lower part with the sawmill north of Hailebury (PC 014584), and is represented by about " -; : ever, this author prefers the concept of a Blanche River Fault Zone with thinly laminated, very fine to ©,; net downthrow to the west, forming a true rift valley analagous to the Ot- 6 rn of poorly sorted red quartz-pebble conglomerates and coarse sublithographic dolostones. grained sandstones The outcrop on the side of Casey Mountain is a © ...© tawa-Bonnechere system. . -- spectacular exposure of large (up to 2 m diameter) rounded quartz :; - © The use of lineaments defined by stream courses (for example. Lovell syenite boulders in a dolomitic matrix unconformably overlying heavily © , 1977)©has been followed in pal m the northerly part of the area to allow weathered quartz syenite in place Since, according to Sinclair (1965) ' . interpretation of the location of the faults bounding the outlier on its west- the upper par! of the Guigues Formalion is carbonate-cemented, this \ \\ . .ern edge A distinct photo lineament, which is evident on the ground as a unit is placed tentatively in the Guigues Formation Hume (1925) and . " distinct west-facing 10 rn scarp, is present m the southern part of the Thomson (1965) have given evidence of significant topography on the ©." area stretching from near Thornloe to Wabi Bay, east of New Liskeard Precambrian floor, so this type of unit will be widespread; the Guigues . -- This feature LS parallel to the regional structural trend, yet-bedrock is over Formation is probably highly diachronous, and its thickness wiH be varia © 40 m deep along its length The most likely cause ol this feature, despite ble. Indeed, Munro (1975) showed that this outcrop was the same age .."- .the extreme straightness, is a bluff formed in Holocene time by a higher as the Farr Formation, In LT-1, the lower 50.7 m is assigned to the Gui - -© .lake level, but tt may also reflect a relatively recent fault in the bedrock. gues Formation. Few fossils are found in the Guigues Formation. Bolton :© t However, the mechanism oy whicrvan extremely straight feature such as and Copeland (1972) reported poorly preserved anthozoans and ce- generally characterised by greenish . ; © this could be propagated through many metres of clay is not obvious. It phalopods ot Wilderness age, a similar age is indicated by the conodont md buff dolostones with thin green :. ©.© may be significant that a magnitude 6 earthquake occurred in 1935 at fauna (Munro 1975). ihale interbeds; many other lithol © \Temiscamingue. Quebec at the southern end ot the Lake Timiskaming )gies present" m©n thint h beds (e.g. .©- ; . structural zone " © - The Bucke Formation is exposed at the "Shipyards Quarry", above the ntraformational conglomerates, sawmill near Haiiebury, and at the New Liskeard dump (NC 967629) At jrecciated red shale in green shale T .1 -M l S K A M l \ G '•'*. , South of New Liskeard, the northwesterly trending faults are intersected both locations it is represented by interbedded blue grey fissile shale natrix). .: © v ©by a northeasterly trending set. which cause the preservation of Ordovh and very shaly nodular limestone, the nodules are very finely crystalline Dolomitic red shale, often --- : cian rocks in the 2 fault blocks west of Hailebury and Cobalt. to sublithographic light g rey limestone and are often entirely enclosed brecciated and interbedded with green shale, greenish-grey ; -©The dip of Paleozoic straia©varies widely according to proximity to faults." by shale The upper contact with the Farr Formation is interbedded and .© -i : " Away from fault zones, the dip is genfle.and slightly variable ranging is sandstone, fibrous and crystalline DAWSON POINT SECTION marked by the first massive bed of burrowed limestone, the upper few gypsum, dolostone at base. ~. -.-" from Oc to 30. with strikes generally to the north or northwest, dipping to metres ol the Bucke Formation contains thin calcareous beds which - the west. The regional dip probably lies between those 2 values, stand out relative to the more shaly lithologies, but still have significant irownish buff, mottled grt-y, very New Liskeard shale content. The Bucke Formation was determined to be 19.7 m thick ine to finely crystalline dolostone vith undulating shale laminae and Predominantly thick bedded ECONOMIC GEOLOGY ; V from the LT-1 borehole The upper parts of the Bucke Formation contain i o m e bioclastic bands: calcarenite dolostone, ranging from very finely numerous DAWSON POINT fossils of tne coral Streptefasma corniculum. Copeland (1965) it base. crystalline to medium crystalline, - ©Numerous disused quarries are present within the Paleozoic carbonate determined from the ostracod fauna that the Bucke Formation was of typically buff or tan, with chert SECTION ; -© rocks of the area, having been exploited for production of lime or con- Late Wilderness age -© struction Mainly grey, olive green slightly nodules in lower part and abundant materials The only quarry active at present is that west of Halle The Farr Formation is widely exposed west of Haiiebury and Cobalt, calcareous shale, with some bury (PC 002568), ooerated by Dvmond Clay Products Limited which is silicified fossils in upper part, , .7 extracting along Highway 17, m used and disused quarries, and at the locations bioclastic, calcarenite bands: thin, pure limestones of the basal part of the Farr Formation for separated by a unit of very thinly agricultural lime Parts of the Thornloe Formation exhibit similar outcrop mentioned above where :! overlies the Bucke Formatton It is character red, shale-bearing unit at top: thin, ized by medium to thick bedded, fine- to medium-grained calcarenites. laminated, very finely crystalline, . © characteristics to the Amabel Formation of Manitoulin Island and south- non-calcareous, blue-grey shale pinkish grey limestone. ,,-.,0.", ern Ontario, with finer grained, more dolomitic lithologies becoming dominant higher 4; au. which is- widely used as a- source of high quality crushed in the unit, and is usually heavily burrowed giving a distinctive mottled at base. ", rock aggregate material. . - . i . ' ~- appearance In the 41.1 m of Farr Formation identified m LT-1. the unit can be subdivided into sections characterized by different types of bur row infill, amount of burrowing and the presence of undulating shaly .-'- REFERENCES ; . .V-.©V©©. © ' ' •'\''1 ' ,* . stringers. More detailed observations of exposures may allow subdivi sion of the Farr Formation in the field based on these criteria The abun Bolton. T E..andCopeland, M J - - .© '- . ;.-- - : dant fauna of the Farr include many corals, Receptacutttes brachiop i©9.72 1 Paleozoic Formations and©Silurian Biostratigraphy, Lake Timiskaming Re As in borehole; od s. and gastropods (see Hume 1925 for faunal list for all Liskeard gion, Ontario and Queoec; Geological Survey of Canada, Paper 72-15, Medium to thick bedded heavily . 49p. © © . © ©. . © ," :. -- © . " - ~-- Group formations). These and the ostracods noted by Copeland (1965) sandstone from 15.2 to 16.0 m. indicate a Late Barneveld age Munro (1975) showed that, s nee the up burrowed fine to medium "".Calville.V fi :©and Johnson, M E .© " - © © per 20 feet (6.1 m) of the Bucke contained a "Farr conodont fauna" asso 1982: Correlation of Sea-Level Curves for the Lower Silurian of the Bruce Pen/n- ciated with well worn forms characteristic of the Bucke Formation, the calcarenite with some shale . suia and Lake Tfmiskammg District (Ontario); Canadian Journal of Earth BOREHOLE - i©- 1 , Sciences, Volume-19, p,96?-974 zone was probably reworked during Ihe initial phases of deposition in laminae, especially in lower part. late Barnevelo time It is recognised that the definition of units used ©. Copeland. M.J. . © - . herein involves a corillict between time-stratigraphic and rock-strati ; ; 1965 Ordovician Ostracoda from Lake Timiskaming. Ontario. Geological Survey graphic contacts. However, the clearest fie©d-observable difference oe- ; - o1Canada.Bultetm127,.52p.- ;^ , - ,- .. . ©. .1: ,. . .. tween Ihe units is the contrast in shale contents and as such is, therefore, -) Flower. R H © " : "-© ;. © © © - : used as the mapping criterion. Munro (1975) also extended the age ot .©.; 1946- Ordovician Ceohalopods ol the Oncinnati Region. Bulletin of American Pa- the Farr Formation to Early Maysvillian } . leontology., Volume 29, Number 116,1ootnotetop.519of volume. The unexposed Dawson Point Formation is only known from the LT-1 bo "©- Hume.G-S. ". .© - - © ; . . -- 1925. The Paleozoic Outlier of lake Timiskaming, Ontario and Quebec; GeolOQh rehole Discontormably overiyng the Farr Formation, there is an intri Thinly interbedded soft fissile cal Survey ol Canada MemOT 145,129p guing similarity in the overall internal sequence between it and the Blue green and blue shale with nodular Mountain-Georgian Bay-Queenston Formation sequences of southern shaly limestone. . ©, King R;C F . ana Morton J D . Ontario The basal part of the unit, predominantly non-calcareous blue . f. 1979 1 Quaternary Geology 6f the Englehart Area, District of Timiskaming; Ontario" and olive-grey shales (Blue Mountain Formation equivalent), is overlain "© .- Geological Survey. Preliminary Map P 2292. Geological Series, scale ; © 1 50000 Geology 1972. 1977-1978 by more calcareous grey and blue shaies with calcarenite and silty bands (Georgian Bay Formation), then by a thin, red shale unit (Queen- i kumarapeli, P S .and©Sayll. V.A. " © ston Formation). The Dawson Point Formation is 27.9 m thick in LT-1 Sin ,. 1966. Tne St Lawrence Valley System a North American Equivalent© of the East clair (1965) noted trilobite and graptolite fragments, whicn indicated an . © African Rift Valley System.: Canadian Journal of Earth Sciences, Volume 3, Edenian age. However, the work of Munro (1975) suggested a younger p.639-658. . . v ; ,; .- . V. . - . © ^ ;.;. © ©Lovell, H.L. ;"- " . \© - -\ -\ '- '-, \ ..© "-©" :©-©© age. '\.--~ f-: -~.-. s /J5 tr . ! 1977: Geology ol !he Engleriart-Eariton Area, District of Timiskaming; Ontario Ge Wabi Group (Lower-Middle Silurian) Red, green and grey ological Survey. Miscellaneous PaperB9. i6p, © - - Although the stratigraphic revisions noted above have resulted in a re non-calcareous siltstones in upper - Lovell. H.L. and Came, T W 1 - 1.970: La"ke Timiskaming duced thickness for this unit, the elevation of the Wabi to group status is Ritt Valley, Ontario Department ol Mines, -Miscellaneous part; fine to medium sandstone in © v " Paper39,16p ©- . - ," .© confirmed since it contains 3 rock units which, were they to outcrop, would be easily rnappable and, therefore, be of formation status Unfor- lower part. ©, Lovell, H.L. and Prey ED . !unately, only the Evanturel Creek Formalion, the topmost unit of the - 1976 Geology of the New Liskeard Area, District of Timiskaming; Ontario Division Wabi Group, is exposed in the field area The outcrops along Evanturel ol Mines. Geoscience Report 144" 34p. © Creek show a sequence ot green and grey ripple-marked and mud- - Lumbers, SB. ©- -.©". ~. ' ' . . - ' 1980: Geological cracked mudstones and shales overlain by medium-bedded buff fine to Setting of Alkalic Roch-Carbon©atite Complexes in Eastern Can- ! " ada. p 81-89 in Proceedings of 1st International Symposium on Carbona- medium crystalline dolostones. occasionally mottled blue-grey and buff .; Wes edited by J.C Brager Pocos De Caldos, Brazil. -. - Farther upstream, oolitic and bioclastic limestones and other lithologies characteristic ol the Earlfon Formattor are present. The base of the Wabi © ©" Morton. J.D. King. R C F, and Kalin. M W © ." " ; © ,© Group (and, therefore, the Silurian strata) is not exposed. In the LT-1 bo 1979 Quaternary Geology of the.New Liskeard Area, District ol Timiskaming. On , .- . .tario Geological Survey rehole, Banded ironstone. Preliminary Map P.2291, Geological Series, scale the basal unit is a distinctive crinoidal calcarenite sharply overly © -::-" :©- -1.50000 Geology 1972. 1977 ing the Upper Ordovician shales. Above this, the similarity of lithoiogical succession between the LT-1 sequence and southern Ontario is striking Munro, l. The red shales of the Cabot Head Formation and mottled dolostones of 1975: Ordovician Conodont Biostratigraphy of the-Lake Timiskaming Paleozoic -]- Outlier. M.Se Thesis., University of Waterloo, 161p © ;"-.©1 . the Manitoulin Formation exist in similar thicknesses to those exposed on FIGURE 2 Manitoulin Island. The Wabi Group is 44.0 m thick in LT-1 The contact Oiierenshaw, N.C . and MacQueen. R W between the Wabi Group (for example, Evanturel Creek Formation) and ",- i960- Ordovician and Silurian ot Lake Timiskaming Area, Proceedings, Geologi- the Earlton Formation is exposed in a small pit at NC 044698 The expo \' cal Association ot Canada. Volume 12 p©105-115 . " . . ; sed strata have a bivalve-ostracod fauna which Bolton and Copeland - Poole, W.H.. Sanford B.V., Williams, H., aid Kelley, D G - - -. - (1972) interpreted as indicating a Middle Llandovery age, and which is . 1971. Southeastern Canada; p 227-304 in Geology and Economic Minerals of common to formations extending from the Yukon to Anticosti Island. Canada, Geological Survey of Canada1, Economic Geology Report Number 1. - - -. © -©.." - " -- •:- Earlton Formation (Middle Silurian) .©. Roed, M.A. and Hallett, D R . - "" © " ©. © . ". © © 1979a Northefri Ontario Engineering Geology terrain Study, Dais Base Map. The Earlton formation is characterized by thin bedded very finely crys New Liskaa.rd; Ontario.Geological Survey, Map 5021, scale J 100000 talline to sublithographic limestones and finely laminated dolostones, -. 19?9b: Northern Ontario Engineering Geology Terrain Study, Data Base Map. with significant interbeds of bioclastic and oolitic limestone The sand : Haileybury, Ontario Geological Survey. Map 5024. scale 1 100000 stone bed. which was previously used to define the base o- the forma " Sanford. B.V., and-Norns, A W . © © tion, is present only at the northern end of the Dawson Point peninsula. j 1973: Hudson Platform, p.397-409 m Fulure Petroleum prcvinces of Canada, edi This bed is approximately 50 m above the base of the newly defined ted by R G McGrossan, Canadian Society of Petroleum Geologists. Earlton Formation The base of the Earlton Formation is defined as the . Sinclair; G W . ' top ot the highest greenish grey dolostone o* the Wabi Group underlying ©, 1965: Succession of Ordovician ROCKS al LaKe Timiskaming, Geological Survey thin bedded limestones and coiour laminated dolostones, and is a: 70 8 of Canada. Paper 65-34, Gp m m LT-1 Dolomilic beds dominate in the lower part of the formation, but significant limestone beds are also present, as shown in the Evanturel ."- Thomson R. . . © © ©- 1956: Township of Bucke District of Timiskaming; Ontario Department of Mines, Creek section (see above) The Earlton Formation is exposed extensively Map No 1956a©scale 1 inch to©A mite. . in the clift section on the eastern side and at the tip of Dawson Point, but olher outcrops are soarse it is not exposed between New Liskeard and - - 1S65: Casey and Harris Townships; Ontario Department of Wines, Geological"Re- the quarry northeast of Earlton. Mapped contacts between it and the un . port 36 77p derlying Wabi Format/on are largely interpretive, based on Ihe few out crops and bedrock topography contours In the LT-1 borehole, the Earl ton Formation is 62.1 m thick; over 35 1 m of Ihe formation are exposed : ;! SOURCES OF INFORMATION on the eastern side of the Dawson Point peninsula Hume (1925) and Bolton and Copeland (1972) gave comprehensive faunal-lists for the . -Topography from Maps.31 M/5. 31 M/12, and 31 M/1-3 Of the National To original Thornloe Formation; for thr; lower part of the formation (now the pographic Series Earlton Formation), these inciudeu many corals, gastropods, and bra- . Water well records of the Ontario Ministry of the Environment. chiopods. notably Pentemerussp, which is common in the abundant thin bioclastic bands Metric Conversion Factor-"1 foof = 0.3048m © © ©"©. -- . ' . -. Thornloe Formation (Middle Silurian) •'i.;, '^ . ;- ::. CREDITS -; .;-;-^ .v.- -, [ The Thornloe Formation is characterized by massive-bedded scarp- forming dolostones The base *s marked by a thicK bed of pentamend- bearmg very fine grained to sublithograhic, light grey to creamy dolo : GeologybyD J Russell. 1981. 1983. . -© . "©© ©-- - stone, at 8 7 rn depth in LT-1, and 36.4 rn above lake level on the Daw son Point section. This unit forms the bulk of the outcrop of Paleozoic . Every .possible effort has been made to ensure the accuracy of the in rack north and east of New Liskeard in general, the lower part ot the for -. formation presented oh this map; however, the Ontario Ministry of Natu- mation is buff or brown, very fine to medium crystalline dolostone with - ::; ral Resources does-not-assume afly liability for errors that may occur abundant silicified corals and stromatolites or chert nodules; the upper ©:-JUsers may wish to verify critical information, sources include bofh the part is very fine to finely crystalline licht greenish or bluish grey dolo - . references listed here, and information on file at the Resident or Regional stone As such, the sequence resembies^tne Fossil Hill-Amabel Forma -.^Geologist©s office and the Mining Recorder©s office nearest the map tion sequence of Manitoulin Island However, the 2 Mhoiogies are fre quently laterally transitional, and in some cases, the sequence is apparently inverted This evidence of lateral facies variation is reflected ;, f-Jssued1984 © '-- V. ; . '\. * :j-\\ :,,.'/'. •••'' ,~o.\*^ -. © , :. in the grouping together ol Ihese lithologies into the single formation. - ©; j- --© , ^. -, . p . ;© :.-.©-\. .-©, - ©©f -©-.©© ; . ©©,- Since the top o) the Thornloe Formation is not exposed (although younger beds may be present in the centre of the fault block under tlrck .© - .; Information from this publication may be quoted if credil is given l! is overburden), an approximate minimum thickness only can be estab " .recommended that reference De made, in the following form. ^ . © lished. Approximately 35 m of Thornloe Formation is exposed on the ^ ! ' -^.W ^ eastern side of Dawson Point, very little is of the upper, Amabel-type, li , - t Russell, D.J- - ,- '~" : . '.' ^-' . . ( ©.: ; .© " ©./©- - v thology. On Milberta Creek (NC 901741), approximately 40 rn of mas .on." ^ 1984-.©Paleo2oic Geology of the©Lake Timiskaming. Area, Timiskaming sive, Amabel-like units outcrop dipping east between the 2 major bound : ,- District; Ontario Geological Survey Map P2700, Geological Se^ ary faults. Thus, a reasonable estimate of the maximum thickness of the . - ©- ries-PreliminaryMap scale 1:50000 Geology.1981. 1983 Thornloe Formation is 70 m. 80 00