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ONTARIO DEPARTMENT OF MINES
OPERATION LINGMAN LAKE
By
G. BENNETT and R.A. RILEY
MARCH, 1969 Crown copyrights reserved. This book may not be reproduced in whole or in part, without the permission of the Ontario Department of Mines.
Publications of the Ontario Department of Mines and price list
are obtainable through the
Publications Office, Ontario Department of Mines, Parliament Buildings, Queen©s Park, Toronto, Ontario.
Orders for publications should be accompanied by cheque, or money order, payable to Treasurer of Ontario. Stamps are not acceptable. Page
Abstract ...... vi Introduction ...... l Location and Access ...... l Resident Population ...... 3 Natural Resources ...... 3 Previous Work ...... 4 Present Geological Survey ...... 4 Acknowledgments ...... 5 General Geology ...... 7 Sandy Lake Metavolcanic-Metasedimentary Belt ...... 7 Mafic Metavolcanics ...... 7 Felsic Metavolcanics ...... 10 Metasediments ...... 10 Iron Formation ...... 10 Metagabbro Sills ...... 12 Structure ...... 12 Economic Geology ...... 12 Gold and Silver ...... 12 Lingman Lake Metavolcanic-Metasedimentary Belt ...... 14 Mafic Metavolcanics ...... 14 Felsic to Intermediate Metavolcanics ...... 14 Metasediments ...... 14 Seeber Lake Gabbro ...... 15 Diabase ...... 15 Minor Intrusions ...... 16 Economic Geology ...... 16 Base Metals ...... 16 Molybdenum ...... 16 Gold ...... 17 Lakelyn Mines Limited ...... 17 Pierce Lake - Ponask Lake - Sachigo Lake Belt ...... 18 Mafic to Intermediate Metavolcanics ...... 18 Felsic to Intermediate Metavolcanics ...... 18 Metasediments ...... 18 Mafic Intrusive Rocks ...... 19 Structure ...... 19 Economic Geology ...... 20 Base Metals ...... 20 Gold ...... 20 Stull Lake Belt ...... 20 Mafic to Intermediate Metavolcanics ...... 21 Felsic to Intermediate Metavolcanics ...... 21 Metasediments ...... 22 Intermediate to Mafic Intrusive Rocks ...... 22 Minor Felsic Intrusions ...... 22 Economic Geology ...... 22 Gold ...... 22 Base Metals ...... 23 Muskrat Dam Lake Belt ...... 23 Mafic to Intermediate Metavolcanics ...... 24 Felsic to Intermediate Metavolcanics ...... 24 Page
Metasediments ...... 25 Iron Formation ...... 25 Intrusive Rocks ...... 26 Structural Geology ...... 26 Economic Geology ...... 26 Big Trout Lake - Swan Lake Belt ...... 27 Mafic to Intermediate Metavolcanics ...... 27 Felsic to Intermediate Metavolcanics ...... 28 Metasediments ...... 28 Mafic Intrusive Rocks ...... 28 Economic Geology ...... 29 Gold ...... 29 Base Metals and Related Sulphides ...... 29 Blackbear River - Ellard Lake Belt ...... 30 Mafic Metavolcanics and Metagabbro ...... 30 Felsic Metavolcanics ...... 30 Metasediments ...... 31 Structural Geology ...... ,...... 31 Economic Geology ...... 31 Gold ...... 31 Sachigo River Exploration Company ...... 31 Silver ...... 33 Thorne River - Sachigo River Belts ...... 33 Economic Geology ...... 34 Base Metals ...... 34 Northern Belt ...... 34 Economic Geology ...... 35 Base Metals and Related Sulphides ...... 35 Azure Lake Belt ...... 35 Economic Geology ...... 35 Silver and Lead ...... 35 Sagawitchewan Belt ...... 36 Economic Geology ...... 36 Gold ...... 36 Witegoo River Belt ...... 36 Economic Geology ...... 37 Other Metavolcanic Belts ...... 37 Intermediate Intrusive Rocks ...... 37 Granitic Batholiths ...... 38 Hybrid Granitic Rocks ...... 39 Migmatite ...... 39 Syenitic Rocks ...... 39 Carb Lake Carbonatite ...... 40 Pleistocene Geology ...... 44 Direction of Ice Movement ...... 44 Moraines ...... 44 Eskers ...... 45 Glaciolacustrine Deposits ...... 45 Recommendations for Future Exploration ...... 48 References Cited ...... 50
- iv - FIGURES Page
1. Operation Lingman Lake, index to geological and aeromagnetic maps ...... 2 2. Operation Lingman Lake, geology ...... 8 3. Sachigo River Exploration Co. Ltd., cross section ...... 32 4. Aeromagnetic map of the Carb Lake Carbonatite ...... 41 5. Operation Lingman Lake, Pleistocene features ...... 46
- v - ABSTRACT
About 20,000 square miles of northwestern Ontario were mapped, and preliminary maps were published on a scale of l inch to 2 miles. The oldest rocks in the area are early Precambrian metasediments and metavolcanics which form 18 east-, south-southeast- and locally northeast- trending belts within granitic batholiths. The metavolcanic-metasedimentary belts have been subjected to at least one period of folding and the metamorphic grade ranges from greenschist to almandine amphibolite facies. Granitic rocks underlie about 80 percent of the area and range in composition from quartz diorite to granite. Local bodies of syenite and granite probably represent the latest phase of granitic intrusion.
The northeastern portion of the area is underlain by generally flat- lying Paleozoic rocks. Most of the area is blanketed by Pleistocene and Recent sediments. Occurrences of copper, zinc, lead, nickel, silver, gold, molybdenum, and iron are reported in the area. A carbonatite intrusion contains columbium (niobium) and rare-earth elements. One former gold producer, and one gold deposit in an advanced stage of development, occur in the area.
- vi - OPERATION LINGMAN LAKE
By
G. Bennett 1 and R.A. Riley2
INTRODUCTION
In 1967, Operation Lingman Lake, the second in a series of helicopter supported, reconnaissance, geological mapping projects was carried out by the Geological Branch of the Ontario Department of Mines. These projects are designed to provide reconnaissance geological maps of the relatively unmapped parts of Ontario in the shortest possible time. Nine uncoloured preliminary maps covering the area of Operation Lingman Lake have been published at a scale of one inch equals two miles (Figure 1). Final coloured maps will be released as part of the Ontario Department of Mines compilation series at a scale of one inch equals four miles.
Location and Access
The territory covered by Operation Lingman Lake is located in extreme northwestern Ontario and lies within the Patricia Portion of the District of Kenora. It comprises approximately 20,000 square miles; the boundaries of which are shown in Figure 1.
The area lies within one of the more remote parts of Ontario; the nearest mainline railway is about 250 miles south of the centre of the map-area, and the nearest all-weather road ends at Central Patricia about 170 miles southeast of the centre of the map-area.
Construction has begun on all-weather roads from Red Lake and Central Patricia to the vicinity of North Spirit Lake, but it will be several years before these roads are completed. The supply points nearest to the centre of the map-area are Red Lake (230 miles), Central Patricia (170 miles) and Sioux Lookout (270 miles).
At present the only efficient means of gaining access to this part of Ontario is by air. There is a bi-weekly scheduled flight from Red Lake to Sandy Lake and a weekly scheduled flight from Pickle Lake to Bearskin Lake via Big Trout Lake. Bi-weekly scheduled flights between Fort William and Sandy Lake with stops at Red Lake, Deer Lake and Pikangikum began in 1968. In addition to these scheduled flights, aircraft can be chartered at Red Lake, Pickle Lake, and Sioux Lookout. Aircraft can also be chartered from Big Trout Lake for local service. geologist, Ontario Department of Mines, Toronto. Resident Geologist, Ontario Department of Mines, Red Lake, Ontario. Accepted for publication by The Director, Geological Branch, 19 February 1969 - 2 -
Figure l
OPERATION LINGMAN LAKE INDEX TO GEOLOGICAL AND AEROMAGNETIC MAPS
55 During the summer float-equipped aircraft can land on most of the larger lakes in the southern half of the area. Many of these lakes, however, are quite muddy, particularly following "break-up", and it would be wise to seek advice from the many veteran "bush" pilots at Red Lake or Sioux Lookout before planning camp sites. Many of the large lakes in the northern half of the area are shallow and are not safe for float-equipped aircraft. During the winter months most of the heavy freight, fuel oil, imperishable foodstuffs, etc. is transported to the settlements within the area by tractor trains with bases at Dog Head, Manitoba and Savant Lake, Ontario. During the winter of 1968-1969 ski-equipped Douglas DC-3 aircraft will begin transporting some supplies to Sandy Lake.
Resident Population At present there are only three permanent settlements of any consequence within the boundaries of the map-area. Of these, Sandy Lake is the largest, with a population of about 700, followed by Bearskin Lake with a population of about 170, and Sachigo with a population of about 70. A settlement on Muskrat Dam Lake has a population of about 30 summer residents but most of these return to Bearskin Lake for the winter. The villages are populated almost entirely by North American Indians of Cree or mixed Cree-Ojibway stock. The remainder of the population comprises missionaries, personnel of the Hudson©s Bay Company and independent traders, and nurses and school teachers employed by the Indian Affairs Branch, Department of Indian Affairs and Northern Development.
Natural Resources The area is almost entirely forested with black spruce and balsam fir predominating; jackpine is restricted to the more well drained eskers and moraines. Most of the evergreens are small, and large trees are found only on the well drained banks of the larger rivers. The large trees are seldom found more than 1/4 mile inland from the river. Sawing of rough timber is currently being carried out at Sandy Lake. Poplar and birch are the most abundant deciduous trees. There are a few good stands around Sandy Lake and Lingman Lake. Tamarack is common in the swampy areas. Although they are hunted regularly by the Indians, moose were sighted rarely and only five caribou were seen over the entire summer. No bear were sighted. Ducks and geese are plentiful around Big Trout Lake and around Bearskin Lake in late August and September. Pickerel and pike can be caught in most of the larger lakes and streams. Local residents report sturgeon to be plentiful in the Severn and Fawn Rivers. Azure Lake and Big Trout Lake contain an abundant supply of lake trout. Speckled trout are reported to be plentiful in the Echoing River (Satterly, 1937b, p.9). - 4 -
Previous Work
In 1886, A.P. Low (1887) travelled the Severn River from Lake Winnipeg to Hudson©s Bay and noted the presence of the metavolcanic rocks in the map-area. In 1912 a similar trip made by J.B. Tyrrell (1913) gave more information of geological nature. In 1928, M.E. Hurst (1929) mapped the shores of Angekum, Opasquia and Finger Lakes, and the western part of Sandy Lake. D.R. Derry and G.S. MacKenzie (1931) in 1930, mapped the Ontario- Manitoba boundary and some adjacent lakes and rivers from south of the map- area to the Sagawitchewan metavolcanic metasedimentary belt. In 1936, J. Satterly (1937b) mapped most of the Stull Lake, Lingman Lake and Pierce- Ponask-Sachigo Lake belts. At the same time V.B. Meen (1937) mapped the western part of the Blackbear River-Ellard Lake and Big Trout Lake-Swan Lake belts, and the eastern part of the Thorne River-Sachigo River belt. Satterly (1938) also mapped the Sandy Lake area in 1937 and part of the North Caribou Lake area, mapped by Satterly in 1938, extends into the southern part of the map-area (Satterly, 1939). In 1960 and 1961, P.P. Hudec (1964) mapped the area around Big Trout Lake. L.D. Ayres (1966) mapped the Muskrat Dam and Rottenfish River belts, and surrounding granitic areas in 1963 and 1964.
Present Geological Survey
The field party consisted of two staff geologists, five senior assistants, five junior assistants, one cook, and a helicopter pilot and an engineer. A Bell model 47-J2 helicopter, and a Cessna 180 fixed-wing aircraft were obtained under contract for the duration of the field season. In addition, DeHavilland Beaver and Beach 18 aircraft were chartered for major camp moves, distribution of gasoline caches, and camp servicing.
Base-camps were established at Sandy Lake (June), Lingman Lake (July), and Bearskin (August and part of September). Supplies of gasoline, propane and some building materials were shipped to Sandy Lake, Bearskin Lake and Red Sucker Lake in Manitoba by tractor train in February and March, 1967. The gasoline at Red Sucker Lake was shipped by air to Lingman Lake in June, 1967.
At Sandy and Bearskin Lakes most camp supplies and food could be purchased at Hudson©s Bay stores; the Lingman Lake camp was serviced by weekly chartered flights from Red Lake. The following methods of reconnaissance geological mapping were employed: (1) Mapping parties of two men were flown by helicopter or fixed-wing aircraft to the beginning of a pre-arranged traverse and returned to base camp on completion of the traverse in the afternoon. In this manner up to three mapping parties could be deployed within a radius of 30 miles from the camp. Foot traversing was carried out only over metavolcanic- metasedimentary belts. (2) The helicopter and Cessna were used to transport two men and a canoe or folding rubber boat to large lakes and rivers where the men remained until their mapping assignment was completed. In cases where two-man "fly-camps" were set up, supplies and mail were flown in at least once a week by helicopter or fixed-wing aircraft. (3) The helicopter was used extensively for rapid reconnaissance mapping of granitic areas, small metavolcanic belts and otherwise inaccessible parts of large belts. - 5 -
This method was found to be most efficient in the northern half of the area where numerous small lakes and swamps permitted landing adjacent to most outcrops. Most of the area north of 54 0 30© was mapped by this method.
A total of about 325 hours were flown using the helicopter and 200 hours using the Cessna; utilization of the helicopter time was about as follows:
(a) 65% geological reconnaissance. (b) 25% transportation of traversing, and canoe parties. (c) 5% servicing of canoe parties. (d) 5% ferry time. The utilization of the Cessna time was about as follows:
(a) 30% servicing of canoe parties. (b) 15% systematic searching for outcrop. (c) 15% servicing of base camp. (d) 25% transportation of traversing and canoe parties. (e) 10% flying related to maintenance of helicopter. (f) 5% ferry time.
The data collected was plotted on one inch to one mile aerial photographs and transferred to one inch to two miles base maps for preliminary publication.
Acknowledgments
J.L. Wallach, S.W. Burnie, D.R. Rota, B.W. Mccammon and L.C. Gobeil acted as senior assistants and did independent mapping throughout most of the field season. V.J. Sopuck, J.P. Scholz, G.R. Wright, D.I. Wilkes and K.H. Hamm acted as junior assistants. Sopuck and Hamm did some independent mapping near the end of the field season.
The advice and assistance of L.D. Ayres of the Ontario Department of Mines was of great value at all stages of the project.
The writers would also like to thank Dr. J.C. Davies for his valuable assistance in the field.
The willingness and co-operation of the personnel of Pegasus Airlifts is greatly appreciated. Ontario Central Airways provided excellent service throughout the field season.
- 7 -
GENERAL GEOLOGY
The oldest rocks in the map-area are those of the early Precambrian metavolcanic-metasedimentary belts which underlie about 20 percent of the area. The youngest rocks present are the lower Paleozoic sedimentary rocks which underlie the northeastern corner of the area1 . The remainder of the area is underlain by granitic batholiths and related rocks, also of early Precambrian age. Two distinct trends of the metavolcanic-metasedimentary belts can be recognized (Figure 2). One is the easterly trend typical of the Superior Province which is shown by belts labelled A, C, H, T and U; whereas belts labelled D, E, I, K, and J exhibit a more southeasterly trend. The latter belts tend to occur in a 65-mile wide zone which trends southeast through the central part of the map-area. An elongate magnetic anomaly on 0.D.M.-G.S.C. aeromagnetic maps 3693G, 3692G, and 3704G extends southeastward from Rieder Lake for a distance of about 80 miles. This anomaly appears to reflect a major fault or shear zone which truncates the metavolcanic-metasedimentary belt labelled H on Figure 2. The presence of many other faults and shear zones in the granitic batholiths is suggested by numerous lineaments on aerial photographs.
SANDY LAKE METAVOLCANIC-METASEDIMENTARY BELT
(Labelled A, Figure 2; O.D.M. P.431, P.4322) The Sandy Lake belt is about 50 miles long and has a maximum width of about 10 to 15 miles. Mafic to intermediate volcanics which have undergone metamorphism to greenschist and almandine amphibolite facies make up 80 to 90 percent of the belt. The remainder of the belt is felsic to intermediate metavolcanics, metasediments, and metagabbro.
Mafic Metavolcanics The mafic metavolcanics of the Sandy Lake belt are dark green to almost black on the fresh surface and are various shades of grey or greenish grey on the weathered surfaces. They vary from essentially massive to strongly foliated, but, in thin section even the massive varieties are seen to possess a slightly oriented fabric. Pillow structures are widely distributed, but undeformed pillows suitable for top determinations are not abundant. The mineral assemblage of specimens examined in thin section is typically;
Because of logistics problems the Paleozoic rocks were not mapped during the present survey. For information on the Paleozoic rocks see Sanford 2et.aK (1968). Numbers prefixed by letter "P" refers to Ontario Department of Mines Preliminary map (or maps) which includes the belt under discussion. 55© Figure 2 OPERATION LINGMAN LAKE GEOLOGY
LEGEND
Paleozoic and Younger Rocks Metasediments
Carbonatite-Alkalic Complex Metavolcanics
Diabase (dike) Major fault
Granitic Rocks
Reference to Metagabbro and Metadiorite " Greenstone" Belt
54© -9-
55©
Si© - 10 -
albite + blue-green amphibole ^ epidote -^ chlorite * carbonate (greenschist facies), or oligoclase - andesine - green hornblende * epidote * carbonate garnet (almandine amphibolite facies) . ~~ ~~
Felsic Metavolcanics
Felsic to intermediate metavolcanics are most abundant along the north shore of the Northwest Arm of Sandy Lake where they form a distinctive pyroclastic unit containing characteristic "eyes" of bluish quartz. Satterly (1938) classified this rock as a dacite porphyry on the basis of chemical analysis and thin section study. Thin section study by the authors support this conclusion. The unit largely consists of a pale grey to green rock, which contains many lapilli-sized fragments set in an aphanitic, massive to faintly foliated matrix; the phenocrysts described by Satterly (1938, p. 17) are crystal lapilli. The rock is therefore a dacitic tuff, although dacitic flows and sills may also be present in minor amounts. Some mafic metavolcanic flows are intercalated with the felsic metavolcanics along the Northwest Arm of Sandy Lake. The felsic metavolcanics become less abundant as one proceeds eastward along the north shore of Sandy Lake. In the eastern half of the lake felsic to intermediate metavolcanics are rare.
Metasediments
Most of the metasediments are restricted to the western half of Sandy Lake. Conglomerate, metagreywacke and cordierite-biotite hornfels, biotite-quartz-plagioclase hornfels (See Table l, analysis 9) form the bulk of the metasedimentary assemblage.
Polymictic pebble conglomerate outcrops at the extreme west end of the West Arm of the lake and on an island about l 1/2 miles southwest of the settlement. The conglomerate consists mainly of chert pebbles with minor amounts of granitic and volcanic pebbles.
Quartzite and greywacke outcrop around Colgrove Lake and the extreme West Arm of Sandy Lake. Quartzite is also interbedded with phyllite and cordierite-bearing hornfels on many of the islands in the main body of Sandy Lake. The quartzite and greywacke can be identified by their commonly reddish-brown tint on the fresh surface and the common occurrence of limonite-hematite staining on the outcrops. They are generally fine-grained but locally contain visible grains of bluish quartz.
Iron Formation
Beds of iron formation from less than a foot up to 200 feet thick are interbedded with mafic metavolcanics at several localities around the lake. Satterly (1938, p. 16) states "The iron formation is of three types, one composed of magnetite and white sugary quartz; another of magnetite, chlorite and blue-grey quartz bands; and the third of black chert and magnetite". Iron formation is most abundant along the north shore of the main body of Sandy Lake and causes strong anomalies on O.D.M.-G.S.C. aeromagnetic maps 3662G and 3670G. - 11 -
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Metagabbro Sills
Two metagabbro sills underlie a large part of the islands in the main part of Sandy Lake. Satterly (1938, p. 27) traced these sills from Sandborn Bay, northeastward for a distance of 23 miles. The sills trend about N80 0 E and the thicker sill has an outcrop width of about 2000 feet. The typical metagabbro is dark-green on fresh surfaces, weathers to a somewhat paler green, and is medium- to coarse-grained. Subhedral crystals of green amphibole up to 5 millimetres across are conspicuous and form about 50 percent of the rock with dark grey plagioclase filling the interstices. The metagabbro has undergone extensive recrystallization but the chemical analysis of a typical specimen given in Table l (analysis 1) shows the gabbroic composition of the rock.
Structure
It is evident that rocks of the Sandy Lake belt have undergone at least two periods of folding. The first period of folding produced three east- trending isoclinal folds, a central anticline and two flanking synclines (Satterly, 1938). The anticlinal axis trends through the main part of Sandy Lake and the northern syncline trends through the west arm of Sandy Lake and Colgrove Lake. The second period of folding produced northeast-trending cross folds at the west end and possibly the east end of the belt.
Data collected during the field season were insufficient to modify Satterly©s interpretation. However, it was concluded that there is good evidence for an east-striking fault through the islands in the middle of the lake and continuing eastward through the narrows which join the main body of the lake with the West and Northwest Arms. This fault is believed to separate the granitic rocks from the metasedimentary-metavolcanic rocks in the main body of Sandy Lake. Evidence for this fault includes mylonitization adjacent to the contact and the linear nature of the contact itself over most of its length. Another major fault truncates the metavolcanics of the Northwest Arm along the east shore of Finger Lake. This fault extends southwest through a major cross-fold at the west end of Sandy Lake belt. The horizontal component of movement on this fault appears to have been right-handed but there is probably a major vertical component of unknown extent.
ECONOMIC GEOLOGY
Gold and Silver Prospectors were active in the Sandy Lake area during the mid-1930©s. Satterly (1938, p. 38-43) described fourteen prospects, most of which were gold showings in shear zones or quartz veins. Gold values of samples collected for assay by Satterly were low (generally less than 0.1 ounces per ton); and minor chalcopyrite, galena or sphalerite occur in some of the showings. The location of these old showings are shown on the Finger Lake and Rottenfish River Sheets of Operation Lingman Lake (O.D.M., P.431, - 13 -
P.432). Further information is available in the report of Satterly (1938). Occurrences described below are those which were found subsequent to Satterly©s work. During 1945 and 1946 Berens River Mines Limited did surface work and diamond drilling on a number of showings located in an area between 3 to 5 miles east of the settlement of Sandy Lake and between the Stain River and Sandy Lake. The most interesting of these showings is about 4 3/4 miles east of the settlement. Here, a silicified, rusty weathering zone which has an average width of 2 1/2 to 3 feet and a maximum width of 6 feet trends S770 E in pillowed mafic metavolcanics and has been traced along strike for 250 feet. Pyrite and chalcopyrite are most abundant where the zone is narrow. Two grab samples taken from this showing by the junior author during the summer of 1967 were assayed by the Laboratory Branch, Ontario Department of Mines and were found to contain 1.90 and 0.85 ounces of gold per ton, 2.85 and 1.10 ounces of silver per ton, and 1.90 and 0.87 percent copper. The zone had been trenched over most of its length. A quartz vein trending N78 0E, about 10 to 12 inches wide and 150 feet long is exposed by 5 old trenches about 1/4 mile southwest of the showing described above. The vein contains scattered knots and veinlets of pyrite which gave an assay of 0.2 ounces of gold per ton. The country rocks are mafic metavolcanics. Another rusty-weathering area, 3 to 4 feet across is exposed on the shore of Sandy Lake about three miles east of the settlement. Stripping and trenching has been done on the showing but mineralization is scarce. A grab sample of a quartz vein 3 to 4 inches wide, trending N85 0E in the rusty zone assayed 0.03 oz. of gold per ton. An island about two miles south of the settlement of Sandy Lake consists in part of conglomerate and sandstone. A 6-inch wide gossan zone in the sandstone was sampled and gave upon assay 0.03 ounces of gold per ton. The zone trends N400E. A gossan zone about one foot wide and ten feet long, trends N80 0E in metasediments at Latitude 53 0 00©, Longitude 930 15© on the shore of Sandy Lake. A specimen of massive pyrite from this zone contained a few specks of sphalerite but when assayed gave very low values in zinc. In 1968 Mentor Exploration 5 Development Co. Ltd. staked two groups of claims in the Sandy Lake belt to cover many of the gold showings described by Satterly. The Algoma Steel Corporation Limited has also done some recent work on claims north of the central part of Sandy Lake. It is believed that they are investigating the iron formation in that area. - 14 -
LINGMAN LAKE METAVOLCANIC-METASEDIMENTARY BELT
(Labelled C, Figure 2; O.D.M. P.431, P.432) The Lingman Lake belt is approximately 20 miles long and 10 miles wide and it is essentially an east-trending syncline. The lithologic assemblage, from bottom to top, may be generalized as (1) amphibolite which is predominantly mafic metavolcanics but may include some thick metagabbro sills; (2) quartz latite metatuff and flows; (3) greywacke, slate, quartzite, and local conglomerate; (4) mafic metavolcanics with early gabbroic sills. All of these rocks are presumably of early Precambrian age and have been intruded in turn by quartz-feldspar porphyry, quartz-bearing gabbro, granitic rocks and diabase.
Mafic Metavolcanics A chemical analysis of a typical specimen of metabasalt from the Lingman Lake belt is given in Table l, analysis 3. Pillow structures are relatively common south of Lingman and Seeber Lakes, and it may be possible to delineate a marker unit of pillowed metavolcanics with more detailed mapping. In general the mafic metavolcanics have been converted to amphibolites of the almandine amphibolite facies near the edges of the belt, but greenschist facies metavolcanics do occur in the central parts of the belt. The mineralogy and structure of these rocks is essentially the same as that of amphibolites of the Sandy Lake belt. Medium- to coarse- grained, massive amphibolite which is either metagabbro or metamorphosed thick mafic flows is prominent along the south shore of Lingman Lake and north of Seeber Lake.
Felsic to Intermediate Metavolcanics The most extensive exposures of felsic metavolcanics are found in a deep bay at the south end of Seeber Lake. These are predominantly grey to dark-grey quartz latite and dacite tuff and agglomerate containing lapilli-size to bomb-size fragments in an aphanitic to "porphyritic" matrix, Islands in the bay at the south end of Seeber Lake consist mainly of a very fine-grained, massive, microporphyritic quartz latite (Table l, analysis 5), that on the fresh surface has a distinctive apple-green colour. This quartz latite may be a very thick flow or a welded tuff. Felsic to intermediate metavolcanics extend eastward from the southeast end of Seeber Lake to the southwest shore of Lingman Lake but they do not appear to be important in the eastern half of the belt.
Metasediments A metasedimentary unit ranging in width from 1/4 mile to at least l 1/2 miles trends easterly through the central portion of the belt. Metasediments which outcrop along the south shore of Lingman Lake are fine grained, grey quartzite and greywacke. Bedding is poorly preserved and in - 15 - places the prominent foliation is at least 20 degrees discordant to the bedding. The presence of about 10 percent andalusite in amphibolite facies metasediments on Lingman Lake implies the presence of a former argillaceous matrix. Metagreywacke with thin slate interbeds outcrop on an island in the eastern part of Seeber Lake. Here, graded bedding indicates that the beds are overturned towards the north. A thin layer of relatively pure, white quartzite lies within the metavolcanics about two miles north of the main metasedimentary unit. In places the quartzite contains a few pebbles of chert and grades laterally into chert-pebble conglomerate. At the extreme east end of the Lingman Lake belt a thin unit of grey marble was found in the granitic batholith and is separated from the belt by the granitic rocks. The marble can be traced for only a few hundred feet and its relationship to rocks of the belt is unknown.
Seeber Lake Gabbro A wide body of quartz-bearing gabbro with an overall length of about seven miles has been intruded between felsic and mafic metavolcanics on Seeber Lake. The gabbro is massive and has an equigranular to sub-ophitic texture, and has been extensively altered with the development of much uralite, leucoxene, epidote and calcite; the plagioclase is highly saussuritized. Quartz and iron-titanium oxides each form less than one percent of the rock. The gabbro has little or no magnetic expression on aeromagnetic maps.
Diabase A post-granitic diabase dike approximately 200 feet wide trends about N100E through the Lingman Lake belt. This dike can be traced from rock exposures and on aeromagnetic maps from Stull Lake in the north, through Lingman Lake and Sandy Lake to Setting Net Lake in the south (L.D. Ayres, personal communication). This is a distance of at least 140 miles. At the west end of Lingman Lake the dike has been extensively altered and similar alteration extends into the wallrock for at least 50 feet on both sides of the dike. The alteration appears to be essentially hydrothermal with the development of white mica, talc, chlorite and uralite The plagioclase of the dike has been highly saussuritized and all of the original pyroxene has been converted to uralite and chlorite. Highly saussuritized anorthosite, apparently a phase of the dike, occurs about 1/2 mile north of Lingman Lake. About two miles south of Lingman Lake the diabase is unaltered and has a fine-grained margin with a medium-grained, equigranular central portion. The essential minerals are labradorite (50 percent), clinopyroxene (40 percent), and iron-titanium oxides (5-7 percent). Minor alteration products are uralite, epidote, and serpentine; the serpentine appears to have totally replaced original olivine. - 16 -
Minor Intrusions A group of three small islands in the northwest part of Seeber Lake consist of quartz-feldspar porphyry. Other minor porphyry intrusions were recognized near Lingman, Durrell Lakes. Satterly (1937b, p.20) describes the porphyry on Seeber Lake as follows: "... a dark porphyry has blue opalescent eyes of quartz, and greenish grey phenocrysts of feldspar one twentieth of an inch in diameter ... the rock is seen to consist of acid andesine, quartz, biotite, secondary chlorite and epidote, and accessory apatite and pyrite. It is a quartz diorite porphyry". Other occurrences of porphyry in the Lingman Lake belt are similar to the one described by Satterly except that oligoclase may be present instead of andesine and muscovite may occur in place of biotite. The relative age of the quartz-feldspar porphyry is uncertain. Although it was included with the granitic rock in the legend of the preliminary maps of Operation Lingman Lake, the porphyry may be much older and may even be related to the felsic metavolcanics. A few narrow, grey, fine-grained mafic dikes containing clots of pyrite and epidote intrude the metavolcanics of the Lingman Lake belt. The relationship of these dikes to other intrusive rocks is unknown.
ECONOMIC GEOLOGY
Base Metals International Minerals and Chemicals Ltd. were active in the Lingman Lake belt during 1965, 1966 and 1967. About 420 claims were recorded on the basis of airborne magnetic and electromagnetic surveys. As of the spring of 1968 twenty diamond drill holes were submitted for assessment work, and geological mapping and prospecting had been carried out over much of the belt. Geological maps submitted for assessment credits show the location of five occurrences of pyrite, pyrrhotite and chalcopyrite in the Lingman Lake belt. The location of these occurrences is shown on the Finger Lake and Rottenfish River Sheets of Operation Lingman Lake (O.D.M. P.431, P.432).
Kennco Explorations (Canada) Limited carried out airborne electromagnetic and magnetic surveys over the Lingman Lake belt in 1960. Reconnaissance geological mapping and prospecting were done but no claims were recorded. The company is no longer active in the area.
Molybdenum A six-inch wide quartz vein striking N30 0W in coarse-grained mafic metavolcanics about 1/2 mile north of Lingman Lake was found to contain specks of molybdenite. A grab sample gave an assay of 0.12 percent molybdenum and trace amounts of gold and silver. No other sulphides were visible in the vein. - 17 -
Gold Gold was discovered in the belt in 1945 by Lingman Lake Gold Mines Limited, and a staking rush was precipitated. Many companies acquired properties along the north shore of Lingman Lake and between Lingman Lake and Seeber Lake. In addition to Lingman Lake Gold Mines Limited the following companies carried out trenching, geophysical surveys and diamond drilling between 1945 and 1948; Lingnora Gold Mines Limited, Lingside Gold Mines Limited (now Lingside Copper Mining Company Limited), Lingman Lake Gold Mines Limited (now Lakelyn Mines Limited), Winora Gold Mines Limited (now Roman Corporation Limited), and Lingkey Gold Mines Limited; three of these companies still hold property in the area. These properties are listed in geographical order from west to east.
Lakelyn Mines Limited (Formerly Lingman Lake Gold Mines Limited, Lake Lingman Gold Mining Company Limited) Lakelyn Mines Limited holds 21 patented claims about one mile north of the west end of Lingman Lake. The claims were staked in 1945. In 1945 and 1946 an extensive diamond drilling program was carried out which outlined two gold-bearing shear zones. In 1946 a three-compartment shaft was sunk to a depth of 300 feet on claim Pa6132 and levels were opened at 150 and 275 feet; the shaft was deepened to 422 feet in 1948 with an additional level at 400 feet. Drifting and extensive underground diamond drilling outlined 148,000 tons of ore averaging 0.48 ounces of gold per ton. The property has been more or less inactive since 1949 (Canadian Mines Handbook, 1968). The following summary of the geology is taken from the reports of consulting engineers J.A. Reid and M.G. Smerchanski on file at the office of the Resident Geologist at Red Lake. Gold occurs in four shear zones which trend east to east-northeast in mafic metavolcanics cut by quartz porphyry about 600 feet south to the northern edge of the Lingman Lake belt. The most promising showings occur in two of these zones, known as the North Zone and the South Zone; each about 200 feet long and cut off at their western end by a 200-foot thick diabase dike. The North and South zones are believed to dip about 65 degrees to the south, are about 250 to 400 feet apart, and appear to diverge toward the west. The vein material is mostly silicified mafic to intermediate metavolcanics with some carbonate and quartz. Gold values are said to be especially good near the ends of small bodies of quartz porphyry. Sulphide mineralization is described as being good, but not particularly heavy or massive. The main sulphides are pyrite with minor pyrrhotite, arsenopyrite and chalcopyrite. Visible gold is very rare. - 18 -
PIERCE LAKE - PONASK LAKE - SACHIGO LAKE BELT
(Labelled D, Figure 2; O.D.M. P.426, P.432)
This major metavolcanic-metasedimentary belt extends from Manitoba, through the southern arm of Pierce Lake and Ponask Lake to east of Sachigo Lake where it ends abruptly, a total distance of more than 60 miles. The Pierce Lake section of the belt has a uniform width of about 10 miles and outcrops along a narrow east-west trending arm which forms the extreme southern part of Pierce Lake. About four miles east of Pierce Lake the belt bends sharply to the southeast and continues on through Ponask and Sachigo Lakes.
Mafic to Intermediate Metavolcanics
The Pierce Lake section of the belt consists predominantly of amphibolite which is derived from mafic to intermediate volcanic rocks. Narrow beds of metagreywacke and probably metatuff are interbedded with the amphibolite at a few localities. Most of the metavolcanics on Pierce Lake appear to have been metamorphosed to upper greenschist and almandine amphibolite facies of regional metamorphism.
Mafic metavolcanics form the edges of the Ponask-Sachigo Lakes section of the belt. These are mainly fine-grained to medium-grained, dark green to black amphibolites that have been metamorphosed to the almandine amphibolite facies. The degree of metamorphism and ubiquitous shearing has destroyed or distorted most primary structures. The only undistorted pillows were found about six miles northwest of Ponask Lake and on a few islands in Sachigo Lake.
Felsic to Intermediate Metavolcanics
The felsic to intermediate volcanics are more or less restricted to the Ponask Lake section of the belt, especially the northwest end of Ponask Lake. The felsic to intermediate metavolcanics are chalk-white to grey on weathered surfaces but on the fresh surfaces the colour varies from buff, pale-green, or yellow to almost black. They are typically aphanitic. Porphyritic types appear to be less abundant than in the other metavolcanic - metasedimentary belts of the map-area. In thin section the rocks are seen to be dacitic: clear, granular, untwinned plagioclase (Ans-20) predominates and is associated with finely granular quartz, micas and amphibolites.
Metasediments Two layers of grey and white quartzite that are 200 to 1000 feet wide extend for as much as six miles along the south shore of the long arm of Pierce Lake. Narrow beds of pale-grey to dark-grey slate and greywacke are interbedded with felsic metavolcanics at the northwest end of Ponask Lake, and a 1/4 to 1/2-mile wide metasedimentary unit extends along the entire length of the northeast shore of the lake. This unit comprises interbedded quartz-pebble conglomerate, granite-boulder conglomerate, sandstone and tuffaceous metasediments; the pebbles and boulders in the conglomerate are commonly stretched. - 19 -
Mafic Intrusive Rocks A body of mafic to ultramafic rocks about three square miles in area, intruded the felsic metavolcanics at the northwest end of Ponask Lake. Satterly (1937b, p. 18) described the body as follows: "The rock is massive, dark green, fine- to medium-grained, and greasy to the touch. Weathered or glaciated surfaces show a network of serpentine veinlets ... Under the microscope the rock is seen to be composed of an aggregate of well-defined areas of antigorite and carbonate ... the rock was therefore formerly a dunite". Additional sampling by the author©s assistants during the 1967 field season has shown that much of the body is pyroxenite, with minor mafic gabbro as well as dunite. The pyroxenite samples are predominantly pale-green amphibole which appears to have replaced pyroxene; carbonate, clinozoisite, and highly saussuritized plagioclase are minor constituents. The intrusion may therefore be a differentiated ultramafic stock. The intrusion is outlined by a strong aeromagnetic anomaly on O.D.M.-G.S.C. aeromagnetic map 3674G.
Structure Bedding, foliation, schistosity and shearing all dip subvertically and are generally conformable to the margins of the belt. The stratigraphy and structure of the Pierce Lake-Ponask Lake-Sachigo Lake belt could not be accurately defined during the reconnaissance survey. However, the major structure appears to be a syncline with felsic metavolcanics and metasediments overlying mafic metavolcanics. The thickening of the belt at the north end of Ponask Lake appears to be due to a combination of faulting and the intrusion of the ultramafic stock. A shear zone at least 15 feet wide is exposed on an island at the southeast end of Pierce Lake. The zone contains up to 50 percent calcite, and clots of pale-green amphibole forming crystals up to two inches long and euhedral crystals of pale-green diopside about three inches long are scattered through the calcite-rich portions. The remainder is made up of sheared and schistose mafic fragments derived from mafic volcanic rocks. The shear zone dips vertically or very steeply to the south, and strikes west through the long arm of the lake. It seems likely that a major fault underlies the waters of the southern arm of Pierce Lake. Aeromagnetic anomalies on 0.D.M.-G.S.C. aeromagnetic map 3674G suggests that the belt has been displaced by a northwest-trending fault at the point where it is bent to pass southeastward through Ponask Lake. Shear zones, carbonate veins, and to a lesser extent quartz veins, have been noted at numerous localities along the shore of Ponask Lake suggesting that a major fault extends along the length of Ponask Lake. - 20 -
ECONOMIC GEOLOGY
Base Metals
Kennco Explorations (Canada) Limited carried out airborne electromagnetic and magnetic surveys over the Ponask Lake belt in 1960. Anomalies were checked by ground electromagnetic and magnetic surveys and by diamond drilling. Mineralization was intersected in one hole drilled on the south shore of the middle part of Ponask Lake; here a company report states that seams of pyrite and chalcopyrite gave an assay of 0.14 percent copper over 10 feet of core length. No further work was done.
Exploration trenches in mafic metavolcanics, about four miles north of Ponask Lake, revealed a one-foot wide shear zone trending N30 0W containing narrow seams and blebs of pyrite, pyrrhotite and minor amounts of chalcopyrite and bornite. A grab sample collected by Ontario Department of Mines personnel was assayed by the Laboratory Branch of the Ontario Department of Mines, and was found to contain 0.26 percent copper. This occurrence is believed to have been trenched by Kennco Exploration Company Limited in 1960.
Asarco Exploration Company Limited carried out airborne geophysical surveys over Ponask Lake in 1967. They staked 125 claims and carried out a diamond drilling program during the summer of 1967, but geophysical and geological data has not yet been released by the company. No work was done during the winter of 1967-68.
Gold
Satterly (1937b, p.38) described four occurrences of mineralization on Ponask Lake. Grab samples collected by Satterly from two of these occurrences gave assays of 0.14 and 0.11 ounces of gold per ton respectively.
STULL LAKE BELT
(Labelled E, Figure 2; O.D.M. P.426)
The Stull Lake belt is exposed for a distance of about fifteen miles east of the Ontario-Manitoba boundary and has an average width of about nine miles. Its eastward extension is covered by the thick glacial deposits of the Sachigo interlobate moraine, but there is evidence from O.D.M.-G.S.C. aeromagnetic maps 3683G and 3691G the belt continues eastward under the moraine to join the Swan Lake belt.
The Stull Lake belt differs from other metavolcanic-metasedimentary belts of the region in that felsic to intermediate metavolcanics are more abundant than mafic metavolcanics. Satterly©s map (Satterly, 1937b) includes much of the felsic metavolcanics under his sedimentary group.
Satterly concluded on the basis of drag folds and bedding attitudes that the rocks were folded into an anticlinal structure with mafic - 21 - metavolcanics overlying a core of felsic metavolcanics, metasediments and gabbro. Downie (1938) correlated the mafic metavolcanics of the Stull Lake belt with the Hayes River Group of Manitoba and the metasediments with the younger Oxford Group. Such a correlation would necessitate a synclinal structure for the belt. Stretched pillows in north-facing mafic metavolcanics were found in the southern part of the belt, suggesting the major structure is a syncline. Unfortunately the pillows were too highly deformed for reliable top determinations and a search for primary structures elsewhere which could indicate stratigraphic tops proved fruitless.
Mafic to Intermediate Metavolcanics The mafic to intermediate metavolcanics of the Stull Lake belt are derived from andesitic and basaltic rocks. Near the edges of the belt they have been converted to fine-grained to medium-grained amphibolite, biotite-amphibole schist and layered amphibolite (Table l, analysis 2), the latter rock has a well developed segregation layering and resembles bedding but is a secondary structure. Shearing also appears to be better developed near the edges of the belt than elsewhere. Porphyritic basalt is exposed along the southwest shore of Rapson Bay and at the outlet to Wynne Bay. This unit is described by Satterly (1937b, p.10) as " ... a much altered rock. The phenocrysts of labradorite(?) are altered to white mica flakes; secondary green chlorite and calcite, and a brownish-green biotite make up the groundmass, with accessory apatite as large grains. The degree of metamorphism indicates that this porphyry is of the same age as the other Keewatin-type lavas and not of later pre-Cambrian age". Along the south shore of Richardson Arm amphibolite is interbedded with pillowed basalt; deeply pitted, massive basalt and andesitic pyroclastic rocks. In the central part of the belt the mafic metavolcanics tend to be more massive and chloritic.
Felsic to Intermediate Metavolcanics Felsic to intermediate metavolcanics are abundant in the Stull Lake belt, and are well exposed along the shore of the lake and on the many islands. These rocks have generally been metamorphosed to the upper part of the greenschist facies but locally only the middle greenschist facies was attained. Four southeast-trending felsic to intermediate metavolcanic units ranging from 1/2 to 2 miles wide can be traced for a lateral distance of 10 to 12 miles across the lake. For the most part these units are medium grey, fine-grained, bedded tuff with interbedded agglomerate and flows. The pyroclastic rocks are in places interbedded with minor amounts of metasediments which appear to contain reworked tuffaceous material. In thin section most specimens are found to exhibit a porphyritic or micro-porphyritic texture. Phenocrysts of plagioclase (Ann ^n) and quartz, - 22 -
which is sometimes deeply embayed, occur in a very fine-grained mosaic of quartz, feldspar and biotite and/or pale-green amphibole. Clinozoisite, chlorite, apatite, and iron-titanium oxide are common accessory minerals. Several specimens contain lenses of slightly different texture which appear to be recrystallized, highly flattened lapilli. A chemical analysis of a quartz latite from Stull Lake is given in Table l, analysis 4.
Metasediments
The metasediments form units that are separated by the felsic to intermediate metavolcanic formations. Three of these units are predominantly pale-coloured volcanic sandstone and volcanic conglomerate that probably reworked pyroclastic deposits; intercalations of cherty greywacke and siltstone are locally present. Satterly (1937b) found three conglomerate units. The most northern and southern units are volcanic conglomerate containing pebbles and boulders of volcanic rocks set in a volcanic sandstone matrix©that is probably reworked tuff. The central unit is a striking boulder conglomerate that is more heterogeneous, containing pebbles and boulders of mafic metavolcanics, granite, dacite, slaty metasedimentsC?) and quartz, in order of decreasing abundance.
Intermediate to Mafic Intrusive Rocks
A large gabbro-diorite stock outcrops along the south shore of Rapson Bay and Gilleran Lake. The intrusion is commonly dark-grey, massive, medium-grained, and intergranular, and has been highly saussuritized and uralitized. The youngest mafic intrusion recognized in the Stull Lake belt is a 200 to 300-foot wide diabase dike. The central part of the dike is medium- grained and massive, and contains equal amounts of plagioclase (An^5 ) and clinopyroxene, with about 5 percent iron-titanium oxide. Uralite, chlorite and epidote are present in minor amounts.
Minor Felsic Intrusions Narrow dikes of quartz-feldspar porphyry intruded the metavolcanics at several localities in the belt. The largest of these is a mile-long dike or sill, at the north end of Stull Lake. In thin section the porphyries are found to range in composition from dacite to quartz latite.
ECONOMIC GEOLOGY
Gold
Satterly (1937b) reported that prospectors were active in the Stull Lake area in 1935 and described five gold showings found by the prospectors. However, only one of these contained economically important amounts of gold. This prospect is located on the south shore of Wynne Bay in a buff- - 23 - coloured metasediment or tuff bed about 6 feet thick. Concordant quartz stringers up to 1/2 inch across in this bed gave assays as high as 1.65 ounces per ton of gold (Satterly, 1937b, p.29). Disseminated pyrite, pyrrhotite and chalcopyrite are also present in the veins. Ten diamond- drill holes, drilled about 1936, failed to intersect any important gold- bearing structures (Satterly, 1937b, p.39-31) Two grab samples collected at this showing during the 1967 field season gave only 0.08 and 0.02 ounces of gold per ton and traces of copper and lead when assayed by the Laboratory Branch of the Ontario Department of Mines. A gold-bearing quartz vein outcrops on an island in the north end of Stull Lake. A report by Rio Tinto Mining Company on file at the Resident Geologist©s office at Red Lake states that surface samples contain up to four ounces of gold per ton. This vein was tested by ten diamond-drill holes put down by Rio Tinto in 1960, but drill logs submitted for assessment work credits show that only very low gold values were intersected. A grab sample of mineralized quartz taken from this vein by Ontario Department of Mines personnel during Operation Lingman Lake yielded 1.86 ounces of gold and 2.36 ounces of silver per ton when analysed by the Laboratory Branch of the Ontario Department of Mines.
Base Metals Phelps Dodge Corporation carried out geophysical surveys over Rapson Bay in 1960. The results of the survey are not available but drill logs submitted for assessment work show that four holes were drilled on the west side of the lake to test electromagnetic conductors. Several sections bearing minor pyrite and pyrrhotite were intersected but, the Company believes 6 to 10-inch sections of graphitic schist have produced the conductors. A one-foot wide gossan zone trending about N600W, was found in an old exploration trench in the southwest end of Rapson Bay. Scattered stringers of pyrite and chalcopyrite about 5 millimetres wide are visible in the zone which occurs in gabbro or diorite. A grab sample collected during the summer of 1967 assayed 0.24 percent copper when analysed by the Laboratory Branch of the Ontario Department of Mines. Satterly (1937b, p.31) reported a narrow fracture zone in metasediments on the south shore of Richardson Arm of Stull Lake about 1/2 mile east of the north-trending diabase dike. The fracture zone is 6 to 12 inches wide and 35 feet long, trends N800W and dips 500 S. The zone contains thin seams, with a maximum thickness of 1/8 inch of sphalerite, chalcopyrite, and pyrite The seams are generally 1/4 to 1/2 inch apart.
MUSKRAT DAM LAKE BELT (Labelled B, Figure 2; O.D.M. P.432, P.433) The Muskrat Dam Lake belt, the closely associated Rottenfish River belt, and much of the surrounding granitic rocks were mapped by L.D. Ayres - 24 -
and assistants during the 1963-1964 field seasons. Preliminary maps P.214 and P.222 (Ayres, 1964) and P.295 (Ayres, 1965) have been issued at a scale of one inch to one half mile. Two geological compilation maps (P.213, P.256) have also been published on a scale of 1:125,000 (Ayres, 1964a, 1964b). An open file report (Ayres, 1966) describing the lithology, stratigraphy, structural geology and economic geology of the Muskrat Dam Lake belt and the Rottenfish River belt is available at the library of the Ontario Department of Mines in Toronto. Another copy of the report is available at the office of the Resident Geologist at Red Lake. A final report is in press.
All information given in this report pertaining to the Muskrat Dam Lake and the Rottenfish River belt as well as the surrounding granitic rocks is taken from the maps and report of Ayres. The reader should consult the publications of L.D. Ayres for further information. The Muskrat Dam Lake belt trends east over a length of at least 65 miles, and ranges in width from 4 to 11 miles. The north-trending Rottenfish River belt is separated from the Muskrat Dam Lake belt by four miles of granitic rocks. It is at least 15 miles long and has an average width of two miles.
Mafic to Intermediate Metavolcanics Mafic to intermediate metavolcanics form about 60 percent of the Muskrat Dam Lake belt, and are by far the predominant type in the eastern half of the belt, they also form most of the Rottenfish River belt. These rocks are mainly basaltic and andesitic flows which have been metamorphosed to greenschist, almandine amphibolite and hornblende hornfels facies. Flow contacts were only rarely observed, but some flows are at least 150 feet thick. Narrow interflow layers of felsic tuff, chert, and iron formation are locally present and aid in the recognition of flow contacts. Most flows are fine-grained except for the central parts of thick flows which are fine- to medium-grained and texturally resemble metagabbro sills. Non-distorted pillows are common in greenschist facies metavolcanics but pillows are generally distorted in the almandine amphibolite facies rocks. Mafic metatuff and metavolcanic breccia are rare but intermediate pyroclastic rocks are locally abundant in the western part of the belt. Gneissic layering is developed in most of the hornblende hornfels facies.
Felsic to Intermediate Metavolcanics
The felsic to intermediate metavolcanics were derived from dacite, rhyodacite, and sodic rhyolite which have been metamorphosed to the greenschist, almandine amphibolite, and rarely to the hornblende hornfels facies. They form 15 percent of the Muskrat Dam Lake belt and are concentrated in the western part of the belt; they form a minor part of the Rottenfish River belt. These rocks range in colour from white to black on the fresh surface but can be distinguished from mafic metavolcanics by their - 25 - low colour index which results in a pale colour on weathered surfaces, and the common occurrence of white mica. In the greenschist and the lower part of the almandine amphibolite facies, fine- to medium-grained plagioclase phenocrysts are preserved in many flows. Felsic pyroclastic rocks are common, and are characterized by rapid vertical and lateral changes in both lithology and composition. Tuffs predominate but pyroclastic breccia and coarse-grained lapillistone are interbedded with the tuff. The tuff locally grades into greywacke which is probably derived from the felsic metavolcanics. In greenschist facies, the primary clastic texture is generally preserved in the metatuffs. Bedding, although absent in many exposures, ranges from thinly laminated to very thick bedded.
Metasediments Metasediments form about 25 percent of the metavolcanic-metasedimentary assemblage of the Muskrat Dam Lake belt but were not found in the Rottenfish Lake belt. Greywacke and siltstone predominate, but minor slate, conglomerate, marble, calc-silicate gneiss and granofels, ferruginous metasediments and iron formation are present. Three types of greywacke and siltstone are found: (1) muscovite- bearing, which are associated with felsic volcanism and appear to be reworked pyroclastic rocks; (2) biotite-bearing which are not genetically associated with felsic volcanism; and (3) amphibole-bearing which are derived from a calcareous sandstone. Slate is most abundant in an 1100-foot thick section along the Severn River at Longitude 92 0 10© where individual slate units are at least 20 feet thick. Beds and lentils of polymictic, pebble metaconglomerate range in thickness from one foot to 1000 feet. The metaconglomerate has a greywacke matrix, and locally contains cobbles and rare boulders. Fragment populations are heterogeneous and vary from unit to unit.
Iron Formation Metamorphosed iron formation consisting predominantly of alternating layers of chert and magnetite were found in the mafic metavolcanics of the Rottenfish River and Muskrat Dam Lake belts. Individual units range in thickness from 2 inches to more than 100 feet. Thickest units are at Munekun Lake (50 feet) and in the northern part of the Rottenfish River belt (30 to 100 feet). Magnetic anomalies on 0.D.M.-G.S.C. aeromagnetic map 3697G suggest that many iron-rich units either do not outcrop or were not found.
The percentage of dark coloured minerals in a rock. - 26 -
Intrusive Rocks
Porphyritic, felsic dikes and sills intruded both the metavolcanic- metasedimentary belts but are rare. They can be subdivided into four types: (1) pre-metagabbro metamorphosed dikes; (2) post-metagabbro metamorphosed dikes; (3) unmetamorphosed felsic dikes associated with granite batholiths; and (4) unmetamorphosed felsic dikes which are not spatially associated with granitic batholiths. Prior to regional metamorphism, sill-like bodies of metagabbro and diorite intruded the volcanic-sedimentary assemblage. These sill-like bodies range in thickness from l foot to 7,800 feet and can be traced laterally for 15 miles. The sills texturally resemble the fine- to medium-grained interiors of thick flows; but are coarser grained. Among the criteria which can be used to distinguish the sills from thick flows are the preservation of primary plagioclase and the lesser degree of recrystallization. The sills have sharp, locally discordant contacts and display narrow chilled zones.
Structural Geology
The Muskrat Dam Lake belt is isoclinally folded and marked facies changes are common. A synclinal axis trends northeasterly through the centre of Muskrat Dam Lake and is truncated by a northwest-trending fault about 8 miles southwest of the lake. West of the fault an east- trending anticline is flanked by two synclines. A syncline trends northwest through Munekun Lake in the east end of the belt. Other fold axes are shown on preliminary map P.256 (Ayres, 1964b). Two main groups of folds were recognized: (1) upright to slightly overturned, isoclinal folds that trend parallel to the axis of the metavolcanic-metasedimentary belt and (2) isoclinal cross folds which trend approximately perpendicular to the first group of folds. The Rottenfish River belt appears to be an isoclinal anticline. Faults were recognized at many places throughout the belt. Most faults are subvertical and have diverse trends, and fault movement ranges from a few inches to many hundreds of feet. Faults which trend north- northwest and north-northeast have the largest amount of movement. The major faults of the Muskrat Dam Lake belt are shown in Figure 2.
ECONOMIC GEOLOGY
There are no known showings of economic importance in the Muskrat Dam Lake belt, although 22 sulphide mineral concentrations and 3 gold-bearing quartz veins are described by Ayres (1966).
Prospectors have been active in the area since at least 1937 and 12 prospectors were in the area during 1963 and 1964. - 27 -
BIG TROUT LAKE - SWAN LAKE BELT
(Labelled K and L, Figure 2, O.D.M. P.427, P.428) This metavolcanic-metasedimentary belt forms the limbs of a great anticlinal(?) fold which extends from Big Trout Lake to the Hanson River, a distance of over 75 miles. The core of the fold consists almost entirely of granitic intrusive rocks, and the limbs, which are rarely more than two miles thick, are surprisingly continuous. The belt consists of about 75 percent mafic to intermediate metavolcanics, 10 percent felsic to intermediate metavolcanics, 10 percent metasediments, and 5 percent mafic intrusive rocks. This belt may continue beyond the Hanson River to join the Stull Lake belt. Such a continuation is suggested by the aeromagnetic data but it could not be verified because this area is covered by the thick glacial deposits of Sachigo moraine. A southern arm of the Big Trout Lake-Swan Lake belt extends from Big Trout Lake to Severn Lake (Labelled L, Figure 2). This arm of the belt consists almost entirely of mafic metavolcanics.
Mafic to Intermediate Metavolcanics
The mafic to intermediate metavolcanics are largely dark-green to black on fresh surfaces and consist of fine-grained to medium-grained, plagioclase (albite to sodic andesine) which lies interstitial to aligned prisms of pale blue-green to green amphibole from 0.1 to 5 millimetres long. Biotite and clinozoisite are locally abundant and quartz, carbonate, leucoxene, iron-titanium oxide, pyrite and apatite are common accessories; chlorite is rare. As much as 10 percent axinite and tourmaline occur in intermediate metavolcanics at the east end of Meston Lake. Medium-grained, massive amphibolite is prominent around the shore of Fat Lake. It was not possible to determine whether this rock is an early gabbroic intrusion, or recrystallized, medium- to coarse-grained basaltic flows. Layered amphibolites are very common in this belt, especially between Big Trout Lake and Severn River. The layering consists of alternating plagioclase-rich and hornblende-rich or rarely epidote-rich layers from a fraction of an inch to more than a foot thick but generally between 1/2 inch to 3 inches thick. In places the layering is well developed and can easily be mistaken for sedimentary bedding. However, the mineralogy and occurrence implies a volcanic origin for these rocks. The principal minerals are plagioclase (oligoclase to andesine), hornblende and epidote, in about the same proportions as massive amphibolites; quartz is present in only accessory or minor amounts. These layered amphibolites tend to occur near the edges of the belt and are associated with undoubted mafic metavolcanics. Ayres (1966, p. 16) described in detail identical layered metavolcanics from the Muskrat Dam Lake belt. Previous mapping of the Big Trout Lake area by Hudec (1964) included much of the layered amphibolite with tuff and greywacke. - 28 -
Migmatite zones are locally developed in the mafic to intermediate metavolcanics, and are most abundant where thin fingers of the belt cross the Severn River. Most of the migmatite consists of lit-par-lit gneiss with amphibolite layers from a few feet to 30 feet thick alternating with granitic layers of similar width.
Felsic to Intermediate Metavolcanics
Felsic to intermediate metavolcanics are best exposed around the shore of Swan Lake. Most of these rocks are fine-grained, pale-grey to dark-grey dacitic flows and tuffs. As in other metasedimentary-metavolcanic belts of the area, pale grey, bedded tuffaceous(?) metasediments are intercalated with the felsic metavolcanics.
A felsic tuff and agglomerate unit about one mile wide and at least 15 miles long occurs within predominantly mafic metavolcanics north of the west shore of Big Trout Lake.
Metasediments
The metasediments of the Big Trout Lake-Swan Lake Belt are largely restricted to the area between Big Trout Lake and the Severn River. Near the Severn River the metasediments are brownish-grey muscovite and biotite greywacke consisting of silt to sand size quartz grains, minor oligoclase and 20 to 35 percent biotite and muscovite. A few thin layers of lean iron formation outcrop on the Severn River. (Iron formation is rare in all metavolcanic-metasedimentary belts of the map-area with the exception of the Sandy Lake belt and the Rottenfish River belt). About six miles east of the Severn River the muscovite greywacke grades into granite-boulder conglomerate which continues eastward for a further 10 miles. The conglomerate consists of cobbles and boulders of white granite, amphibolite, chert, quartz, and felsic metavolcanics in order" of decreasing abundance. A thin section of a specimen from one of the granite boulders indicates that it is a trondhjemite, similar in most respects to the trondhjemites which intrude the belt.
Mafic Intrusive Rocks A gabbroic stock of about 10 square miles in area, is intruded by granitic rocks 16 miles west of Swan Lake, and produces the strongest magnetic anomaly on 0.D.M.-G.S.C. aeromagnetic map 3691G. The stock is not well exposed but seems to consist largely of gabbro and metagabbro and has a well developed ophitic texture. Specimens studied in thin section consisted of tablets of highly saussuritized plagioclase surrounded by uralite pseudomorphs after pyroxene. Magnetite and ilmenite form as much as 10 percent of the rock. A highly saussuritized anorthosite outcrop on the Severn River is presumably part of the stock. A single outcrop of coarse-grained porphyritic gabbro is located at Latitude 50 0 57©, Longitude 90 0 12", northwest of Big Trout Lake. This rock is identical to the gabbroic "leopard rock" described by Hudec (1964) at the east end of Big Trout Lake. - 29 -
A single outcrop of serpentinite is exposed at the east end of Misikeyask Lake about 6 1/2 miles southwest of the porphyritic gabbro described above. The serpentinite body is probably small and appears to have been intruded along a fault. A northwest-trending diabase dike, at least 40 feet wide can be traced on aeromagnetic maps for a distance of about 30 miles and crosses the Big Trout Lake-Swan Lake belt; it is exposed about 10 miles southwest of Swan Lake. The diabase is medium-grained and consists of 50 percent labradorite, 35 percent clinopyroxene, 5-10 percent uralite and 5 percent iron-titanium oxides. Chlorite, quartz, epidote, pyrite and apatite are accessory minerals.
ECONOMIC GEOLOGY
Gold Gold was reported by C.H. Riordon of Conwest Exploration Company in 1946 (J. Satterly, personal communication, 1966). The occurrence is located at the northeast end of Fat Lake near a creek which flows into Jackfish Lake. A detailed description of the showing is not available.
Base Metals and Related Sulphides Hudec (1964, p. 31) reported a mineralized zone at least 30 feet wide and 1000 feet long on the south shore of Derniere Lake about 5 miles southeast of Jackfish Lake. The zone is in brecciated mafic metavolcanics and contains disseminated to massive pyrrhotite and pyrite with minor chalcopyrite. Samples collected for assay by Hudec contained only trace amounts of base metals. Phelps Dodge Corporation of Canada Limited staked this showing in 1962, and the authors observed evidence of "pack sack" diamond drilling on the showing, but the results of the drilling are not known. Several mining companies were active in the Jackfish Lake-Witegoo River area in 1962 (Hudec, 1964) and four holes were drilled by Newconex Limited immediately north of the Witegoo River at Longitude 900 15© and Latitude 54 0 02©. The holes intersected several sections of disseminated pyrite and pyrrhotite with very minor chalcopyrite but assays were very low and no further work was done. A gossan zone was found at about Longitude 91 0 06" and Latitude 54 0 00© during the 1967 field season. The zone trends about N70 0 E and was traced for about 15 feet along the edge of a mafic metavolcanic outcrop and is at least three feet wide. It consists of soft, friable, highly leached metavolcanics carrying blebs of massive pyrrhotite and pyrite with minor chalcopyrite. Two grab samples collected by the senior author were found to contain 0.35 percent and 0.26 percent copper when analysed by the Laboratory Branch of the Ontario Department of Mines. The outcrop occurs on the northwest side of a pronounced northeast-trending valley which may conceal a shear zone or fault. - 30 -
Zinc mineralization is found on the south shore of Southorn Lake near the west end of the lake. Pyrite, pyrrhotite and visible sphalerite, and minor galena occur in a silicified shear zone in epidotized mafic metavolcanics. The mineralized zone is about 20 feet wide and trends N70 0E, for about 80 feet.
A grab sample taken from this showing by Hudec (1964, p. 13) gave an assay of 1.88 percent zinc. A grab sample taken by the authors© assistants and submitted to the Laboratory Branch on assay contained 1.13 percent zinc, 0.21 percent lead and 0.40 oz./ton of silver.
Some trenching had been done on the showing prior to 1967.
No mining companies were active in the Big Trout Lake-Swan Lake belt during the 1967 field season.
BLACKBEAR RIVER - ELLARD LAKE BELT
(Labelled I, Figure 2, O.D.M. P.427, P.428)
This metavolcanic-metasedimentary belt has been traced from about four miles west of the Blackbear River at Latitude 54 0 17© westward to west of Ellard Lake in the west; a distance of at least 55 miles. Anomalies on O.D.M.-G.S.C. aeromagnetic map 3684G indicate that the mafic metavolcanics continue eastward under the Sachigo moraine to the north shore of Echoing Lake. There is no evidence for a connection between this belt and the Stull Lake belt as suggested by Satterly (1937b).
The Blackbear River-Ellard Lake belt consists of about 80 percent mafic metavolcanics, 15 percent felsic metavolcanics, and 5 percent metasediments.
Mafic Metavolcanics and Metagabbro
The mafic metavolcanics of the Blackbear River-Ellard Lake belt are lithologically similar to, and have been metamorphosed to the same grade as those of the Big Trout Lake-Swan Lake belt. Pillow lavas are well exposed at several localities but the pillows are generally highly distorted.
Several outcrops of medium-grained to coarse-grained amphibolite were found near the abandoned mine at Foster Lake. No contacts were exposed and it could not be determined whether the rocks were early metagabbro intrusions or metavolcanic flows. However, the massive structure and even jointing of the rock suggest that it is a metagabbro or metadiorite intrusion.
Felsic Metavolcanics
Felsic metavolcanics are exposed on the shore of Ellard Lake and between Chick and Gummer Lakes. They are mainly pale grey to buff coloured lapillistone and agglomerate which contains 80 percent felsic fragments - 31 - between 1/2 and 2 inches long in a felsic matrix. A specimen of agglomerate from the west shore of Gummer Lake contains minor tourmaline.
Metasediments Lenses of boulder conglomerate from 100 to 1000 feet thick occur about 12 miles west of the eastern end of the belt, immediately south of Sherman Lake and about 4 miles west of Ellard Lake. The conglomerate at all three localities consists of well rounded boulders and cobbles of granite, amphibolite, and felsic metavolcanics, with pebbles of reddish-brown jasper and quartz. The matrix which forms 30 to 50 percent of the conglomerate appears to be greywacke in composition.
Structural Geology The Blackbear Rive .--Ellard Lake belt has a maximum width of only 3 1/2 miles over most o:- its length and appears to be a steeply dipping monocline or tight isoclinal fold. A stock of hybrid granitic rocks intruded the metavolcanics on Ellard Lake and formed a dome-like structure which is either an antiform or a wedged apart conformable sequence.
ECONOMIC GEOLOGY
Gold
The only mineral production from the map-area came from the mine operated by the Sachigo Exploration Company in the Blackbear River-Ellard Lake belt. The following summary is taken from Edwards (1944). Gold was discovered on the south side of Foster Lake in 1935 by Dave Foster and 45 claims were staked to cover the find. This find, the No. l quartz vein, was about 2 1/2 feet wide, trending N300W in metadiorite, and gave average assays of 0.30 ounces of gold per ton; the vein was traced for 450 feet. In 1936 the vein was tested by shallow diamond-drill holes which confirmed the width and gold content determined by trenching. No further work was done on this vein. In the same year assessment work drilling in a muskeg-covered part of the property at the northeast end of Foster Lake, about 1/2 mile north of the No. l vein, resulted in a phenomenal discovery. A two-foot thick section of the first drill hole contained 28 ounces of gold per ton. Further drilling was immediately undertaken on this No. 2 vein, and a 400-foot long zone containing 19,000 tons grading 1.70 ounces of gold per ton was delineated. This zone trends N800W and comprises a number of quartz lenses within mafic metavolcanics. Underground exploration and development commenced in 1937, and between 1937 and 1940 a shaft was sunk to a depth of 1139 feet and 8 levels were established. Mining operations began in 1938 and continued until the mine was closed on the 31st of December, 1941. - 32 -
ODM, MP.27 FIGURE 3
LEGEND
Syenite porphyry SACHIGO RIVER EXPLORATION CO. LTD. ^^B Dacite porphyry
I^H Diorite Right Cross Section Through Shaft
l l Fine-grained mafic lavas 100 200 1^. 4J Coarse-grained mafic lavas Seal t; Feet ( From the Company's Annual Report for 1940) - 33 -
The mine produced 52,560 ounces of gold and 6126 ounces of silver valued at Si,957,054 from 46,457 tons of ore milled. The average grade of the ore was 1.1508 ounces of gold per ton; and net profit was S234,867. The No. 2 zone was concordant to the strike of the enclosing lavas and occurred at this contact between two mafic(?) flows, a northern coarse- grained flow and a southern fine-grained flow. The general dip of the flows is 70 to 75 degrees south but the ore zone was localized in an area where the dips steepened and the flows were vertical or steeply north-dipping. This favourable structural zone was terminated at a depth of about 450 feet. Small lenses and dikes of dacite porphyry (Table l, analysis 6) had been intruded along the contact between the coarse-grained and fine-grained flows and formed the locus for deposition of later quartz veins. The gold occurred in small quartz lenses at the contact between the dacite porphyry and the mafic flows. Dacite porphyry was also found at deeper levels in the mine but was not along the contact and did not contain quartz veins. In addition to gold the veins contained variable amounts of pyrite, sphalerite, pyrrhotite, chalcopyrite, and galena. A second ore shoot was found between 500 and 700 feet but was in a small tuff bed south of the main contact. Gold was present in small quartz veins in the tuff where the dip of the flows was to the north. In 1961 Flint Rock Mines Ltd. restaked much of the original property of the Sachigo River Exploration Company and did geological mapping, ground magnetic and electromagnetic surveys. Twenty-three diamond-drill holes were bored in an attempt to outline ore zones in the No. l vein south of Foster Lake and to find an extension of the No. 2 vein. The report of the consulting geologist and diamond drill logs on file at the Resident Geologist©s office at Red Lake indicated that gold values were generally low, and the claims were allowed to lapse.
Silver A quartz vein between 6 and 8 inches wide at the east end of Lacy Lake was sampled by the authors© assistants and gave an assay of 0.15 ounces of silver per ton when analysed by the Laboratory Branch. The only visible mineralization was a few grains of pyrite and minor limonite staining. The vein trends about easterly in massive mafic metavolcanics.
THORNE RIVER - SACHIGO RIVER BELTS (Labelled H, Figure 2; O.D.M. P.427, P.428) At least three, narrow, closely spaced, essentially east-west-trending belts, which occur between the Thorne and Sachigo Rivers between Latitudes 54 037© and 54 046©, once formed a continuous sequence that had been intruded and subdivided by granitic rocks. The regional aeromagnetic maps 0.D.M.-G.S.C. 3705G suggests that these metavolcanic belts have been truncated at their western end by a major fault or fault zone that trends east-southeast from Yelling Lake to the - 34 -
east edge of the map-area. The western end of one of these belts is bent southward suggesting large scale dragging along this fault; it implies a large left hand horizontal movement along the fault.
These belts consist almost entirely of mafic metavolcanic amphibolite which is generally similar to that in other belts of the region. A few outcrops of dacite were found in the southern part of the most southerly belt but this unit is less than a few hundred feet thick. A thin metasediment unit is reported by the Hanna Mining Company to be present in the most northerly belt, but was not found during the present survey.
ECONOMIC GEOLOGY
Base Metals
The Hanna Mining Company mapped and prospected the greater part of these belts in 1964. Mapping was carried out at a scale of one inch to one mile and copies of these maps are on file at the office of the Resident Geologist at Red Lake.
Two small quartz veins containing pyrite and minor chalcopyrite were located by Hanna Mining Company personnel. The veins are reported to be only a few inches wide and their location is shown onmapsO.D.M. P.427 and P.428. There is no record of activity in the area after 1964.
NORTHERN BELT
(Labelled G, Figure 2; O.D.M. P.427) A small, isolated mafic metavolcanic belt is located at Latitude 54 0 50©, Longitude 91 0 35©. The belt is less than 5 miles long and only 1/2 mile wide but is mentioned here because of its anomalous north-northeast trend. All other belts in the area trend east or east-southeast. The northern part of the belt is displaced about one mile westward along a west-northwest trending fault. The southern portion of the belt is folded eastward around a metagabbro and metadiorite stock. Schistosity in the southern part of the belt has relatively gentle dips, as low as 20 degrees and are the lowest dips recorded in the map-area. The rocks of this belt are mainly layered, mafic to intermediate amphibolites which appear to be derived from volcanic rocks. In places the amphibolites are highly migmatized and embayed by hybrid granitic dikes and sills. - 35 -
ECONOMIC GEOLOGY
Base Metals and Related Sulphides Hanna Mining Company Limited also prospected and mapped this small belt in 1964, and found one narrow quartz vein containing pyrite and chalcopyrite. The vein is located on geological maps of the Company which are on file at the office of the Resident Geologist at Red Lake. No claims were staked and there is no record of activity in the area since 1964.
AZURE LAKE BELT
(Labelled P, Figure 2; O.D.M. P.430) A narrow belt of metavolcanics and metasediments extends eastward from Azure Lake near the Manitoba-Ontario boundary for a distance of about 24 miles. Both ends of this belt extend beyond the map-area, but the belt is known to be part of the Favourable Lake belt mapped by Hurst (1929) south of the map-area (L.D. Ayres, 1968, personal communication). At Azure Lake the belt is one mile wide and the rocks on the north shore of the lake are predominantly grey to brownish-grey greywacke. At least three highly carbonatized and silicified shear zones ranging in width from a few feet to ten feet are exposed on the shore of the lake and indicate the presence of faults sub-parallel to the strike of the greywacke. The only mafic metavolcanics found in the belt are north of Azure Lake. East of Azure Lake the belt narrows to less than 2000 feet before widening to four miles south of Varveclay Lake. The edges of the belt are poorly defined because extensive migmatite zones have made contacts irregular and gradational. The migmatite is composed of fine- to medium- grained, biotite-hornblende-quartz schist and gneiss which were intruded by granitic dikes and sills. It is only in the few places where conglomerate beds are preserved that the sedimentary origin of the rocks can be determined. Recent mapping by L.D. Ayres and assistants at the southeastern end of Azure Lake belt indicates that the belt may be considerably wider than indicated on O.D.M. map P.430 (Averill and Ayres, 1968, p. 8).
ECONOMIC GEOLOGY
Silver and Lead In 1952 Orlac Red Lake Mines Ltd. optioned a lead-silver occurrence near Gorman Creek about six miles southeast of Varveclay Lake. A report in the Northern Miner, (31 January, 1952) stated that the occurrence assayed 16 to 26 percent lead, 20 ounces per ton of silver and 0.24 ounces per ton - 36 -
of gold across a width of five feet; it is apparent that these values could not have continued over any great distance because the property was subsequently dropped. There is no record of diamond drilling.
Several unsuccessful attempts were made to locate this showing during the 1967 field season.
SAGAWITCHEWAN BELT (Labelled T, Figure 2; O.D.M. P.431) The Sagawitchewan belt is the narrow eastern end of the Island Lake belt of Manitoba. The northern side of the Sagawitchewan belt consists of mafic metavolcanics which are in part layered amphibolite. Beds of intermediate agglomerate up to 50 feet thick are locally present within the metavolcanic unit. The southern part of the belt is predominantly pale-grey quartzite and dark-grey greywacke and minor amounts of conglomerate which contains highly stretched granitic boulders.
ECONOMIC GEOLOGY
Gold From 1937 to 1952 Sagawana Gold Mines Limited held a 45-claim property near Sagawitchewan Falls, but the exact location is unclear (Northern Mines Handbooks 1937, 1938, 1943 to 1947, 1952). Reports in the Globe and Mail, 8th January, 1946 and in Precambrian, October 1945 state that three shear zones were uncovered, the longest of which is 1,200 feet long and 20 feet wide. Samples from this zone are said to average more than 0.5 oz. gold per ton and to contain copper, silver, lead, zinc and tungsten. There is no record of diamond drilling or assessment work. The Company©s charter was cancelled in 1954.
WITEGOO RIVER BELT (Labelled J, Figure 2; O.D.M. P.429, P.428) The Witegoo River belt was traced from Latitude 54 0 00©N, Longitude 89 0 31© westward to the Severn River. The belt is poorly exposed and seems to consist almost entirely of foliated mafic metavolcanics and derived amphibolite. Highly sheared and stretched pillow lavas were found at one locality. At its western end on the Severn River the belt is split into four narrow fingers of lit-par-lit migmatite and amphibolite by granitic intrusions. - 37 -
ECONOMIC GEOLOGY
There are no known economic mineral occurrences in the Witegoo River belt. Grab samples were collected from two small quartz veins on the Severn River but gave nil values in gold and silver when assayed by the Laboratory Branch.
OTHER METAVOLCANIC BELTS
(Labelled Q, R, U, O, M, N, Figure 2; O.D.M. P.430 to P.434) These six belts are poorly exposed and appear to consist entirely of mafic metavolcanics. There are no known economic mineral occurrences in these belts.
INTERMEDIATE INTRUSIVE ROCKS Intermediate intrusive rocks of diorite and quartz diorite composition form isolated stocks within the granitic batholiths and marginal zones adjacent to some of the metavolcanic-metasedimentary belts. The major bodies are described below. A hornblende diorite stock about 16 square miles in area (labelled S, Figure 2) is well exposed near the Manitoba-Ontario boundary about 20 miles north of Angekum Lake and is well defined on 0.D.M.-G.S.C. aeromagnetic map 3656G. The essential minerals are plagioclase (An32.4o)* dark-green hornblende and locally biotite,while quartz, clinozoisite, apatite, zircon and chlorite are present in minor amounts. The iron-titanium content is estimated to be 4 percent. The diorite is older than at least some of the surrounding granitic rocks because pink and grey granitic dikes were found to intrude the diorite. A few outcrops of medium-grained, massive, grey diorite were found about 15 miles south-southeast of Lingman Lake. This diorite has little or no magnetic expression on aeromagnetic maps and probably was formed by contamination of granitic rocks. About l 1/2 miles northeast of Jackfish Lake a pronounced U-shaped aeromagnetic anomaly with a maximum dimension of three miles appears on 0.D.M.-G.S.C. aeromagnetic map 3762G. Outcrops are sparse in the area of the anomaly but three mafic granitic outcrops and one metagabbro outcrop were found near the edges of the anomaly. The medium-grained, massive, mafic granitic rock which was called diorite and quartz diorite on map P.428 was found on thin section examination to be an oligoclase trondhjemite containing about 2 to 20 percent biotite, 5 to 20 percent hornblende and O to 2 percent iron-titanium oxides. The metagabbro consists of about 80 - 38 - percent uralite and 20 percent highly saussuritized plagioclase. The shape and profile of the anomaly suggests that the mafic granitic rocks found are the edges of a mafic diorite or gabbro stock. A slightly larger oval anomaly of comparable magnitude occurs about five miles east of Jackfish Lake. The more gentle profile of the anomaly suggests that it may reflect a pluton of similar composition which did not reach the present bedrock surface. The only outcrops found in this anomalous area were white leucogranite. Eight bodies of medium-grained to cparse-grained quartz diorite, leucodiorite and diorite occur adjacent to the major metavolcanic- metasedimentary belts in the northeast quarter of the map and are either the earliest stage of granitic intrusion or a contaminated marginal facies of the granitic batholiths. The dioritic rocks are characterized by a dull grey, deeply pitted, weathered surface and extreme toughness. Specimens studied in thin section consist of 60 to 70 percent plagioclase (.^28-40^ 10 to 30 percent hornblende, 5 to 10 percent biotite and O to 15 percent quart z.
GRANITIC BATHOLITHS The granitic batholiths underlie about 80 percent of the map-area and are intrusive into and separate the metavolcanic-metasedimentary belts. Except for several small areas such as Ellard Lake and south of Swan Lake (Figure 2) individual plutons or batholiths could not be defined during the reconnaissance survey. Several phases or rock types were recognized in the batholiths but their areal distribution could not be delineated. Although the batholiths were not sampled in a systematic manner, it is tentatively concluded that the most widely distributed and abundant granitic rock type in the entire area is medium-grained, equigranular, hornblende or biotite trondhjemite. The trondhjemite is either massive, foliated or gneissic and is typically mottled light grey and black on fresh surfaces. Pink trondhjemite is locally found and the pink colour results from the alteration of the plagioclase feldspar. The principal minerals are plagioclase (An5,2o) * quartz, coarsely prismatic hornblende and biotite. The second most abundant granitic rock type is medium-grained equigranular, grey to pink quartz monzonite which is either massive, foliated or less commonly gneissic. Plagioclase (AnQ,^), microcline and quartz are the major felsic minerals. Biotite is the predominant mafic mineral but hornblende-bearing quartz monzonite is present in minor amounts Porphyritic quartz monzonite occurs along the northern edge of the Sachigo River-Thorne River, belt and between the Witegoo and Fawn Rivers (Table l, analysis 7); the phenocyrsts are microcline perthite. It was generally found from cross -cutting relationships that the quartz monzonite is younger than the trondhjemite. However, more detailed mapping by L. D. Ayres in the Muskrat Dam Lake area and in the Trout Lakes area immediately south of Sandy Lake has shown that there are many granitic intrusive units in the batholiths that have the general age sequence - 39 -
(oldest first) quartz diorite, trondhjemite, granodiorite, quartz monzonite, granite, pegmatite, but there are several reversals in this trend (Ayres, 1966; 1968). Aplite and granite pegmatite dikes are widespread but are not abundant in most parts of the map-area. Most of these dikes are less than 10 feet wide and are of simple biotite-quartz-albite-microcline types.
Hybrid Granitic Rocks About 20 percent of the granitic rocks within the area of Operation Lingman Lake are probably hybrid types. In general these are intermediate to felsic, medium-grained, intrusive rocks which contain clots, schlieren, or unusually high (20 percent) concentrations of mafic minerals (usually biotite) along with such secondary minerals as epidote and sericite. The texture is typically inhomogeneous reflecting incomplete mixing of magmas or of magmas and country rock.
Migmatite Migmatite zones consisting of lit-par-lit granitic sills and mafic layers, or high concentrations of mafic schlieren and inclusions are common around the edges of the metavolcanic -metasedimentary belts, particularly in the eastern half of the map-area. Wide zones of migmatite, covering areas of up to 15 square miles in area are occasionally found several miles from major metavolcanic- metasedimentary belts. These migmatite zones are generally revealed on aeromagnetic maps as areas of magnetic intensity higher than that of the surrounding granitic rocks.
Syenitic Rocks Quartz-bearing monzonite (1-5 percent quartz) occurs at several localities on Finger Lake (Map P.431) and about six miles north-northeast of the Sachigo River Mine (Map P.427). These occurrences appear to be local quartz-poor facies of the granitic batholiths. Undoubtedly other small syenite bodies exist, but were not found because of the reconnaissance mapping methods employed. A poorly exposed stock of calc-alkalic hornblende syenite, hornblende quartz monzonite and granite underlies an area from about 16 to 25 square miles immediately east of the small metavolcanic-metasedimentary belt labelled G on Figure 2. The rocks are medium-grained, equigranular and massive to foliated and display a characteristic mottled pink and black colour. The syenite contains about 45 percent perthitic microcline, 10 percent sodic andesine, 40 percent green hornblende and minor amounts of chlorite, iron-titanium oxides, apatite and zircon. The granite and quartz monzonite contain about 15 percent quartz and have more oligoclase and less hornblende than the syenite. The abundance of microcline which has unusually broad twin lamellae, and hornblende makes this rock distinct from the surrounding granitic rocks. No crosscutting relationships were observed, - 40 -
and as a result the relative age of the syenite is unknown. However, it could be related to the Carb Lake Carbonatite, nine miles to the west.
A small stock of porphyritic monzonite is exposed along the Severn River at the west end of Fawn River-Severn River metavolcanic-metasedimentary belt. The monzonite contains closely packed phenocrysts of microcline microperthite up to 10 millimetres across set in a fine-grained groundmass of oligoclase and green and brown biotite (Table l, analysis 8).
CARB LAKE CARBONATITE (Labelled F, Figure 2; O.D.M. P.426, P.427) The publication of O.D.M.-G.S.C. aeromagnetic maps 3685G and 3693G revealed a circular magnetic anomaly at Latitude 54 0 47©, Longitude 92 0 00". While investigating the area of this anomaly in the summer of 1967, geologists of M.J. Boylen Engineering Ltd., discovered boulders of carbonatite and alkalic rocks on the shore of a small lake which has since been unofficially named Carb Lake. Forty-four claims were staked for Big Nama Creek Mines Limited and Larandona Mines Limited and these companies had a combined airborne magnetometer and gamma-ray spectrometer survey made of the property in September 1967. The survey outlined a highly magnetic and slightly radioactive body of l 1/2 miles in diameter (Figure 4) No outcrop occurs on the claims but four 400- to 500-foot long diamond drill holes were put down during the winter of 1967-68. The drilling substantiated the presence of carbonatite but was insufficient to delineate major rock units. Fifteen samples of the drill core were examined in thin section and eighteen specimens were submitted to the Laboratory Branch for trace- element analysis (Table 2) and X-ray diffraction analysis. Due to difficulties encountered in spectrographic analysis of rocks with wide variations in composition the spectrographic trace-element analyses were restricted to the carbonate fraction of carbonate-rich samples and to carbonate-poor samples. Examination of drill core and thin sections indicated that the dominant rock type encountered in drilling is a pale pink to grey or white carbonate containing scattered books of reddish-brown biotite or phlogopite, scattered grains of magnetite, wisps of fibrous amphibole, and lenses of apatite grains. In thin sections the carbonate forms about 80 percent of the carbonatite and is a granular mosaic of about equal amounts of dolomite and calcite, although in any given samples either dolomite or calcite usually predominates. The phlogopite is pale brown in thin section but has a red titaniferous(?) rim. Pale coloured to colourless apatite ranges from less than l to 25 percent and forms individual prisms in carbonate and monomineralic lenses up to an inch long composed of elliptical grains. The amphibole is bluish-green to blue and is believed to be eckermannite and sodic actinolite. - 41 -
FIGURE 4
Magnetic contour (gammas) Diamond drill hole
AEROMAGNETIC MAP OF THE CARB LAKE CARBONATITE
ODM.MP.27 Data From Assessment Files - 42 -
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J^ 0 0 O 0 0 O 0 O LO O o o 0 O 0 O M LO O 0 0 0 0 O LO rH O LO * * \o O 0 rH CQ rH rt CM LO to to rH Tt to CM rH
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** 6 O O rH o rH CD rt * * * * * * * * * * * * * * * -K o H - PH E- o rH O O W D- C P rt rH W rH rt o o 0 0 0 0 o o 0 0 O o\0 o\0 O o o LO H CQ PH rH o o o o o o 0 0 o o O rH rH O 0 0 5 CO O LO LO O LO O O CM o o 0 * * 0 O LO Z X C tO CM CM f-^ CM CM Tt rH CM CM Tt * * Tt Tt CM O rH -H CQ O Od -P C ^ rt O 0 0 0 0 0 0 0 0 0 O 0 0 O 0 O 0 CJ rH 'H rz^p LO O 00 O LO O 0 0 o O LO c^ t*** o o rt 0 P rH 0 CM i—t CM 0 0 * 0 CM rH O CM pu .0 rt LO tO rH Tt rH O rt rH rJ P CO C W X CD o o 0 0 o o o o 0 0 0 0 0 O 0 0 o co ,o o c 0 0 o o 0 0 0 O o o 0 O o o o o 1—1 ^•H g s O 0 LO O LO O LO O O LO o o 0 0 o o •J w o Tt LO rH LO Tt Tt CM t^ ^O CM CM CM tO CM Tt LO ^ CD U o:Z xw rH 0 O 0 0 0 O o 0 O O o\0 o\0 O o 0 u rt rt O 0 o o o o 0 0 O O rH rH O o o rH C J LO LO to o rH Tt Tt * CM 00 o * * to Tt * rH x -3 rH CM * * (X
g O 0 o o 0 o 0 oXo oXO o\0 O O 0 o Q CD o o 0 0 o o o rH LO LO O O 0 o PH CJ OO O 0 0 * 00 0 * * o * * * 0 0 0 LO fn CM rH LO rH to * * * rH rH CM u PJ OH o o o o 0 0 O o\0 o o\0 O o o o o 0 rt LO O o o O LO LO rH o rH O 0 0 O LO LO CQ CM 00 tO CM LO rH \O "Jt •K O * LO LO LO Tt rH rH x rH 1—1 4c rH * rH rH *"C3 rH CD CD p p* o rt CD 6 •P -H CD X tp C f"O O LO 0 0 rH CM * •H •P PH CD o rH tO 00 LO LO r^ t^ o 00 o r^- oo V) p 0 PH CD rH CM Tt CM rH rH Tt \0 rH vO O Tt NO r^ LO 00 O rH P O C rt rH PH ' 00 CM tO CM CM CM CM tO tO CM Tt rH rH r^ Tt Tt CD -H CD o 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 S 6 P 1 1 rt rt Z rH rH rH CM CM CM CM CM CM tO Tt Tt Tt Tt Tt CM O -H CD H CO x x x x x x x x x x x x x x x x J J Q * * - 43 -
Sections of core up to 60 feet long were found to consist almost entirely of medium- to coarse-grained biotite or phlogopite with scattered grains, clots or stringers of magnetite and seams of amphibole. Sections up to 55 feet long consist predominantly of magnetite with subordinate silicates and carbonate. All variations between carbonatite, magnetite- rich and biotite-rich rocks exist.
At several places a colour layering was observed in the carbonate and it appears to be parallel to the contacts between the various rock types. The angle between the core axis and the layering suggests a vertical layering or zoning within the carbonatite.
Many sections of the core are "vuggy" suggesting leaching of the carbonate by acid solutions.
The following is a summary of the less common minerals identified by X-ray diffraction or thin section:
Pyrite: Pyrite is the only sulphide identified. It rarely exceeds a few percent, even over narrow widths, and is generally found as disseminated grains or coarse blebs within or near vuggy sections.
Hematite: Hematite occurs locally as a fine red dust in carbonate and as patches of deep red earthy material. It is most common in vuggy areas and appears to be due to the oxidation of pyrite.
Vermiculite: Deep green vermiculite occurs in cavities and vugs and is probably due to the hydrothermal alteration or weathering of pre-existing micas
Pyrochlore: Pale yellow to deep brown, zoned octahedrons of pyrochlore formed from 3 to 5 percent in two thin sections; a few grains were noted in three other specimens.
Synchysite (Ce,La,Ca)FCOg: This rare mineral forms irregular soft pinkish patches or veinlets in carbonatite. It is associated with fluorite and is probably of late hydrothermal origin. In thin section synchysite forms pale-brown scaly masses.
Ancylite (Ce,La)4(Sr,Ga)3(CQg)7(OH)45H20: This is another rare earth-bearing mineral of which only a few occurrences are known. It was identified in a sample taken from a boulder on the shore of a small lake overlying the carbonatite. Ancylite forms deep red clots about 1/2 inch across a carbonatite: in thin section it is orange in colour but is too fine-grained for optical properties to be determined. Spectrographic analysis indicated a cerium content of 2 percent and a lanthanum content of l percent for part of the rock specimen. Fluorite; Purple fluorite occurs in "vuggy" sections in association with synchysite, pyrite and hematite. In thin section it forms a mosaic of anhedral grains enclosing partly replaced grains of carbonate, prisms of apatite and wisps of synchysite. - 44 -
PLEISTOCENE GEOLOGY
During the Pleistocene, the area was covered by several ice sheets, but, except for isolated occurrences, all glacial features were formed by the youngest sheet. Two lobes of this ice sheet affected the area, an older eastern lobe and a younger western lobe. The lobes were separated by the Sachigo interlobate moraine, a north-trending ridge that is the major topographic feature of the map-area.
Direction of Ice Movement
East of the Sachigo interlobate moraine the predominant direction of glacial striae is southwest, although local variations occur (Figure 5); southeast of Muskrat Dam Lake they trend west-southwest (Ayres, 1966). The gently sloping northeastern end and the steeply sloping southwestern of most roches moutonees indicate that the last movement of glacial ice was in a southwesterly direction.
Drumlins and drumlinoid ridges are common between Whithers Lake and Misikeyask Lake and in the Muskrat Dam Lake area, and commonly trend between S40 0W and S55 0W, parallel to the glacial striae.
Hudec (1964) and Tyrrell (1913) found glacial striae near Big Trout Lake that indicated an earlier direction of ice movement from southeast to northwest. Old striae of similar trend were also found near Muskrat Dam Lake but the direction of ice movement could not be determined (Ayres, 1966),
West of the Sachigo moraine most glacial striae trend south or south- southwest, but on Stull Lake older southwest-trending striae were also observed. Derry and MacKenzie (1931) also observed both sets of striae on the west side of the Sachigo Moraine and concluded that the south-southeast- trending striae are younger. The older southwest-trending striae are parallel to, and probably comparable in age to those on the east side of the moraine, and indicate that at one time a southwest-moving ice lobe covered the entire area. A resurgence of the glacier caused a south-moving lobe of ice to re-cover the westernmost part of the area. The Sachigo interlobate moraine probably represents both the eastern edge of the younger lobe and the western edge of the stagnant older lobe.
Moraines
Ayres (1966, p. 66) described a low end moraine extending from north of Sachigo Lake southwestward to Makoop Lake. The moraine has a local relief of about 50 feet and a maximum width of about 3500 feet. Several eskers are terminated against the north side of the moraine and Ayres also states that there is evidence of modification by wave action.
A second moraine forms the highest hills in the map-area and extends southward from near Red Cross Lake in Manitoba (Potter, 1962), along the east side of Kistigan Lake in Manitoba, between Echoing and Stull Lakes, to within a few miles of Sandy Lake, a distance of about 130 miles (Figure 5). The moraine is generally 150 to 300 feet higher than the adjacent bedrock and ranges in width from about 2000 feet to eight miles. Well - 45 -
developed beach deposits are found on the sides of the moraine and extend almost to the top; they indicate that at one time most of the moraine was submerged beneath the waters of a glacial lake. Satterly (1937a, 1938) noted the difference in the direction of the glacial striae on either side of the moraine and concluded that it was an interlobate moraine formed between two stagnant lobes of ice. As mentioned in the previous section the authors believe that the western lobe was younger than the eastern one. Another prominent moraine occurs about 20 miles north of Sandy Lake and trends westward to beyond the Ontario-Manitoba boundary (Figure 5). Elson (1961) included this moraine as part of the Sachigo interlobate moraine, but Ayres (1966) concluded that it is an end moraine marking the furthest advance of the western lobe of ice. The authors have named this the Opasquia end moraine.
Eskers
The eskers are relatively continuous ridges of sand and gravel that are generally less than 40 feet high. The distribution of eskers is shown in Figure 5. The convergence of several eskers indicates that the subglacial streams generally flowed toward the southwest. The general lack of eskers west of Sakwaso Lake and south of Opasquia end moraine (Figure 5) reflects the destruction of eskers by wave action of the glacial lake which occupied this area and to their burial beneath lake sediments. Eskers could not be identified on aerial photographs northeast of a line extending from Misikeyask Lake to the south end of Rieder Lake. Their absence could be due to (1) wave modification and burial by glacial lake sediments or (2) modification by the Tyrrell Sea marine embayment, a Pleistocene embayment of Hudson Bay (Lee, 1960). The first alternative is unlikely because no deposits of glacial lake sediments were found in this area. Near Rieder Lake the northern limit of eskers approximately corresponds with the southern limit of the Tyrrell Sea given by Prest et al. (1968) but near Misikeyask Lake the assumed edge of the sea is 35 miles north of the most northern esker.
Glaciolacustrine Deposits A belt of thick varved clay deposits extends from the Manitoba-Ontario boundary eastward along the valley of the Cobham River and through Sandy Lake. Ayres (1966) reported that thick deposits of varved clay and wave- modified eskers do not occur east of the Windigo River, or north of Sandhill Crane Island in the Severn River west of Muskrat Dam Lake. These thick varved clay deposits and wave modification of eskers indicate that a relatively long-lived glacial lake occupied this area as the ice retreated northward. Ayres (1966) located the north-trending eastern edge of a major glacial lake near the Windigo River; he also noted that the present elevation of beach deposits on the Opasquia and Sachigo moraines indicate that the lake must have been at least 200 feet deep during - 46 -
950 94 0 93 0 55 550
Figure 5
OPERATION LINGMAN LAKE PLEISTOCENE FEATURES
LEGEND
Moraines
Glacial striae
54
95o"© ODM.MP.27 940 920 - 47 -
920
530 -530 - 48 -
one of its stages.
Satterly (1937a, 1938) mapped varved clays on both sides of the Sachigo interlobate moraine on Ponask Lake and Sachigo Lake, and was able to show by correlation of varves that contemporaneous glacial lakes, which he named Glacial Lakes Ponask and Sachigo, existed on both sides of the moraine. Varved clay deposits on Kistigan and Rourke Lakes indicate that these glacial lakes may have extended as far north as the Ontario-Manitoba boundary.
Elson (1967) concluded that the Sandy Lake basin formed part of the later stages of Lake Agassiz but that Glacial Lake Sachigo may have been separated from the main body of Lake Agassiz when the water level dropped below the altitude of the divide at the west end of the Cobham River watershed. However, beach deposits on the lower levels of the Sachigo interlobate moraine can be traced from about eight miles north of Sandy Lake to west of Sachigo Lake and there is no marked topographic divide between Sandy Lake and Sachigo. The authors therefore suggest that if Glacial Lake Sachigo was separated from Lake Agassiz, which extended into the Sandy Lake basin, the separation must have occurred during the late stages of the glacial lake when the water level was very low. Following the breakup of the ice sheet in Hudson Bay the northern end of Glacial Lake Sachigo was opened and the lake drained in a series of stages through such rivers as the Echoing and the Sachigo. Elson (1967) suggested a date between 7500 and 8000 years before the present for the event.
RECOMMENDATIONS FOR FUTURE EXPLORATION
Airborne geophysical surveys with ground follow-up surveys and diamond drilling of anomalies is probably the most effective method of exploration for this area; but where the metavolcanic - metasedimentary belts are narrow such a survey would be relatively costly. As of February 1969, only the Lingman Lake and Ponask Lake belts are known to have been completely covered by airborne geophysical surveys. Other areas may have been surveyed, but if no claims were staked, no data would be submitted for assessment work credits. Although most of the metavolcanic-metasedimentary belts have been explored by prospectors since the 1930©s, it is worth noting that most of this prospecting was oriented towards precious metals. The traditional methods of prospecting are still worthwhile in most of the metavolcanic- metasedimentary belts, and especially those which are relatively unexplored, such as the part of the Big Trout Lake - Swan Lake belt between Blackbear Lake and the Severn River. A copper occurrence about 16 miles east of Blackbear Lake may be worth a more detailed examination. The exact location of the former gold property which is reported to be near Sagawitchewan Falls in the Sagawitchewan belt could probably be found with some detailed prospecting and deserves attention. The proximity of the Carb Lake Carbonatite to what appears to be a major east-southeast to southeast-trending fault zone is of interest. Other - 49 -
carbonatite bodies with much lower magnetic expression may lie within or adjacent to the zone, but might be sufficiently radioactive to be located by a gamma ray spectrometer survey. A paper by Ayres et al. (1969) discusses the distribution of deposits of economic metals in northwestern Ontario. Ayres et al. conclude that there is evidence for the association of uranium, silver and lead deposits with south-southeast- to southeast-trending faults. There is also an apparent association of gold deposits with felsic metavolcanics. The information presented in the paper of Ayres et al. should be of interest to anyone who is undertaking mineral exploratTbn~~in northwestern Ontario. - 50 -
REFERENCES CITED
Averill, S.A. and Ayres, L.D. 1968: Favourable Lake - Poplar Hill area, District of Kenora (Patricia Portion); in Summary of Field Work, 1968; Edited by E.G. Pye, Ontario Dept. Mines, Miscellaneous Paper 22, p.6-10.
Ayres, L.D. 1966: Geology of the Muskrat Dam Lake area, District of Kenora (Patricia Portion); Ontario Dept. Mines.Open File Report 5002, 102 p.
1969: Geology of the Muskrat Dam Lake area, District of Kenora (Patricia Portion); Ontario Dept. Mines,Geol. Rept. 74 (in press).
Ayres, L.D., Bennett, G. and Riley, R.A. 1969: Geology and mineral possibilities in northern Patricia district, Ontario; Ontario Dept. Mines, Miscellaneous Paper 28.
Derry, D.R. and MacKenzie, G.S. 1931: Geology of the Ontario-Manitoba boundary (12th Base Line to Latitude 54); Ontario Dept. Mines, Vol.XL, pt.2, 1931, p.1-20. Downie, D.L. 1938: Stull Lake Sheet (East Half), Manitoba and Ontario. Geological map with marginal notes; Geol. Surv. Canada, map 451A.
Edwards, B.C. 1944: Developing and operating a mine on the Canadian tundra; Canadian Mining Jour., March, p.135-146; April, p.214-227; May, p.300-312; June, p.380-396; July, p.467-478.
1.1 son, J.A. 1967: Geology of Glacial Lake Agassiz; in Life, Land and Water, Mayer-Oakes,W.J. (ed.), (Proceedings of the 1966 Conference on environmental studies of the Glacial Lake Agassiz region) University of Manitoba Press, Winnipeg, p.37-95.
Hudec, P.P. 1964: Geology of the Big Trout Lake area, District of Kenora (Patricia Portion); Ontario Dept. Mines, Geol. Rept. 23, 35 p.
Hurst, M.E. 1929: Geology of the area between Favourable Lake and Sandy Lake, District of Kenora (Patricia Portion); Ontario Dept. Mines, Vol.XXXVIII, pt.2, 1929, p.49-84 (published 1930).
Lee, H.A. 1960 Late glacial and post-glacial Hudson Bay sea episodes; Science, Vol.131, No.3413, p.1609-1611.
Low, A.P. 1887: Preliminary report on an exploration of country between Lake Winnipeg and Hudson Bay; Geol. Surv. Canada, Ann. Rept., Vol.11, pt.F, 24 p. (p.8-19 reprinted in Ontario Bur. Mines, Vol.XXI, pt.2, 1912, p.94-106; route maps, which were not part of the original report, were added to the reprint). - 51 -
Meen, V.B. 1937: Geology of the Sachigo River area; Ontario Dept. Mines, Vol.XLVI, pt.4, 1937, p.32-59 (published 1938). Potter, R.R. 1962: Gods River map-area, Manitoba; Geol. Surv. Canada, Paper 62-8.
Quinn, H.A. 1960: Island Lake, Manitoba-Ontario, Sheet 53E, Geological map with marginal notes, Geol. Surv. Canada, Map 26-1960.
Sanford, B.V., Norris, A.W., and Bostock, H.H. 1968: Geology of the Hudson Bay Lowlands (Operation Winisk); Geol. Surv. Canada, Paper 67-60, p. 1-45. Satterly, J. 1937a: Glacial Lakes Ponask and Sachigo, District of Kenora (Patricia Portion), Ontario; Jour. Geol., Vol.45, p.790-796. 1937b: Geology of the Stull Lake area; Ontario Dept. Mines, Vol.XLVI, pt.4, 1937, p.1-31 (published 1938). 1938: Geology of the Sandy Lake area; Ontario Dept. Mines, Vol.XLVII, pt.7, 1938, p.1-43 (published 1939). 1939: Geology of the Windigo-North Caribou Lakes area; Ontario Dept. Mines, Vol.XLVIII, pt.9, 1939, 32 p. (published 1941). Tyrrell, J.B. 1913: Hudson Bay exploring expedition, 1912; Ontario Bur. Mines, Vol.XXII, pt.l, 1913, p.161-209.
MAPS
Ontario Department of Mines Maps P.213 Muskrat Dam Lake Area (53 F/E 1/4, 52 G/W 1/2), District of Kenora (Patricia Portion). Geological compilation, structural geology, and sulphide occurrences. Includes Index Map showing preliminary maps, P.214-P.222. Scale 1:125,000. By L.D. Ayres and assistants, 1963 (issued 1964). P.214 Fox River Area (53 F/l, 53 F/8), District of Kenora (Patricia Portion). Scale, l inch to 1/2 mile. By L.D. Ayres and assistants, 1963, 1964. (Revised, issued 1965. This map bore the title "Martyn River Area" until the 1965 revision). P.215 Gruneau Lake Area (53 F/8, 53 G/5) , District of Kenora (Patricia Portion). Scale, l inch to 1/2 mile. Geology by L.D. Ayres and assistants, 1963 (issued 1964). - 52 -
Maps P.216 Kippen Lake Area (53 F/l, 53 F/8, 53 G/4, 53 G/5), District of Kenora (Patricia Portion). Scale, l inch to 1/2 mile. By L.D. Ayres and assistants, 1963 (issued 1964). P.217 Muskrat Dam Lake Area (53 G/5, 53 G/6, 53 G/ll, 53 G/12). District of Kenora (Patricia Portion). Scale, l inch to 1/2 mile. By L.D. Ayres and assistants, 1963 (issued 1964). P.218 Hillis Lake Area (53 G/3, 53 G/4, 53 G/5, 53 G/6), District of Kenora (Patricia Portion). Scale, l inch to 1/2 mile. By L.D. Ayres and assistants, 1963 (issued 1964). P.219 Munekun Lake Area (53 G/6, 53 G/ll), District of Kenora (Patricia Portion). Scale, l inch to 1/2 mile. By L.D. Ayres and assistants, 1963 (issued 1964). P.220 Cooney Lake Area (53 G/6), District of Kenora (Patricia Portion). Scale, l inch to 1/2 mile. Geology by L.D. Ayres and assistants, 1963 (issued 1964). P.221 Misquamaebin Lake Area (53 G/6, 53 G/7, 53 G/10, 53 G/ll), District of Kenora (Patricia Portion). Scale, l inch to 1/2 mile. By L.D. Ayres and assistants, 1963 (issued 1964).
P.222 Pike Lake Area (53 G/2, 53 G/3, 53 G/6, 53 G/7), District of Kenora (Patricia Portion). Scale, l inch to 1/2 mile. Geology by L.D. Ayres and assistants, 1963 (issued 1964). P.256 Muskrat Dam Lake Area (53 F/E 1/4, 53 G/W 1/2), District of Kenora (Patricia Portion). Scale, 1:125,000. Geology by L.D. Ayres and assistants, 1963, 1964 (issued 1964).
P.295 Rottenfish River Area (53 F/l, F/2, F/7, F/8, F/9), District of Kenora (Patricia Portion). Scale, l inch to 1/2 mile. Geology by L.D. Ayres and assistants, 1964 (issued 1965).
Operation Lingman Lake Maps P.426 Stull Lake Sheet P.431 Finger Lake Sheet P.427 Swan Lake Sheet P.432 Rottenfish River Sheet P.428 Blackbear River Sheet P.433 Muskrat Dam Lake Sheet P.429 Witegoo River Sheet P.434 Makoop Lake Sheet P.430 Varveclay Lake Sheet Scale l inch to 2 miles. Geology by G. Bennett, R.A. Riley, L.D Ayres, J.C. Davies and assistants, 1967 (issued 1967). Index map on page 2 of this report. Geological Survey of Canada Maps 451A Stull Lake (East Half), Manitoba and Ontario. Scale l inch to 4 miles. Geology by D.L. Downie and maps of the Ontario Department of Mines (issued in 1938). 26-1960 Island Lake, Manitoba-Ontario. Scale l inch to 4 miles. Geology by H.A. Quinn and assistants (issued in 1960).