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Ontario Geological Survey Miscellaneous Paper 89
Preliminary Geological Synthesis of the Savant Lake-Crow Lake Metavolcanic-Metasedimentary Belt Northwestern Ontario and Its Bearing upon Mineral Exploration
by N.F. Trowell, C.E. Blackburn and G.R. Edwards
1980
Ministry of Hon- James A- c. Auld Minister Natural ^ , ^ 0 Dr. J. K. Reynolds ReSOUrCeS Deputy Minister Ontario OMNR-OGS1980 Printed in Canada
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ISSN 0704-2752 ISBN 0-7743-4876-3
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Trowell, N.F., Blackburn, C.E. and Edwards, G.R. 1980: Preliminary Synthesis of the Savant Lake Crow Lake Metavol- canic-Metasedimentary Belt, Northwestern Ontario, and Its Bearing upon Mineral Exploration; Ontario Geological Survey, Miscellaneous Paper 89, 30p. Accompanied by Chart A.
1000-300-80-Sp. ii Contents
Abstract...... v Tables Introduction ...... 1 Geological Setting ...... 1 1 Tentative time correlation of rock-stratigraphic sequences, Savant Lake Sub-Area ...... 2 Savant Lake-Crow Lake area ...... 8 Sturgeon Lake Sub-Area...... ©...... 3 2 Base metal sulphide deposits in the Sturgeon Lake .area ..19 Sioux Lookout Sub-Area ...... 3 3 Base metal sulphide occurrences in the Savant Lake Area 20 Wabigoon-Manitou Lakes Sub-Area ...... 5 Kakagi-Atikwa Lakes Sub-Area ...... 6 General Stratigraphic Relationships ...... 7 Figures Preliminary Geochemical Synthesis ...... 10 Correlation of Geochemistry with Stratigraphy ...... 12 Regional ...... 12 1 Location of the Savant Lake Crow Lake area ...... v Local ...... 14 2 Broad lithostratigraphic relationships in the Savant Approach to a Tectonic Model ...... 16 Lake Crow Lake area ...... 9 Mineral Deposits ...... 18 3 Classification of subalkalic volcanic rocks by Jensen Cation Gold ...... 18 Plot involving the cation percentages of AI203, Savant Lake Sub-Area ...... 18 FeO + Fe2O3 -i- TiO2 , and Mgd ...... 10 Sturgeon Lake Sub-Area ...... 18 4 Jensen Cation Plot comparing the patterns of variation of ko- Sioux Lookout Sub-Area ...... 18 matiitic, tholeiitic, and calc-alkalic rock suites ...... 10 Wabigoon-Manitou Lakes Sub-Area ...... 18 5 Cation plots for Jutten Volcanics, Northern Volcanic Belt, and Kakagi-Atikwa Lakes Sub-Area ...... 19 Wapageisi Volcanics ...... 11 Base Metals ...... 19 6 Cation plots for Rowan Lake, Kakagi Lake, Lower Wabigoon Volcanogenic Base Metal Sulphides ...... 19 Volcanics, Manitou Section, North and South Sturgeon Lake Sturgeon Lake Sub-Area ...... 19 Volcanics, Handy Lake Volcanics, and Beckington Road and Savant Lake Sub-Area...... 20 Morgan Island Sections of the Northeast Arm Volcanics ...12 Sioux Lookout Sub-Area...... 21 7 Cation plots for Brooks Lake, Katimiagamak, Boyer Lake, Wabigoon-Manitou Lakes Sub-Area ...... 21 Upper Wabigoon and Central Sturgeon Lake Volcanics ...14 Kakagi-Atikwa Lakes Sub-Area ...... 21 8 Composite cation plots for 1191 Samples, Savant Lake-Crow Copper and Molybdenum Deposits Associated with Sub Lake area ...... 15 volcanic and Granitoid Plutons ...... 22 9 Distribution of the three volcanic suites ...... 15 Savant Lake Sub-Area ...... 22 10 Chemical variation along a section through tholeiitic to calc- Sturgeon Lake Sub-Area ...... 22 alkaline flows and pyroclastics (TCFP) and overlying Fe-tho- Sioux Lookout Sub-Area ...... 22 leiitic flows (FTF) at Wabigoon Lake ...... 16 Kakagi-Atikwa Lakes and Wabigoon-Manitou Lakes 11 Cross-section illustrating hypothetical stage of develop Sub-Areas ...... 22 ment during the time of late tholeiitic to calc-alkaline flow Copper and Nickel in Mafic and Ultramafic Intrusions and and pyroclastic volcanism (TCFP) ...... 17 Flows ...... 22 Savant Lake Sub-Area ...... 22 Sturgeon Lake Sub-Area ...... 23 Chart Sioux Lookout Sub-Area...... 23 Wabigoon-Manitou Lakes and Kakagi-Atikwa Lakes (Back pocket) Sub-Areas ...... 23 A Preliminary stratigraphic units and structural geology, Sa Uranium and Other Lithophile Elements...... 23 vant Lake-Crow Lake metavolcanic-metasedimentary belt, Discussion of Mineralization and Exploration Guidelines ...... 24 Districts of Kenora, Rainy River, and Thunder Bay. Volcanogenic Base Metal Deposits ...... 24 Volcanogenic Copper-Gold Deposits ...... 24 Gold Deposits ...... 24 Copper-Molybdenum Deposits ...... 25 Copper-Gold in Intrusive Rocks ...... 25 Platinum and Platinoid Group Elements ...... 25 References...... 25
Ill Conversion Factors for Measurements in Ontario Geological Survey Publications If the reader wishes to convert imperial units to SI (metric) units or SI units to imperial units the following multipliers should be used:
CONVERSION FROM SI TO IMPERIAL CONVERSION FROM IMPERIAL TO SI SI Unit Multiplied by Gives Imperial Unit Multiplied by Gives
LENGTH 1 mm 0.039 37 inches 1 inch 25.4 mm 1 cm 0.393 70 inches 1 inch 2.54 cm 1 m 3.280 84 feet 1 foot 0.3048 m 1 m 0.049 709 7 chains 1 chain 20.1168 m 1 km 0.621 371 miles (statute) 1 mile (statute) 1.609344 km
AREA 1 cm2 0.1550 square inches 1 square inch 6.4516 cm2 1 m2 10.7639 square feet 1 square foot 0.09290304 m2 1 km2 0.38610 square miles 1 square mile 2.589988 km2 1 ha 2.471 054 acres 1 acre 0.404 685 6 ha VOLUME 1 cm3 0.061 02 cubic inches 1 cubic inch 16.387064 cm3 1 m3 35.3147 cubic feet 1 cubic foot 0.02831685 m3 1 m3 1 .308 0 cubic yards 1 cubic yard 0.764555 m3 CAPACITY 1 L 1.759755 pints 1 pint 0.568261 L 1 L 0.879877 quarts 1 quart 1.136522 L 1 L 0.219969 gallons 1 gallon 4.546 090 L MASS ig 0.03527396 ounces (avdp) 1 ounce(avdp) 28.349 523 g 19 0.03215075 ounces (troy) 1 ounce (troy) 31.1034768 g 1kg 2.204 62 pounds (avdp) 1 pound (avdp) 0.453 592 37 kg 1kg 0.001 1023 tons (short) 1 ton (short) 907.18474 kg 1 1 1.102311 tons (short) 1 ton (short) 0.90718474 t 1kg 0.00098421 tons (long) 1 ton (long) 1016.0469088 kg 1 1 0.984 206 5 tons (long) 1 ton (long) 1.0160469088 t CONCENTRATION 19/t 0.0291666 ounce (troy)/ 1 ounce (troy)/ 34.2857142 g/t ton (short) ton (short) ig/t 0.583 333 33 pennyweights/ 1 pennyweight/ 1.7142857 g/t ton (short) ton (short)
OTHER USEFUL CONVERSION FACTORS 1 ounce (troyyton (short) 20.0 pennyweights/ton (short) 1 pennyweight/ton (short) 0.05 ounce (troyVton (short)
NOTE Conversion factors which are in bold type are exact. The conversion factors have been taken from or have been derived from factors given in the Metric Practice Guide for the Canadian Mining and Metallurgical Industries published by The Mining Association of Canada in coop eration with the Coal Association of Canada.
IV Abstract The Savant Lake-Crow Lake metavolcanic-metasedimen- Petrochemical variation diagrams show that the up tary belt extends for 300 km within the western part of the ward progression from thick basal mafic sequences to Wabigoon Subprovince. Its geologic setting is described mixed mafic to felsic sequences is paralleled by a pro by referring to five sub-areas: Savant Lake, Sturgeon gression from magnesian tholeiitic basalt to mixed tholei Lake, Sioux Lookout, Wabigoon-Manitou Lakes, and Ka- itic to calc-alkalic basalt to rhyolite. Thick mafic assem kagi-Atikwa Lakes. Preliminary correlation of stratigraphy blages within or above the mixed sequences are iron-rich is made between these sub-areas based on the following tholeiitic basalt. The mixed sequences are locally cycli observations: 1) general inward facing of metavolcanic- cal. Tectonic evidence is not inconsistent with a model metasedimentary sequences; 2) thick basal mafic as based on plate-tectonic theory. semblages are all situated at the outer edges of the belt; Selected individual deposits of gold, base metals, 3) overlying, mixed mafic to felsic sequences are more in copper and molybdenum, copper and nickel, and ura ternal and contain thick assemblages of mafic flows that nium are discussed with reference to their lithologic and are mostly toward or at the top of these sequences, and stratigraphic setting in the five sub-areas. A discussion of in some places may be allochthonous; 4) association of potential for mineralization, and exploration guidelines, clastic sedimentary rocks with mixed mafic to felsic por are given for volcanogenic base metal and copper-gold tions of volcanic sequences; and 5) lateral continuity of deposits, gold deposits, copper-molybdenum deposits, copper-gold in intrusions, and platinum and platinoid certain ironstone-bearing formations. group elements.
PALEOZOIC MESOZOIC PRECAMBRIAN
PROTEROZOIC
Granitic Rocks Supracrustal
irkland Scolc of Miles Lake 0 50 100 1SO
Figure 1 Location of Savant Lake-Crow Lake area and its position within the Superior Province.
Preliminary Geological Synthesis of the Savant Lake Crow Lake Metavolcanic-Metasedimentary Belt, Northwestern Ontario, and Its Bearing Upon Mineral Exploration by N.F. Trowell1, C.E. Blackburn1 and G.R. Edwards2
history of the Savant Lake-Crow Lake belt. Stratigraphic Introduction correlation and evolutionary trends in petrochemistry and Considerable geologic mapping has been carried out by depositional environments were to be elucidated, with the Ontario Government in the Early Precambrian meta- particular consideration being given to the place of min volcanic-metasedimentary belts of northwestern Ontario eral concentrating processes. The secondary objective commencing in the latter years of the last century. Until was td assess where future detailed mapping should be the 1940s, early work in the Savant Lake Crow Lake belt concentrated, so as to aid both future regional geological (Figure 1), was of a reconnaissance nature (1 inch to 1 re-interpretations and exploration. mile and greater). Emphasis subsequently shifted to de The field program involved, over the 1977 and 1978 tailed mapping (1 inch to V* mile and smaller). Of neces seasons, a rapid re-assessment of previous mapping sity, this tended to be of patchy distribution, located in throughout the belt (Trowell et al. 1977, 1978), and the areas of known interest to prospectors and exploration. In completion of geochemical sampling of all the major se more recent years Ontario Government geologists have quences. The present authors have recently completed embarked on longer-term detailed mapping programs in extended studies in the Sturgeon Lake area (Trowell specific portions of the belt but these too have tended to 1970, 1974a,b, 1976, 1977, in prep), the Manitou Lakes be considered in isolation one from each other. area (Blackburn 1976a, 1979a,c, in prep), and the Kakagi In recent years geological knowledge has advanced Lake vicinity (Edwards 1976,1978, in prep) during which and concepts have changed at an accelerating rate. much of the stratigraphic synthesis and geochemical Much of the earlier detailed mapping, excellent and com sampling was initiated. prehensive in its time, must now be considered to be in The present report has evolved from two oral presen need of revision and update. This is especially so be tations, one in March of 1978 when preliminary strati cause it is increasingly being understood that exploration graphic appraisal and place of mineral deposition was for economic mineral deposits is facilitated by a sound given at a workshop of the Ontario Geological Survey and knowledge of the depositional and intrusive environments another (Blackburn et al. 1978) giving a preliminary ap to which the minerals are related. For example, the Zn- praisal of geochemical information related to stratigra Cu-Ag-Pb deposits at Sturgeon Lake have been shown phy. The present report is intended as an interim report (Franklin 1975, 1976, 1977; Franklin et al. 1973, 1975, on this ongoing project. Final results are to be published 1977; Trowell 1974a,b, 1976, in prep) to be genetically as an Ontario Geological Survey Study. related to volcanic processes in a distinctive, cyclical, en vironment. With these limitations in mind a program was com menced in 1976 to synthesize and reassess the available geological mapping throughout the belt. The objectives were twofold. The primary objective was to determine, as Geological Setting far as the available information would allow, the geologic The 300 km long Savant Lake Crow Lake metavolcan- ic-metasedimentary belt is situated at the western end of the Wabigoon Subprovince or Belt (Mackasey et al. 1974). It is continuous with similar lithologies further west 1 Geologist, Precambrian Geology Section, Ontario Geological Survey, Toronto. at Lake of the Woods and to the south at Rainy Lake 2 Graduate Student, University of Western Ontario, London. through to Lac des Milles Lacs. As pointed out by Macka Manuscript approved for publication by the Chief Geologist, On sey et al. (1974), the metavolcanic-metasedimentary as tario Geological Survey, Aug. 15, 1979. Published with the per semblages of the Wabigoon Subprovince show a pro mission of E.G. Pye, Director, Ontario Geological Survey. nounced northeast alignment, confined to two broad SAVANT LAKE—CROW LAKE northeasterly trending lithologic zones now separated by Jutten Volcanics can be traced to the west and south as a large area underlain by granitic rocks. The present area far as Kimmewin Lake within the Miniss River Fault zone under discussion is confined to the more northwesterly of (Breaks and Bond 1977). these two lithologic zones (Figure 1). Polymictic clast- to matrix-supported conglomerate In a previous comprehensive study, Goodwin (1965, overlies the Jutten Volcanics. The contact is a major ero 1970) recognised lithologic continuity along part of the sional and angular unconformity (Skinner 1969; Bond belt under discussion, and suggested, by implication, its 1979; Shegelski and Bell 1976; Shegelski 1978). Ero stratigraphic continuity. For purposes of the present dis sional surfaces and angular discordance between the cussion it is convenient to divide the belt into sub-areas Jutten Volcanics and the conglomerate are present. within which there is a good degree of understanding of Granitoid clasts in the conglomerate are locally similar in stratigraphy and structure. As will become evident, corre lithology to nearby granitoid plutons that intrude the Jut lation between these sub-areas is less well established. ten Volcanics (Funk 1973; Kusmirski 1977), indicating Names of preliminary stratigraphic units and struc that the Jutten Volcanics were intruded and deformed by tural features used in the text are shown on Chart A (back the granitoid plutons prior to deposition of the conglomer pocket). Stratigraphic terminology is not formalized ac ate. cording to the requirements of the current code of strati North and west of Savant Lake, in the Neverfreeze graphic nomenclature (American Commission on Strati Lake area and the Kashaweogama Lake area, the con graphic Nomenclature 1970). glomerate, locally grading upward to wacke and siltstone (Shegelski 1978) passes laterally along strike into inter mediate pyroclastics, some of which are subaerial, and mafic flows (Bond 1977, 1979; Shegelski and Bell 1976; Savant Lake Sub-Area Shegelski 1978). The conglomerate thins to the west though it can be traced to the north end of Kimmewin A series of mafic metavolcanic flows, the Jutten Volcanics Lake (Breaks and Bond 1977). (Rittenhouse 1936) comprise the northwest and south- Similar conglomerate with finer clastic sediments oc east margins of the Savant Lake part of the volcano-sedi curs along the south shore of Savant Lake and in the Nev mentary belt. On the southeast side of Savant Lake an erfreeze and Elwood Lakes area, though here they were approximately northwest-facing homoclinal sequence is likely deposited in a more restricted lobe of an originally locally interrupted by minor folding. The sequence has an continuous sedimentary basin (Sutcliffe in Trowell etal. apparent maximum thickness in excess of 9 km, possibly 1977). Two epizonal porphyry stocks that intrude the met up to 11 km. The Jutten Volcanics thin to the south, even asediments at Neverfreeze and Elwood Lakes could rep tually disappearing apparently due to intrusion of the Jut resent subvolcanic equivalents of pyroclastics interca ten Batholith along the plane of unconformity between the lated within the conglomerate. volcanic rocks and overlying conglomerate. The north Volcanism that began with the eruption of pyroclas west sequence of Jutten Volcanics forms a broad east- tics intercalated within the conglomerate continued with trending synclinal structure (Breaks and Bond 1979). The the formation and deposition of the Handy Lake Volcan stratigraphically lowest exposed portion of the Jutten Vol ics (Rittenhouse 1936) comprising a complexly interca canics is exposed in the area of Armit Lake (Sutcliffe in lated sequence of mafic metavolcanics, intermediate and Trowell et al. 1977). Interbedded chert and magnetite, felsic pyroclastics and redeposited volcanic fragmentals, locally sulphidic, ironstone1 is situated near the base of subvolcanic intrusions with comagmatic effusive phases, this sequence. In the Neverfreeze Lake area, to the east, and wacke-siltstone with thin interbeds of quartz iron a correlative band of chemical metasediments is found in silicate-magnetite ironstone. direct intrusive contact with granitic rocks (Sutcliffe in In the Hough-Houghton Lakes area the fragmentals Trowell etal. 1977). appear to be of pyroclastic origin whereas to the east and In the Armit Lake area ultramafic sills (Hudec 1965; south they are redeposited fragmentals with intercalated Sutcliffe in Trowell et al. 1977) attain thicknesses of 120 clastic metasediments (Trowell 1978). In central Savant m. Locally associated with the ultramafic rocks is a rock Township pillowed and amygdaloidal mafic metavolcan composed primarily of diopside and a zone of recrystal- ics conformably overlie the conglomerate. A serpentin- lized sediments or pyroclastics. ized peridotite, possibly a flow, conformably lies near the Trusler (1975) reported that remnants of the Jutten base of these metavolcanics. Volcanics including ultramafic rocks, occur as enclaves The turbiditic wacke-siltstone within the Handy Lake within granitic rocks west of Armit Lake. Remnants of the Volcanics indicates that sedimentation also continued and that subsequent degradation of the Handy Lake Vol canics is reflected by the overlying, in part correlative, wacke-siltstone of the Savant Sediments (Bond 1979; 1 The term ironstone is used here as defined in the unpublished Shegelski 1978). classification manual of the Ontario Geological Survey, issued The Savant Sediments comprise fine arenaceous to 1978: a chemical sedimentary rock that contains 33 percent or argillaceous clastic metasediments deposited by turbid more of the common iron minerals by volume. This definition ex cludes other chemically precipitated sediments such as chert, ity currents (Bond 1979; Shegelski 1978) with interbed and clastic sedimentary material, that are commonly interlayered ded magnetite ironstone formed as chemical precipitates with ironstone. of iron and silica originating from a volcanic source (She of lower units or are correlatives of the Central Sturgeon gelski 1978). Lake Volcanics that overlie both the North and South Stur geon Lake Volcanics. The Central Sturgeon Lake Volcanics comprise pil lowed and amygdaloidal flows and autoclastic units. Mi Sturgeon Lake Sub-Area nor intermediate flows and fragmentals locally comprise the top of the sequence. Ultramafic and mafic intrusions At Sturgeon Lake volcanic sequences are folded about are situated between lower flows and upper fragmental east-, northeast- and northwest-trending axes. units. A lower, north-facing, mixed sequence south of Stur The Sturgeon Narrows Structural Zone transects the geon Lake, the South Sturgeon Lake Volcanics, has been Sturgeon Lake volcano-sedimentary belt. The zone is shown by recent mapping (Trowell in prep) to be com probably an early structure, along which later rifting oc posed of four volcanic cycles. Each cycle consists of a curred, associated with emplacement of the Sturgeon lower unit of mafic metavolcanics and an upper unit of in Narrows and Squaw Lake alkaline complexes that intrude termediate to felsic fragmentals. Clastic metasediments the volcano-sedimentary belt. Late movement along this occur locally between cycles. Franklin et al. (1977) con zone is indicated by breccia, shear, and mylonite zones. sider the South Sturgeon Lake Volcanics to comprise only three volcanic cycles, each cycle comprising a lower unit of mafic metavolcanics, an overlying unit of intermediate Sioux Lookout Sub-Area and felsic fragmentals and an upper unit of metasedi ments. The massive base-metal sulphide deposits of the The volcano-sedimentary belt between Sioux Lookout Sturgeon Lake camp are situated within felsic fragmen and Wabigoon Lake is composed of five major lithostrati tals near the tops of the lower two cycles of Trowell (in graphic units. Except for assigning the Patara Sediments prep) or top of the lowermost cycle of Franklin et al. of Pettijohn (1934,1935) to potential group status (Trowell (1977). in Trowell et al. 1978) due to the wide diversity of litholo- Laterally extensive mafic metavolcanic flows form gies found within it, the terminology of Turner and Walker the base of the South Sturgeon Lake Volcanics. Massive (1973) is followed for naming these lithostratigraphic flows predominate but rare, finely amygdaloidal and mi units. nor porphyritic flows are also present. Pillowed flows and The Northern Volcanic Belt comprises a lower, pre autoclastic/pyroclastic fragmentals occur at the top of dominantly south-facing mafic metavolcanic sequence this lower sequence. The flow structures and textures in herein named the Botham Bay Volcanics (not labelled on dicate initial deep water outpourings of mafic lava build Chart A) and an upper mixed intermediate to felsic meta- ing up a broad basaltic (shield) volcano. volcanic-metasedimentary sequence, the Patara group. Upwards, cyclic volcanism dominates. Mafic flows Flow structures and texures such as vesicularity and are massive and pillowed and show an upward increase pillow form were initially the parameters used to subdi in vesicularity. Intermediate to felsic fragmentals, with vide the Botham Bay Volcanics. Subsequently, whole- rare felsic flows, are predominantly of redeposited pyroc rock chemical analyses of samples collected during the lastic and rarely autoclastic breccia origin. Upper frag present study indicate that these subdivisions are in gen mental units show evidence of having formed by explo eral a reflection of their chemistry: either high-magnesian sive volcanism in a shallow water to subaerial flows (rounded to amoeboid-shaped pillows, non-amyg- environment. Shales, graphitic shales, and sulphidic daloidal) which predominate, or high-iron flows (bun- (graphitic) ironstones are situated within or overlie upper shaped pillows, large amygdules) respectively. Recum felsic fragmental units. A major unit of laterally extensive, bent-style folding has repeated portions of the Botham north-facing, clastic metasediments tops the South Stur Bay Volcanics at Vermilion Lake. High-iron tholeiitic meta geon Lake Volcanics. volcanic flows have locally been thrust faulted into their The character of this mixed sequence is akin to se present observed position between high-magnesian quences developed in modern-day island-arc stratovol- flows. canoes. An interbedded chert and quartz-magnetite (locally North of Sturgeon Lake, the predominantly south- sulphidic) ironstone unit is locally found at the top of the facing North Sturgeon Lake Volcanics likewise show a Botham Bay Volcanics. Clasts of similar lithology to this cyclical development of volcanic stratigraphy. White unit are found in the unconformably overlying conglomer comprising the north limb of the Sturgeon Lake syncline, ate of the Patara group (Johnston 1972; Trowell in Trowell this volcanic sequence is not strictly correlative, either li- efa/. 1978). thologically or chemically, to the South Sturgeon Lake The Patara group has three main components: (1) Volcanics of the south limb (Trowell in prep.). clastic metasediments of volcanic derivation; (2) interme To the northeast, the North Sturgeon Lake Volcanics diate to felsic pyroclastics, redeposited volcanic frag are correlative with the lower half of the Northeast Arm mentals, and derived conglomerate; and (3) quartz por- Volcanics. Further to the north, distal tuffaceous units of phyry/felsite hypabyssal subvolcanic rocks (Johnston the Northeast Arm Volcanics interfinger with similar units 1972; Trowell in Trowell et al. 1978). On the basis of the of the Handy Lake Volcanics. Upper volcanic units of the distribution and interrelationship of these three lithologies Northeast Arm Volcanics either represent fold repetitions it appears that volcanism was contemporaneous with the SAVANT LAKE—CROW LAKE deposition of the upper clastic metasediments of the Pa- vast amounts of andesitic material and in the unique tara group and continued during and following deposition chemistry of the andesites themselves (Page 1978a). of the Ament Bay Formation (Turner and Walker 1973) of Quartz-feldspar porphyry/felsite and trondhjemite the Abram Group (Trowell /ntrowell etal. 1978). With this plutons of probable subvolcanic origin intrude the Central proviso of concomitant volcanism and sedimentation the Volcanic Belt. They are similar in texture and composition stratigraphic subdivision of the Abram Group by Turner to intrusions within the Patara group described above and Walker (1973) is still applicable with respect to the though no time equivalence has been established. description of lithologies and is followed in this paper. In the eastern portion of the area the Central Volcanic The Abram Group comprises the Ament Bay, Dare Belt appears to be fault-bounded against both the Abram devil, and Little Vermilion Formations (Turner and Walker and Minnitaki Groups. To the southwest actual contact re 1973; Trowell in Trowell etal. 1978). The Ament Bay For lationships are not known but faulting, possibly with a mation is composed of granitoid-clast conglomerate and thrust component, is suspected. arkose. It exhibits an unconformable to locally conforma The Minnitaki Group is predominantly composed of ble relationship to the underlying Patara group. Distribu wacke-siltstone, arkose, and granitoid-clast conglomer tion of lithologies and observed sedimentary structures ate. The granitoid clasts are predominantly quartz-felds indicate a change in the environment of deposition from par porphyritic trondhjemite and equigranular trondhjem subaerial alluvial fan deposition (Turner and Walker 1973) ite and were likely derived by erosion of hypabyssal to possibly braided river deposition (Trowell in Trowell et subvolcanic intrusions and unroofing of-subjacent grani al. 1978). toid rocks. The conglomerates are mainly confined to the The Daredevil Formation appears to be both interca area of East Bay, Minnitaki Lake and continue only a short lated with and overlying the Ament Bay Formation. It is distance to the east (Page 1978b). They have been inter composed predominantly of intermediate to felsic tuff preted as proximal turbidites of the resedimented associ with minor mafic tuff and wacke-siltstone at Little Vermi ation (Walker and Pettijohn 1971). To the southwest finer lion Lake. grained wacke-siltstones are of the deep water turbidite The Little Vermilion Formation overlies the Ament Bay association. and Daredevil Formations. It is composed of sediment- Whether the Minnitaki Group is the folded equivalent clast conglomerate and wacke-siltstone likely deposited of the Abram Group as Johnston (1972) suggested or by turbidity currents. Its interpreted environment of depo whether it is a younger clastic metasedimentary se sition is in marked contrast to that of the Ament Bay For quence as suggested by Turner and Walker (1973) has mation beinq more akin to that of the Minnitaki Group (see not been resolved. below). The metavolcanic sequences in Pickerel Township The Abram Group faces predominantly south with could be intercalated within rather than infolded (John minor reversals. The Little Vermilion synclinal fold and its ston 1969) with the Minnitaki Group metasediments. eastern extension are faulted out along the Little Vermi To the southwest in the vicinity of Dryden, metasedi lion Fault. An outcrop of sediment-clast conglomerate oc ments laterally equivalent to the Minnitaki Group are curs along the north shore of the west portion of Abram bounded to the south by the Wabigoon Fault. Similarly in Lake. It could be the lateral correlative or the fault-dis the area of Southeast Bay, Minnitaki Lake the Minnitaki placed equivalent of the similar unit at Little Vermilion Group is in fault contact with the Southern Volcanic Belt. Lake. Silicate-quartz-magnetite ironstone is interbedded There are places however where the boundary of the Min with thickly bedded graded wacke units at the east end of nitaki Group and Southern Volcanic Belt are irregular and Abram Lake, and possibly continues northeast along the not obviously fault controlled (P. Palonen, Geologist, On length of Botsford Lake (Page 1978b). tario Ministry of Natural Resources, personal communica The Central Volcanic Belt is composed dominantly of tion 1978). Splay faults with a thrust or strike component metavolcanics with minor wacke and siltstone of volcanic off the main fault could account for these local irregulari provenance. In the eastern portion of the area a felsic me- ties. tavolcanic sequence exposed at Superior Junction and The Southern Volcanic Belt lies along strike from, extending to the northeast (Page 1978b) and southwest and appears to be correlative in part with, the Central (Johnston 1972) apparently lies at the base of the Central Sturgeon Lake Volcanics, the youngest volcanic assem Volcanic Belt. It is composed of felsic pyroclastic and au blage in the Sturgeon Lake area. Here andesite and ba toclastic breccia, possible flows, subvolcanic intrusive salt flows and fragmentals overlie the mafic flows in the material and minor mafic flows. area between Flying Loon Lake and Whiterock Lake. It is A broad laterally extensive assemblage of mafic possible that these andesites and basalts are correlative flows (Page 1978a; Trowell in Trowell etal. 1978) overlies with the sequence of similar composition within the Cen this basal sequence. Thin interflow beds of intermediate tral Volcanic Belt. If so, the Southern Volcanic Belt may to felsic tuff and wacke units of volcanic provenance be, in part, correlative to the mafic flow sequence under characterize this assemblage. lying the andesites of the Central Volcanic Belt. Interme An assemblage of mafic to intermediate flows and diate volcanic flows are also present in the general South- fragmentals of basalt and andesite composition overlie east Bay, Minnitaki Lake area (Bartlett in Trowell et al. the lower mafic flow sequence. This assemblage may be 1978). unique to the Savant Lake Crow Lake area both in the A zone of dominantly intermediate to felsic pyroclas- tics occupies the northeast region of Southeast Bay, Min- Lake in the west to beyond Wapageisi Lake in the east. nitaki Lake (Bartlett in Trowell era/. 1978) and extends an The name Wapageisi Volcanics is here applied to this se unknown distance to the east. It is composed of lithic tuff, quence. Correlation has been made between these vol heterolithic tuff-breccia and minor crystal tuff. canic rocks and the lowermost sequence of mafic flows Ultramafic and mafic intrusions occur in the lower northwest of the Manitou Straits Fault on lithologic, chemi portion of the Southern Volcanic Belt (Bartlett in Trowell et cal, and structural grounds (Blackburn 1976b, in prep). al. 1978; Palonen and Speed 1977; P. Palonen, personal The Wapageisi Volcanics are overlain by a predomi communication 1978). nantly clastic sequence. West of Taylor Lake this has In the southwest part of the area the Southern Vol been named the Manitou Group (Teal and Walker 1977). canic Belt is predominantly northwest facing. Folding oc Recent mapping (Blackburn 1976a, 1979a; Teal and curring in the vicinity of Southeast Bay, Minnitaki Lake Walker 1977) has shown the group to be composed of a (Bartlett in Trowell et al. 1978) was also noted by Pettijohn lower pyroclastic sequence and an upper epiclastic se (1937) in the eastern extention of the lake. quence. Teal and Walker (1977) have documented pas sage upward from terrestrial to submarine epiclastic fa cies. Northwest of the Manitou Straits Fault, pyroclastics of proximal facies at Upper Manitou Lake have been cor Wabigoon-Manitou Lakes Sub-Area related (Blackburn 1976b) with volcanic rocks of the Manitou Group. At the east end of the clastic sequence, At Eagle and Wabigoon Lakes, volcanic sequences are abundant magnetite ironstone is intercalated within sand essentially north facing, as was recognized by Moor stone of probable distal turbidite facies at Bending Lake. house (1941) and Satterly (1943). However, at Eagle Felsic intrusions into the lower, Wapageisi Volcanics, are Lake, the lower part of these Wabigoon Volcanics (Sat subvolcanic phases of some of the more felsic volcanism terly 1943) are folded about three northeast-trending in the clastic sequence and may be comagmatic with axes, and the top of the sequence is folded about a num phases of the Irene-Eltrut Lakes Batholithic Complex ber of tight east-trending folds close to its northern (Blackburn in prep). Granitoid clasts in conglomerates faulted contact (Blackburn in Trowell et al. 1977, Black (Thomson 1934; Blackburn 1976a, 1979a; Teal and burn 1979b). Walker 1977) of the Manitou Group suggest unroofing of At Wabigoon Lake the lower part of the sequence is subjacent batholiths. composed of pillowed mafic flows intercalated within a The name Boyer Lake Volcanics is given here to a heterogeneous assemblage of tuff and lapilli-tuff pyroc thick sequence of pillowed mafic flows that lie structurally lastics and volcanic-clast metasediments. At Eagle Lake above the Manitou Group. The Boyer Lake Volcanics are the stratigraphically equivalent lower part of the se intruded by a number of synvolcanic gabbroic sill-like quence is predominantly composed of pillowed mafic bodies. Recent investigations (Blackburn in Trowell et al. flows. Mafic and ultramafic intrusions occur at the base of 1977, 1978) suggest that the Boyer Lake Volcanics are the lower sequence at Mile Lake and at Nabish Creek. limited to the north and east by pyroclastic rocks at Ka Felsic pyroclastics and flows appear to be concentrated washegamuk Lake and south of Melgund Township. They toward the top of the lower sequence, notably near cen are bounded in the northwest (Blackburn 1979a) by the tral Eagle Lake and central Wabigoon Lake. Recent field Manitou Straits Fault. Directly across the fault, volcanic investigations (this study) show that subvolcanic felsic sequences that lie conformably above the pyroclastics of phases near Meridian Bay of Eagle Lake pass gradation- Upper Manitou Lake are lithologically akin to and continu ally into granitic phases of the Atikwa Batholith with which ous with Wabigoon Volcanics, and therefore cannot be they are therefore genetically related. Similar relation correlated with Boyer Lake Volcanics. ships may be present between rhyolites just east of Con Satterly©s (1943, 1960) mapping in the vicinity of tact Bay and rocks of the batholith at Contact Bay of Wa Southworth, Satterly, and Melgund Townships indicates bigoon Lake. the structural complexity of this area. Lack of detailed At both Eagle and Wabigoon Lakes the lower se mapping in Avery and MacFie Townships prevents corre quence is overlain apparently without a break by a pre lation at the present time of this structurally complex area dominantly pillowed mafic flow sequence, characteristi of mafic metavolcanics with the Southern Volcanic Belt of cally amygdaloidal and with large pillows (Satterly 1941, the Sioux Lookout area. It is noteworthy however that Pal 1943). Mafic and ultramafic intrusions occur within this onen and Speed (1977) have delineated gabbroic intru upper sequence at the town of Wabigoon. sions in the Southern Volcanic Belt east of Sandybeach For descriptive purposes, the upper and lower se Lake, and that magnetic highs similar to those that overlie quences of the Wabigoon Volcanics are respectively these gabbros occur southwestward into MacFie, South named the Upper Wabigoon Volcanics and the Lower worth, and Avery Townships, and also over the Tobacco Wabigoon Volcanics in this paper. Lake gabbro southeast of Dinorwic Lake. If all of these Further south, in the Manitou-Stormy Lakes portion of gabbros are an integral part of the volcanic stratigraphy the belt, correlation of volcanic units has been made this may indicate the general continuity of volcanic se (Blackburn 1976b) across the Manitou Straits Fault: a quences from the Southern Volcanic Belt southwestward previously unnamed lowermost sequence of pillowed into the areas mapped by Satterly. mafic flows, on the order of 8000 m thick, that occurs A distinct change in supracrustal rocks occurs southeast of the fault can be traced from Lower Manitou SAVANT LAKE—CROW LAKE across a sharp faulted contact formed by the Wabigoon quence where it strikes north on the north side of Kakagi Fault (Satterly 1943; Pettijohn 1939; Blackburn in Trowell Lake. Edwards (in Trowell et al. 1977) has interpreted et al. 1977; Blackburn 1979b) along the north shores of them to be one and the same stratigraphic unit that has Eagle and Wabigoon Lakes, and the southeast shore of been disrupted by the east-trending faults underlying Ka Sandybeach Lake. Metasediments to the north of this kagi Lake. fault are the along-strike equivalents of metasediments at Northeast of the Pipestone-Cameron Fault, complex Minnitaki Lake, suggesting their inclusion within the Min- folding coupled with lack of detailed mapping in the vicin nitaki Group. Unlike the strata to the south of the fault, ity of Caviar Lake to Lobstick Bay in the northwest, and these sedimentary rocks have been tightly folded about Hill Lake in the east, has prevented a complete strati east-trending axes (Blackburn in Trowell et al. 1977; graphic analysis. However, detailed mapping by Davies Blackburn 1979b). (1973), Kaye (1973), and Edwards (1976), and additional investigation by Edwards (/nTrowell etal. 1977) suggests that a lower pillowed mafic flow sequence predominates Kakagi-Atikwa Lakes Sub-Area in most of the area, and is overlain by a mixed sequence of intermediate and mafic flows and pyroclastics, and mi The Kakagi-Atikwa Lakes sub-area is divided by the nor felsic flows and tuffs. This upper sequence is discon- Pipestone-Cameron Fault (Edwards 1976). Correlation of tinuously exposed in synclinal areas at Dogpaw Lake, the lithologies across this fault, although suspected, has not east end of Rowan Lake, east of Hill Lake, and in the vi been possible to date. cinity of Yoke and Straw Lakes. Southwest of the fault, an east- to north-facing as A similar sequence is exposed in the core of an anti semblage is complicated by folding. In the west the lower cline at Otterskin Lake. A thick, predominantly south fac part of the assemblage is a thick previously unnamed ho ing, sequence of mafic flows lies above it, and is here moclinal, east-facing sequence here called the Snake named the Brooks Lake Volcanics. Bay Volcanics, composed predominantly of pillowed Northward, from Caviar Lake toward Populus Lake, mafic flows. South of Kakagi Lake the lower part of the as mapping by Davies and Watowich (1958), Davies (1973), semblage is an equally thick, previously unnamed se and Kaye (1973), and additional investigation by Ed quence, here called the Katimiagamak Volcanics, com wards (/nTrowell etal. 1977) and Blackburn (/nTrowell et posed of predominantly north-facing pillowed mafic flows al. 1978), suggest that tight folding which includes at that have been extensively intruded by gabbroic sills. least three folds, a syncline flanked on either side by anti Correlation is made between these two sequences via a clines, extends northeastward. The name Populus Vol salient of the volcanic belt that lies between Sabaskong canics (Davies and Watowich 1958) is extended here to Bay and Whitefish Bay, Lake of the Woods. all these metavolcanics. Both the Snake Bay and Katimiagamak Volcanics It has recently been suggested (Blackburn /nTrowell are overlain by an upper sequence of intermediate pyroc et al. 1978) that the large gabbroic intrusion at Mulcahy lastics and metasediments that has been extensively in Lake is a layered differentiated body that now faces truded by differentiated ultramafic to mafic sills (Ridler northwestward. There is meagre information from pillow- 1966; Kaye 1974a,b; Davies and Morin 1976). The se top determinations by Davies and Watowich (1958) to quence was previously unnamed: it is here called the Ka suggest that the mafic metavolcanics that it intrudes also kagi Lake Volcanics. A number of east-northeast-trend face northwestward, suggesting that the intrusion is a sill. ing folds occur in this sequence, and have been shown to As in the Wabigoon-Manitou Lakes area, a distinct post-date emplacement of the sills (Cuddy and Clifford change in supracrustal rocks occurs across a sharp con 1972; Schwerdtner et al. 1979. Edwards (in Trowell et al. tact northwest of the Populus Volcanics. Mapping by Bur 1977) has suggested that the central part of Kakagi Lake wash (1934) and Davies and Watowich (1958) indicated is underlain by faults that separate east-trending metavol- predominantly sedimentary rocks, called the Warclub se canics south of the lake from north-trending metavolcan- ries by Burwash (1934). Extensive felsic metavolcanics ics north of the lake. are also present north of Lobstick Bay (Burwash 1934). Sedimentary rocks occur at three separate places in Recent work by Edwards (in Trowell et al. 1977) and this southern portion of the Kakagi-Atikwa Lakes area: at Blackburn (/nTrowell etal. 1978) has shown that the met Esox Lake, west of Sucan Lake, and at Schistose Lake. asediments are tightly folded, and also that further pyroc Their stratigraphic equivalence has been demonstrated lastic rocks are present, particularly at Warclub Lake. The by their position above Katimiagamak Volcanics (Ed name Warclub Sediments is used here for this heteroge wards 1976; Edwards and Sutcliffe 1977). They pass lat neous assemblage of metasediments and metavolcan erally westward into metasediments composed of tuffa ics, with the understanding that it is in all probability strati- ceous debris, to tuff at the base of the pyroclastic graphically equivalent, as suggested by Davies and sequence on the south side of Kakagi Lake. This tuff is Watowich (1958), by direct continuance along strike shown as tuff-wacke on Kaye©s (1974a,b) maps. Similar northeastward, with metasediments north of Eagle and "tuff-wacke" occurs higher in the upper pyroclastic se Wabigoon Lakes, and further east with the Minnitaki Group. units they are mostly towards or at the top of the se General Stratigraphic quences. In the Manitou-Wabigoon Lakes area the Boyer Relationships Lake Volcanics, a thick sequence of mafic flows, structur ally overlies both sedimentary sequences and intermedi In any attempt at correlation of stratigraphic sections de ate to felsic pyroclastics of the Manitou Group, while the termined for each of the geographic areas discussed in Upper Wabigoon Volcanics are predominantly mafic the previous section, the following two reservations must flows overlying mixed mafic to felsic metavolcanics. The be kept in mind. Firstly, the present state of detailed map mafic flows of the Central Sturgeon Lake Volcanics struc ping is such that in many cases individual units have not turally overlie both the North and South Sturgeon Lake yet been traced from one geographic area to the next. Volcanics, and are therefore at the top of the sequence in Secondly, sequences are disrupted, both by tectonism this area. South of Rowan Lake, the Brooks Lake Volcan and by batholithic invasion. Sense and amount of move ics may overlie the mixed sequence at Rowan Lake, and ment on a number of long faults, e.g. Pipestone-Cameron therefore be at the top of this sequence. Fault, Manitou Straits Fault, Wabigoon Fault, Little Vermi 4. Thick sequences of clastic sedimentary rocks are lion Fault, Miniss River Fault, are not well documented. associated laterally and vertically with portions of the vol Emplacement of large granitic bodies, e.g. Atikwa Bathol canic sequences that are highly variable in composition ith, Basket Lake Batholith, Irene-Eltrut Lakes Batholithic and texture. In contrast, few sedimentary rocks are asso Complex, Lewis Lake-Robinson Lake Batholithic Com ciated with thick sequences of mafic flows, whether those plex, has probably removed voluminous amounts of vol at the base of sequences, or those towards the top. At canic rock by stoping, particularly from the base of indi Savant Lake, at Vermilion and Minnitaki Lakes, and in the vidual portions of the sequence. Manitou Lakes, much of this clastic sediment has been However, using certain marker units, and by obser shown to be derived by degradation of volcanic edifices vation of general stratigraphic sequences, a tentative that must have emerged above sea level. In fact, alluvial correlation has been made throughout the study area sedimentary facies have been documented at Vermilion (Table 1). Lake (Turner and Walker 1973) and at Manitou Lakes Five general observations are of paramount impor (Teal and Walker 1977). It is also notable that clastic sedi tance in making this preliminary correlation. Illustration of mentary units occur predominantly in two zones, as previ the five general observations is made in Figure 2. ously noted by Pettijohn (1937, 1972), one near the north 1. Discounting the many reversals due to folding, edge of the Savant Lake-Crow Lake belt, and marginal to doming due to batholithic emplacement, and complica the English River Subprovince, and the other more inter tions due to faulting, it can be noted that sequences pre nal, but nearer the south side of the metavolcanic-met- dominantly face inward, toward the centre of the belt. In asedimentary belt. The former can be traced continu particular, around the periphery of the belt, volcanic ously for a distance of 180 km from the vicinity of Sioux rocks near the contact with enclosing batholiths invari Narrows in the west to Sioux Lookout in the east. Clastic ably face inward. This is the case especially at Kakagi metasediments at Savant Lake may be considered to be Lake (adjacent to the Aulneau and Sabaskong Bathol the eastern extension of these sediments, though sepa iths), from Vickers through to Wapageisi Lake (adjacent rated by faulting along the Miniss River Fault system. The to the Irene-Eltrut Lakes Batholithic Complex), from Bluett latter, internal, zone consists of isolated occurrences at Lake through to Sioux Lookout (adjacent to plutonic rocks Kakagi Lake, Schistose Lake, Pipestone Lake, and Esox of the English River Subprovince), and at Savant Lake, Lake, and the more or less continuous 60 km long Mani where the volcanic belt faces inward from the surround tou Lakes sedimentary unit. Metasediments at Raleigh ing plutonic rocks. Lake, southeast of the study area, and those at Sturgeon 2. Where thick stratigraphic sequences commence Lake are similarly situated internally, but toward the south at base with a thick succession of mafic flows, these are side of the belt. situated at the margins of the Savant Lake Crow Lake 5. Ironstone-bearing formations, predominantly of belt. Near Sioux Lookout the basal Northern Volcanic oxide facies, occur discontinuously within these two clas Belt, composed of submarine mafic flows, is situated at tic sedimentary zones. It is probable that within each the northern margin of the belt, while in the Manitou-Wabi- zone these rock-stratigraphic units are correctable and goon Lakes area, the basal Wapageisi Volcanics are situ therefore represent a time-stratigraphic interval. It is also ated at the southern margin. At Kakagi Lake the basal possible, but quite speculative at this time, that these Snake Bay and Katimiagamak Lake mafic flows are situ chemical sediments were precipitated during the same ated at the southwest closure of the belts, while at Savant time interval in each zone because of their association Lake the basal Jutten Volcanics are situated at the north with thick sequences of clastic sediments and because east closure of the belt. of their apparently similar stratigraphic position. 3. Within and away from the margins of the Savant The authors (Blackburn ei al. 1978) have tentatively Lake-Crow Lake belt, highly variable sequences of mafic suggested on the basis of these observations that the Sa to felsic flows and pyroclastics predominate. Where thick vant Lake Crow Lake belt when considered in isolation sequences of mafic flows occur in these upper volcanic shows a degree of bilateral symmetry. SAVANT LAKE—CROW LAKE
o -jCO .y.tf) l 2 t! o c :oCO O ,
li
CO o 15 5 k. CO c| -o: 0 *
O X O o x< D 2 goe (/^
o 2 O O o O CO 0 03 c y is n 1 1 ^ 81 •^ 3 S LU 01 to S2 ^ —\ OC ID -^ .1 w 'E ^ i^ T3 3 .^ I-W ^^ Sediments 5 u Sg 0 eu 'P 1 s os i ^ si IS go ^ E | e c 5 o
ZQ. u-Jg *- c o g fi ±< Q. > h- LU < LU Uf ^ ^ CO ^ tf rf o CU C HI CO x -i CD 3o E to OT .In TJ 1.8 c?y CLU. 'i1 s CU 'i S "o o CO s S Y •z 4-' i P 0 f 15 CO O 03 c o co o si :*^ to^ ^> (8(3 l L eal co O) -C H^o s lo o l o 2 w CtJ CO .0. -C CO .o .O Q. to O -p -Q -iO) ^TO ^ ^ O d) si CD ^: CQ l .0) SAVANT LAKE—CROW LAKE ics are shown in Figure 5. None of these sequences Preliminary Geochemical shows a well developed trend comparable with Figure 4. Synthesis However, all three sequences contain samples that fall in the basaltic komatiite field, and also close to the komati A first evaluation of major element analyses of more than itic trend as shown on Figure 4. In particular, the Wapa 1000 rock samples taken by the authors supports and geisi Volcanics especially indicate this trend. By far the augments the general stratigraphic relationships outlined majority of samples fall in the tholeiitic field, and in all above. In parts of the study area analytical work was not three cases most are on the high-magnesium side of the complete at time of writing. We have used 152 analyses high-magnesium/high-iron divider. All samples analyzed from a previous study by Goodwin (1970) to augment in are from flows. To date no flows with spinifex texture gen formation in those locations. All other analyses either erally considered to be characteristic of true komatiites have been presented in Ontario Geological Survey publi (Nesbitt and Sun 1976) have been found in any of the cations (Edwards 1976, 1978, in prep, Blackburn 1976a, three sequences. In view of the paucity of samples that 1979a,c, in prep, Trowell 1974a, 1976, 1977, 1978, in fall in the basaltic komatiite field and absence of spinifex prep) or will be included in the final report for the present textures, we prefer to designate these sequences as ongoing project. magnesian tholeiitic flows (MTF). Jensen (1976) has shown that a plot of cation per Mixed sequences of felsic to intermediate pyroclas centages of AI203, FeO -i- Fe203 -i- TiO2 and MgO, normal tics and subordinate flows, and mafic flows and subordi ized to 100 percent (Figure 3) can be used to clearly dis nate pyroclastics are volumetrically the predominant vol criminate between suites that he maintains are canic assemblages in the study area. Plots for each of characteristic of calc-alkalic, tholeiitic, and komatiitic vol nine sections are given in Figure 6. In three of the sec canism (Figure 4). It should be noted that all three suites tions, namely Lower Wabigoon Volcanics, Rowan Lake, shown on Figure 4 overlap in the region of magnesian and Kakagi Lake, supplementary data has been included tholeiitic flows (Figure 3). Therefore if the full development from Goodwin (1970), in order to demonstrate the full of a particular suite is not present, e.g. high-magnesium range of compositions. On all nine plots samples fall in members of the komatiitic suite, or high-iron members of both calc-alkalic and tholeiitic fields, but predominantly in the tholeiitic suite, difficulty may be encountered in dis the calc-alkalic field. Only in the case of the Handy Lake criminating suites. The empirical divider separating high- Volcanics (Figure 6) do any samples fall in the komatiitic iron tholeiitic basalts from high-magnesium tholeiitic ba field of Figure 3. Almost all triangles show considerable salts provides a convenient reference in such cases. scatter of data points. A distinct tendency toward the Plots of samples from the Jutten Volcanics, from the calc-alkalic trend of Figure 4 is demonstrated in all cases Northern Volcanic Belt, and from the Wapageisi Volcan except Rowan Lake where dacitic to rhyolitic calc-alkalic * SOUTH AFRICA •f VITI LEVU, FIJI SKAERGAARD A LIQUIDS A GRANOPHYRE Rock sampli {approximate} AI 2 03 MgO MgO Figure 3 Classification of subalkalic volcanic rocks by Figure 4 Jensen cation plot comparing patterns of vari Jensen cation Plot involving cation percent ation of komatiitic, tholeiitic, and calc-alkalic ages of AI2O3, FeO + Fe2O3 + TiO2, and MgO rock suites (from Jensen 1976). (from Jensen 1976). 10 rocks appear to be virtually absent, and the Lower Wabi chemical signature to the other four sequences. As with goon Volcanics where a distinct iron-enrichment trend is the thick flows at the bases of the sequences (MTF) there in evidence, with many rhyolites, dacites, and andesites is no well developed trend comparable with Figure 4. In falling in the tholeiitic field of Figure 3. Because all nine contrast to MTF sequences, samples that fall in the koma- suites contain samples that plot in the tholeiitic and calc- tiitic field are only found in the Boyer Lake Volcanics (one alkalic fields of Figure 3, we designate them as tholeiitic sample) and the Katimiagamak Volcanics (one sample). to calc-alkalic flows and pyroclastics (TCFP). In similarity to MTF sequences, by far the majority of sam Plots from five sequences of thick upper mafic flows ples fall in the tholeiitic field, but in contrast to MTF se are shown on Figure 7. Of these, four (Central Sturgeon quences in all five cases most are on the high-iron side of Lake Volcanics, Boyer Lake Volcanics, Upper Wabigoon the high-magnesium/high-iron divider. Also in contrast to Volcanics, Brooks Lake Volcanics) are from the top of se MTF sequences there is a distinct tendency toward iron quences in their respective areas, as noted in the previ enrichment. Because no distinct tholeiitic trend, as indi ous section. The fifth sequence, that at Katimiagamak cated on Figure 4, is present we designate these assem Lake, is conversely at the base of the sequence in the Ka blages as Fe-tholeiitic flows (FTF) rather than high iron kagi Lake area. It is stratigraphically equivalent to basal tholeiites as per Jensen©s (1976) classification. sequences at Snake Bay, for which sufficient information Composite plots of all 1191 points (Figure 8) further on chemistry is at present not available. The Katimiaga emphasises the tripartite division of the three suites, and mak Volcanics are included here because of their similar also their overlap in the vicinity of the magnesian tholeiitic field. JUTTEN VOLCANICS NORTHERN VOLCANIC 100 POINTS BELT FeO + P62O3 + TiOo AI2O3 MgO WAPAGEISI VOLCANICS Figure 5 Jensen cation plot for Jutten Volcanics, Northern Volcanic Belt and Wapageisi Volcanics, showing their tholeiit ic, relatively magnesian, character. 11 SAVANT LAKE—CROW LAKE miagamak Lake where they are predominantly Fe-tholeiit- Correlation of Geochemistry ic, are predominantly magnesian (though generally less With Stratigraphy than 10 weight percent MgO). Middle mixed sequences of Figure 2 are highly variable, from tholeiitic to calc-alkal ic, and in general show a distinct calc-alkalic trend. Up per mafic flow sequences are predominantly Fe-tholeiitic. Regional It has been suggested by Goodwin (1968) that Ar The distribution of the three types of volcanic suites de chean "greenstone" belts are characterised by a general progression upwards in sequences from a basal basaltic scribed in the previous section is shown on Figure 9. flow "platform" through an intermediate andesitic to daci- Comparison of Figure 9 with Figure 2 indicates lower mafic flow sequences are tholeiitic and, apart from Kati tic, predominantly pyroclastic, stage, to eruption of rhyol- ites, the latter phases constituting an emergent island 154 POINTS (82 FROM GOODWIN, 1970) LOWER WABIGOON VOLCANICS ROWAN LAKE 47 POINTS (24 FROM GOODWIN, 1970) TiO2 98 POINTS 30 POINTS (18 FROM GOODWIN, 1970) KAKAGI LAKE AI2O3 MgO MANITOU SECTION Figure 6 Jensen cation plots for Rowan Lake Volcanics, Kakagi Lake Volcanics, Lower Wabigoon Volcanics, Manitou Lakes section, North and South Sturgeon Lake Volcanics, Handy Lake Volcanics, and Beckington Road and Morgan Island sections of the Northeast Arm Volcanics showing their calc-alkalic to tholeiitic character. 12 "edifice" stage. In northwestern Ontario, Wilson et al. fore rests on a single section, that at Snake Bay-Kakagi (1974) have suggested that a four-fold subdivision of vol Lake. The present study does not confirm this four-fold canic sequences is in evidence, namely a lower basic, subdivision to prevail throughout the Savant Lake Crow middle basic, middle felsic, and an upper cyclic. This Lake area. Tentatively, a broad three-fold subdivision is analysis was based essentially on two cross-sections, suggested here although the superposition of thick Fe- one from Snake Bay upward through the Kakagi Lake se tholeiitic flows above the tholeiitic to calc-alkalic flows quence, and a second from Wapageisi Lake upward and pyroclastics is at least in part due to faulting; in the through the Stormy Lake succession, to Kawashegamuk Manitou Lakes area, Blackburn (1976b, in prep.) has Lake. Although their Snake Bay-Kakagi Lake section is suggested that the Boyer Lake Volcanics are thrust on entirely valid, that at Wapageisi-Kawashegamuk Lake is top of the Manitou Group metasediments and pyroclas complicated by a major synclinal fold axis not recognized tics, and may be the lateral equivalents of Wapageisi Vol by them (Blackburn 1976b). Their generalization there canics. HANDY LAKE VOLCANICS 69 POINTS NORTH STURGEON LAKE VOLCANICS 72 POINTS 79 POINTS NORTHEAST ARM VOLCANICS (BECKINGTON ROAD SECTION) AI 203 MgO SOUTH STURGEON LAKE NORTHEAST ARM VOLCANICS VOLCANICS (MORGAN ISLAND SECTION) 13 SAVANT LAKE—CROW LAKE Local al. 1977). To illustrate this elsewhere in the study area we have chosen a section through TCFP and overlying FTF The greatest chemical variations in the study area are at Wabigoon Lake (Figure 10). This portion of the north- shown by the above geochemical synthesis to be in the facing homoclinal sequence is divisible on a chemical TCFP sequences. Much of this is due to multiple tholeiitic basis into nine units (numbered 1 to 9 from base to top). to calc-alkalic cycles. Such can be shown to be the case Each of the fields are distinct. The cyclical nature of for example at Sturgeon Lake (Trowell in prep, Franklin et the volcanism is evident, with progressive enrichment in UPPER WABIGOON VOLCANICS BROOKS LAKE 34 POINTS (28 FROM VOLCANICS GOODWIN, 1970) 61 POINTS FeO -i- F02O3 * TiO2 70 POINTS AI2O3 MgO CENTRAL STURGEON LAKE VOLCANICS BOYER LAKE VOLCANICS KATIMIAGAMAK VOLCANICS Figure 7-^ensen cation plots for Brooks Lake Volcanics, Katimiagamak Volcanics, Boyer Lake Volcanics, Upper Wabi goon Volcanics, and Central Sturgeon Lake Volcanics showing their tholeiitic, relatively iron-rich, character. 14 iron with each successive pulse of mafic magma. Within It should be noted that some of these chemically defi TCFP possibly three cycles can be recognized: 1 through ned units correspond to distinct physically defined units. 3; 4 through 5; and 6 through 8. Unit 9 is distinctively Basaltic units 1, 4, 6, 7 and 9 are flows; more felsic units higher iron tholeiite than preceding phases, and may rep 2, 3, 5 and 8 are predominantly pyroclastic. Paralleling resent the base of a fourth, overlying cycle within FTP. iron enrichment, basaltic flows become more distinctly FeO + F62O3 4- TiO2 MgO MTF TCFP FTP 260 POINTS 705 POINTS 226 POINTS Figure 8—Composite Jensen cation plot of 1191 samples from the Savant Lake—Crow Lake area comparing the chemi cal compositions of the three volcanic suites. MAGNESIAN THOLEIITIC FLOWS (MTF) THOLEIITIC TO CALC-ALKALINE FLOWS AND PYROCLASTICS (TCFP) FE-THOLEIITIC FLOWS (FTF) SEDIMENTS N FAULTS ^*"* IRON FORMATION O 50 100 KM CROW (KAKAGDTAKE Figure 9—Sketch map to show distribution of the three volcanic suites in the Savant Lake—Crow Lake area. 15 SAVANT LAKE—CROW LAKE pillowed, the pillows larger in size, and inter-pillow mate granitic batholiths are an integral part of the structural rial more prominent. complexity. Although it remains to be shown in detail to what extent their emplacement has deformed the supra crustal rocks, it has been suggested at a number of places (Blackburn 1979a, in prep, this study; Edwards Approach to a Tectonic Model 1978; Trowell 1974a) that local shallow level intrusive phases of batholiths have erupted at the surface, and In preceding sections it has been shown that geochemi particularly during TCFP volcanism. Conversely, nowhere cal analysis supports and augments the stratigraphic within the study area have volcanic rocks been shown to synthesis of the volcanic-sedimentary units. Subjacent FeO * Fe2 O3 -i- TiO2 \ RHY. \ D AC A AND.\ BAS AI 2 03 MgO Figure 10—Section through tholeiitic to calc-alkalic flows and pyroclastics (TCFP) and overlying Fe-tholeiitic flows (FTP) at Wabigoon Lake. Sample traverse shown as heavy line. Portions of Jensen cation diagrams show fields for units 1 to 9, with the following number of samples per unit: 1-26, 2-7, 3-5, 4-4, 5-5, 6-6, 7-7, 8-9, 9-6. 16 N —— ENGLISH—— WABIGOON SUBPROVINCE RIVER SUBPROVINCE KAKAGI-SAVANT LAKES GREENSTONE BELT Figure 11—Cross-section illustrating hypothetical stage of development during time of late tholeiitic to calc-alkalic flow and pyroclastic (TCFP) volcanism. MTF indicates magnesian tholeiitic flows; crosses indicate two phases of granitic intrusions. lie on a granitic basement. However, there is considera ture (e.g. Anhaeuser 1975; Glikson 1978; Gorman et al. ble evidence that batholithic emplacement commenced 1978; Young 1978; Burke et al. 1976; Baragar and early in the evolutionary history as shown by the granite- McGlynn 1976, 1978; Goodwin and West 1975; Talbot clast conglomerates that unconformably overlie MTF, 1973) leads us to suggest that absence of a recognizable lowermost, Jutten Volcanics at Savant Lake. Similarly, granitic or gneissic basement upon which the lowermost granitic clasts are present in uppermost conglomerates mafic volcanic rocks can be shown to have been laid in the Manitou Group. down is not inconsistent with a mobilist or plate tectonic Significantly, the presence of MTF, in all cases at the model. Such a model would account for crustal down base of sequences, discontinuously along the northern warping, such that MTF sequences on either side of the and southern edges of the belt, combined with its great belt might represent elements of opposing oceanic thickness, in places on the order of 10 000 m, suggests plates. Langford and Morin (1976) have speculated on a its earlier continuity, possibly beneath the belt. Thin pillow plate tectonic model for this part of Superior Province rims, general absence of amygdules and hyaloclastite, based primarily on lithochemical data. leads us to interpret them as deep-submarine, probably Voluminous sediments derived by degradation of fissure outpourings. Also characteristic are plagioclase- volcanic piles and emerging batholiths were deposited phyric mafic flows, some of which, for example in the within both what is now the Wabigoon Subprovince and Manitou-Stormy Lakes area, can be traced for tens of ki northwards within what is now the margin of the English lometres along strike. Over a protracted period, bathol River Subprovince. ithic invasion concomitant with crustal downwarping The presence of mafic tholeiitic volcanism structur would have removed much of this sequence by stoping ally at the top of some of the sequences is not as yet un while at surface calc-alkalic volcanism produced island derstood. Its present distribution within the belt, either in edifices (Figure 11). the cores of synclines, or terminated against faults, sug Reference to tectonic models presented in the litera gests it may have formerly been more continuous. In the 17 SAVANT LAKE—CROW LAKE Manitou Lakes portion of the area Blackburn (1976b) has shear folding associated with movement along the Stur suggested that Boyer Lake Volcanics, of FTP affinity, geon Narrows Structural Zone may have masked initial have been technically emplaced, along a thrust decolle association between these gold occurrences and vol ment, above metasediments and pyroclastics of the Man canic stratigraphy. itou Group. Such an interpretation is not inconsistent with Production at the St. Anthony mine was from a de plate tectonic theory, which emphasises dominance of posit within granitic rocks that intrude the Northeast Arm horizontal shortening over vertical tectonics (Burke era/. Volcanics (Trowell 1977, in prep). 1976). Gold mineralization at the Darkwater mine is found in Many of the FTP sequences, unlike MTF sequences, quartz veins in the Beidelman Bay Pluton, which appears are amygdaloidal, suggesting a shallow submarine envi to be a subvolcanic felsic intrusion (Trowell in prep). ronment, and they are rarely plagioclase-phyric. These characteristics, in conjunction with their different chemis Sioux Lookout Sub-Area try, suggest that they are not lateral equivalents of lower most MTF sequences, but may have originated in a differ In the Sioux Lookout area the preponderence of gold oc ent geochemical environment. McMaster (1978) has currences are in the Central Volcanic Belt. Many are suggested from trace element data that lowermost (MTF) associated with hypabyssal, probably subvolcanic intru Wapageisi Volcanics in the Manitou-Stormy Lakes portion sions while several, for example the Newlund or Goldlund of the area are of ocean-floor affinity.whereas Boyer Lake deposit (Webb 1948; Speed 1978; Page 1979), appear to Volcanics (FTP) are of island-arc or back-arc-basin affi be associated with granitoid intrusions that may be either nity. These conclusions are also not inconsistent with superimposed on volcanic stratigraphy or of subvolcanic plate-tectonic theory. origin. It is of interest that a northeast-trending zone of ©spherulitic lavas© (Webb 1948; Armstrong 1951) occurs at the same approximate stratigraphic level as, and in close proximity to, the Goldlund deposit (Webb 1948; Armstrong 1951) and past explored ground to the east (Armstrong 1951; Chisholm 1951). Examination of these Mineral Deposits1 ©spherulitic lavas© (Trowell 1977; Reid 1978) indicates that some of them are variolitic lavas containing felsic varioles possibly of immiscible origin (Gelinas et al. 1976). Data Gold are not available but felsic varioles may be preferentially enriched in gold with respect to the matrix or the average Three broad categories of gold occurrences can be rec abundances of gold in igneous rocks. ognized in the area: 1) those tied to volcanic and subvol Three gold occurrences in the northeast extension of canic stratigraphy, very often the same stratigraphy as the Central Volcanic" Bejt occur at the same stratigraphic suggested for base metal deposits and (subvolcanic) level in mafic metavolcanics (Page 1978b). Gold here oc porphyry copper and molybdenum deposits, respec curs in quartz veins accompanied by carbonate and sul tively; 2) those occurrences associated with later felsic in phides (pyrite-l-galena sphalerite chalcopyrite) (Page trusions that possibly intrude volcanic stratigraphy; and 1978b). These occurrences may be time-equivalent and 3) those occurrences situated within quartz veins having possibly related to emplacement of the intrusion, proba no apparent relationship to volcanic activity or igneous in bly subvolcanic, at Clamshell Lake (Page 1978b). trusions. Individual occurrences often combine features A gold-silver occurrence on Vermilion Lake (Eimiller of more than one class. Claims, Johnston 1972) is situated along the probably secondarily silicified contact between quartz porphyry of Savant Lake Sub-Area subvolcanic origin to the south and tuff and conglomerate to the north. It is possible that this contact was actually an Gold in the Savant Lake area (Bond 1977, 1978, 1979) erosional unconformity and that residual placer gold was occurs in quartz veins situated throughout the Jutten and subsequently concentrated during silicification of this Handy Lake Volcanics. zone. Sturgeon Lake Sub-Area Wabigoon-Manttou Lakes Sub-Area Gold along the Northeast Arm of Sturgeon Lake similarly Gold deposits mostly in quartz veins occur in the Eagle- occurs in quartz veins. Here, however, shearing and Wabigoon Lakes area along a specific horizon, distinctly related to felsic volcanism, and associated subvolcanic plutonism. At Eagle Lake numerous occurrences and prospects (Moorhouse 1941) are located either within or 1 Locations of specific deposits discussed in this section can be found in Compilation Maps 2115 (Davies and Pryslak 1967), peripheral to a lobe of the Atikwa Batholith. One of these, 2169 (Davies et al. 1970), and 2175 (Ferguson et al. 1970), the the Baden Powell mine, is located well within the granitic Ontario Mineral Map 2310 (ODM 1974), and in reports by Go phase of the batholith. Other gold occurrences northeast odwin (1965), Beard and Garratt (1976), and Breaks et al. of Meridian Bay are within felsic flows and tuffs. Field in (1978). Maps 2115,2169 and 2175 are currently being revised. vestigation during the course of this study has shown that 18 there is a transition from granitic rocks through to felsic Kakagi-Atlkwa Lakes Sub-Area flows in this location and that this lobe of the batholith is a subvolcanic phase. At Straw Lake, in the vicinity of Pipestone Lake, gold was Further east, on the west side of Wabigoon Lake, nu produced from the Straw Lake Beach mine, located in fel merous gold occurrences and prospects (Satterly 1943) sic metavolcanics (Edwards in prep, Edwards in Trowell occur at the same stratigraphic level as those at Eagle et al. 1977). Near Sioux Narrows, gold was produced Lake. Two past producers, the Bonanza mine and the Re from the Regina mine, located in quartz veins associated deemer mine are located here. Other gold occurrences with altered mafic rocks adjacent to a small granitic stock are at Contact Bay of Wabigoon Lake, where the Dor6 (Fraser 1945; Burwash 1934; Edwards in Trowell et al. Lake lobe of the Atikwa Batholith may be a subvolcanic 1977). It is possible that the stock was either the source source of felsic volcanism. for or concentrated the gold. In the Manitou Lakes, numerous gold occurrences Other abundant occurrences and prospects in the and prospects (Thomson 1934, 1942; Blackburn 1976a, Kakagi-Rowan Lakes area are in quartz veins scattered 1979a,c) are located principally in quartz veins associ throughout the mafic to felsic volcanic sequences, with ated spatially with calc-alkalic pyroclastic volcanism little apparent stratigraphic control. Gold also occurs with- northwest of the Manitou Straits Fault. Three past produc copper mineralization at the Maybrun mine and the Em ers, the Laurentian, Elora, and Big Master mines are all lo pire mine, both in mafic metavolcanics, in the vicinity of cated at Trafalgar Bay of Upper Manitou Lake, at the tran Atikwa Lake (Davies 1973). sition from underlying calc-alkalic pyroclastic volcanism to overlying mixed tholeiitic to calc-alkalic flows and py roclastics. Earlier interpretations (Thomson 1934, 1936, Base Metals 1942) related the mineralization to intrusion of felsic dikes, and to association of a structural "break". More re Base metal mineralization occurs primarily in three gen cently Blackburn (1979a) has suggested that the felsic eral environments in the area: 1) directly associated with units are flows and therefore that the gold is genetically volcanism; 2) associated with subvolcanic and granitoid associated with the volcanism. plutons; and 3) associated with mafic and ultramafic in A number of occurrences and prospects north of Ka- trusions and flows. washegamuck Lake are spatially associated with recently identified felsic volcanism and a zone of intense carbona tization (Blackburn in Trowell et al. 1977; Blackburn Volcanogenic Base Metal Sulphides 1979d). The only past producer, the Sakoose (Golden Sturgeon Lake Sub-Area Whale or Van Houten) mine reportedly developed on a quartz-feldspar porphyry intrusion in mafic metavolcan- Mattabi Mines Limited and Sturgeon Lake Mines Limited ics (Thomson 1934), occurs stratigraphically immediately are the only active producers of Zn, Cu, Ag, and Pb in the below a thick sequence of proximal felsic pyroclastic Crow Lake Savant Lake area. Two further deposits breccia and associated tuff, suggesting a volcanic asso await development (Table 2). ciation. TABLE 2 SUMMARY OF BASE METAL SULPHIDE DEPOSITS IN THE STURGEON LAKE AREA. DATA FROM FRANKLIN ET AL. (1977). NAME COMPANY DISCOVERY DEPOSIT TYPE CURRENT ZN CU PB AG AU DATE TONNAGE "/o "/o "/o OZ/T OZ/T ESTIMATE (TONS) Mattabi mine Mattabi Mines Sept. 1969 Zn-Cu-Ag-Pb 136658002 7.5 0.8 0.77 3.10 Ltd. 1 Boundary mine Sturgeon Lakes Oct. 1970 Zn-Cu-Ag-Pb-(Au) 21105842 10.64 2.93 1.47 6.14 0.021 Mines Ltd. 1 Lyon Lake and Mattagami Lake Oct. 1971 8. Feb. Zn-Cu-Ag-Pb 4 029 5002 6.66 1.15 0.63 3.3 Creek deposits Mines Ltd. 1972 1 Producer. 2 All tonnage figures are pre-production estimates. 19 SAVANT LAKE—CROW LAKE All four deposits are in the South Sturgeon Lake Vol As indicated by the coarse amygdules in the overly canics. They occur near the top of the Darkwater and ing flows, and the carbonaceous shales, deposition of the Lyon Lake Volcanic Cycles (Trowell 1977, in prep). metallic elements appears to have occurred in relatively The deposits are conformably situated within inter shallow water on the sea-floor, probably in a restricted mediate to felsic volcanic breccias. The breccias are quiescent environment, and possibly under biogenic dominantly redeposited debris flow deposits, though in controls. the immediate mine areas monolithic felsic breccias could have formed in-situ by autobrecciation of felsic do Savant Lake Sub-Area mes. The breccias are overlain by mafic metavolcanic flows, locally pillowed and coarsely amygdaloidal. Car Similarities between the South Sturgeon Lake Volcanics bonaceous shales occur at approximately the same stra and the Handy Lake Volcanics of the Savant Lake area tigraphic level as the sulphides and in some cases could make the latter a favourable prospecting target for vol be the lateral equivalents of the deposits. The immediate canogenic base metal sulphide mineralization. footwall rocks of these deposits are variably altered North of the town of Savant Lake two base metal oc (Franklin et al. 1975; Hinzer 1977; Trowell in prep). As currences are situated within redeposited volcanic py well, a widespread pervasive alteration of the breccias roclastics and volcanogenic metasediments of the Handy below the ore-bearing horizons has occurred (Lavin Lake Volcanics (Table 3). The occurrences have been in 1976). East of O©Briens Landing an epizonal subvolcanic terpreted to be distal facies with a possible source to the intrusion, the Beidelman Bay Pluton, is situated within the west (Trowell 1978). The Hadley occurre/ice is a small base of the breccia pile and has many of the characteris pod of base metal sulphides, possibly a portion from a tics of porphyry copper systems (Trowell 1974a; Priske larger base metal sulphide body, that was detached from 1974; Franklin et al. 1977). the main body and deposited in its present position. According to Hodgson and Lydon (1977), the main Both the Darkwater Lake and Claw Lake fragmentals requirements for a hydrothermal system are an aquifer of the South Sturgeon Lake Volcanics (Trowell in prep) zone, a heat source, a caprock unit, and recharge and and this section of the Handy Lake Volcanics plot domi discharge channels. The breccia pile not only satisfies nantly in the calc-alkalic field on a cation plot (Jensen the requirement of an aquifer but also could be the 1976). Kyanite and andalusite that occur in the altered source of the metallic elements. The Beidelman Bay Plu footwall rocks at the Mattabi mine are also found within ton acted as a heat source and, as well, probably pro the Handy Lake Volcanics northwest of Evans Lake. This vided various volatiles that aided in the leaching of and development of peraluminous units may be the result of the transporting of the metallic elements as complex ions leaching of the other major elements by an active hy during a period of resurgent or second-boiling activity. drothermal system, the development of specific alumino The anomalous chemistry of the Darkwater Lake Cycle silicate minerals being the result of superimposed meta (Trowell in prep) could indicate that a self-sealing cap morphism. formed as a result of boiling of the discharge fluids as On and to the west of Highway 599, north of the town they rose through the breccia pile. Some of the interca of Savant Lake, coarse breccias of redeposited and py lated mafic metavolcanic flows could have acted as rela roclastic origin are locally intensely carbonatized (Bond tively impermeable barriers confining the fluids circulat 1978); a similar carbonate alteration zone is developed in ing through the breccias. The monolithic autoclastic proximity to the Mattabi mine (Franklin era/. 1977). breccias could represent the explosive eruption products Possible epizonal subvolcanic phases now intruded that would result from boiling of the discharge fluids. Dis by late granitoid phases of the Lewis Lake Batholith charge channels are likely indicated by the alteration (Breaks and Bond 1979) occur marginal to the fragmen- zones present beneath the deposits themselves. TABLE a BASE METAL SULPHIDE OCCURRENCES IN THE SAVANT LAKE AREA (HANDY LAKE VOLCANICS). OCCURRENCE METALS HOST ROCKS MINERALIZATION ASSAY DATA Savant Cu-Zu-Pb-Ag Handy Lake Volcanics Disseminated pyrite, chal 1.670/0 Cu, 1.4407o Zn, Q.28% Pb, 3.46 oz. Occurrence metasediments and copyrite, sphalerite, galena, Ag/ton over width of 3 m (Shklanka, 1969) intermediate tuffs minor pyrrhotite Hadley Zn-Pb-Ag- Handy Lake Volcanics Bands and patches of mas 21.807o Zn, 8.850Xo Pb, U.08% Cd, 1.88 oz. Occurrence (Cd)-(Au) intermediate tuffs sive sphalerite and galena Ag/ton, 0.01 oz. Au/ton over 1.2 m (File and minor chalcopyrite 63.2892, Cam Mines Ltd., Assessment Files Research Office, Ontario Geological Survey, Toronto) 20 tals near the town of Savant Lake. Like the interpreted both surface sampling and a number of drill holes. Disse role played by the Beidelman Bay subvolcanic pluton minated sulphides with associated gold mineralization within the South Sturgeon Lake Volcanics, this now dis are present over a considerable area in rhyolitic flows rupted subvolcanic body could have played the role of and tuffs. In a report for Kamlo Gold Mines Limited (As heat source in the development of a hydrothermal system sessment Files Research Office, Ontario Geological Sur within the Handy Lake Volcanics. vey, Toronto) the values of copper in the best two grab The search for base metal sulphide mineralization in samples taken were reported to be 0.44 percent and 0.72 the Handy Lake Volcanics may be complicated by the percent. A copper assay of 0.76 percent was also re high metamorphic grade and accompanying metasoma ported over a 5-foot length in one drill hole in a sample tism (Bond 1978; Trowell 1978; Lefebvre etal. 1978) and taken from a 50-foot section that assayed an average of by the complex folding. Both the Savant and Hadley oc 0.432 percent Cu. Other drill holes on the property inter currences contain anomalously high mercury values (up sected chalcopyrite in small amounts. Considerable min to 1580 ppb), and the Savant occurrence contains high eral exploration (Assessment Files Research Office, On tin values (up to 650 ppm) indicating that lithogeochemi tario Geological Survey, Toronto) southward from Fornieri cal prospecting methods might aid in delimiting possible Bay to Meridian Bay has shown the presence of iron sul areas of major base metal mineralization. phide and oxide minerals generally in mafic flows, while at Buchan Bay, to the east, exploration has outlined mag Sioux Lookout Sub-Area netite-rich zones that may be along-strike equivalents. To date, no economic mineralization has been discovered In the Sioux Lookout area intermediate and felsic volcanic but this zone is suggested for further exploration. breccias with possible hypabyssal equivalents occur on Moorhouse (1941) outlined a sequence of mixed fel Vermilion Lake (Trowell 1978). The hypabyssal phases sic and intermediate flows and pyroclastics that extend are locally extensively intruded by quartz-tourmaline from Fornieri Bay in the west across Eagle Lake to Spring veins. As well they are quite sericitic and locally pyritic, Bay in the east. Later mapping by Satterly (1943) deli possibly reflecting original hydrothermal alteration. The neated similar lithologies along strike to the east, extend breccias themselves are coarse, possibly near-vent de ing across Wabigoon Lake to Daunais Bay. Considerable posits, and are locally set in an iron carbonate matrix of prospecting and exploration has been carried out along chemical sediment origin (Trowell 1978). Examination of this zone, in the past predominantly for gold. Because of these breccias, and their western extension into the its felsic pyroclastic nature, it is suggested here that it is Bluett Lake area (Breaks and Bond 1975; Page 1979) is also potentially favourable for volcanogenic base metal warranted. (Cu-Pb-Zn) deposits. In addition, the presence of rhyolitic Felsic and intermediate fragmentals, flows, and pos rocks somewhat lower in the section, near Contact Bay of sible hypabyssal equivalents occur east of Sioux Lookout Wabigoon Lake, suggests proximity of a felsic centre of in the area of Superior Junction (Johnston 1972; Trowell volcanism. 1977) and extend to the northeast (Page 1978b). A cop Further to the southeast, between Melgund Town per occurrence is known at Allan Lake, south of Superior ship and Kawashegamuk Lake, investigation by the pres Junction (Johnston 1972), and the Rosnel occurrence, ent workers (Blackburn in Trowell et al. 1977) has iden hosted by carbonatized quartz-sericite schist, comprises tified felsic pyroclastic and flow rocks in the vicinity of disseminated pyrite, chalcopyrite, and sphalerite (Page Church Lake that were not outlined in earlier mapping 1978b). and compilation (e.g. Davies and Pryslak 1967). Explora Other areas near Sioux Lookout that perhaps warrant tion in recent years in this area (Assessment Files Re further exploration are a newly defined zone of intermedi search Office, Ontario Geological Survey, Toronto) has ate fragmentals situated at Southeast Bay, Minnitaki Lake been extensive (Beard 1975; Beard and Rivett 1977, (Bartlett in Trowell et al. 1978), and intermediate to felsic 1978; Beard and Scott 1976), and minor amounts of Cu- breccias in the Pickerel Arm area of Minnitaki Lake (John Zn mineralization have been found (Blackburn 1979d). ston 1969; Palonen and Speed 1977; Trowell in Trowell et In the Manitou Lakes portion of the area Blackburn al. 1978). (1976a, 1977a, 1979a, in prep, /nTrowell et al. 1977) has suggested a number of situations suitable for base metal Wabigoon-Manitou Lakes Sub-Area exploration. These include proximal felsic to intermediate pyroclastics and flows and clastic sedimentary rocks, At Eagle and Wabigoon Lakes felsic to intermediate frag spatially associated with felsic porphyries that intrude the mentals and flows occur toward the top of the lower calc-alkalic sequences (Blackburn 1977b), in particular mixed felsic to mafic sequences. This zone was early re at Frenchman Island of Upper Manitou Lake, at Sunshine cognised as favourable for gold occurrences, but its po Lake, and at Thundercloud and Washeibemaga Lakes. tential for Cu-Zn-Pb mineralization associated with proxi mal volcanic activity is also important. However, in spite Kakagi-Atikwa Lakes Sub-Area of exploration, little mineralization of this kind has been reported to date. Felsic porphyries that intrude and are subvolcanic equiv At the north end of Meridian Bay of Eagle Lake, in the alents of calc-alkalic volcanic rocks are also present at vicinity of Fornieri Bay, chalcopyrite has been reported in Esox Lake and at Dash Lake in the vicinity of Pipestone 21 SAVANT LAKE—CROW LAKE Lake. Because these bodies define centres of felsic vol Page and Clifford 1977, Page 1978a). Copper and cop canism, they represent good exploration targets for vol per-molybdenum occurrences are found within the diori- canogenic base metal sulphides, as discussed by Ed tic phases. A similar pluton situated at David Lake to the wards (1976, 1978, in prep) and by Beard and Scott north contains no reported mineralization. (1976). A porphyritic felsite intrusion on the south shore of At Kakagi Lake Cu-Zn-Ag mineralization has been Vermilion Lake contains a copper occurrence set in an discovered in dacitic tuff south of the Stephen Lake plu enclave of volcanic-clast conglomerate. ton (Davies and Morin 1976). These tuffs can be traced a Copper mineralization is reported in a mafic metavol- considerable distance along strike around fold structures canic enclave in a porphyritic body situated at the east north of Kakagi Lake, and are possibly continuous with entrance to Pickerel Arm, Minnitaki Lake (see Colvine and units called tuff-wacke (Kaye 1974a,b; Edwards 1976) Sutherland 1979, for detailed discussion of this area). and waterlain tuff (Edwards 1976) along the south side of Along the margin of the Lateral Lake Stock several Kakagi Lake. The correlation increases the potential tar molybdenite occurrences occur in late quartz and peg get area for base metal sulphides. matite veins. The descriptions of these occurrences have Northeast of the Pipestone-Cameron Fault, the upper been summarized by Colvine and McCarter (1977) and mixed mafic-felsic sequences in synclinal structures at Page (1979). Yoke, Hill, Rowan and Dogpaw Lakes have been sug gested by Edwards (in Trowell et al. 1977) to be poten Kakagi-Atikwa Lakes and Wablgoon-Manitou Lakes Sub- tially favourable for volcanogenic base metal sulphide Areas mineralization. Molybdenite occurrences have been located at a few scattered occurrences at the edge of the Dor6 Lake lobe Copper and Molybdenum Deposits Associated of the Atikwa Batholith. One of these is near Contact Bay with Subvolcanic and Granitoid Plutons of Wabigoon Lake (Assessment Files Research Office, Ontario Geological Survey, Toronto) and two others are in Several of the porphyritic epizonal subvolcanic plutons the Manitou Lakes area (Blackburn 1976a, 1979c). The that occur throughout the area contain disseminated cop occurrences are in pegmatite veins both within the grani per and molybdenum (and gold) mineralization. As well, tic rocks of the batholith and within adjacent metavolcan- later granitoid plutons contain disseminated molybde ics. Minor occurrence of molybdenite is reported in drill num mineralization. core (Assessment Files Research Office, Ontario Geolog ical Survey, Toronto) from near Mennin Lake, adjacent to Savant Lake Sub-Area the Revell Batholith. Molybdenite has also been found associated with At Savant Lake porphyritic hypabyssal trondhjemite gold in quartz veins and quartz-feldspar porphyry dikes phases marginal to the Handy Lake Volcanics (Bond that intrude mafic metavolcanics at Wapus Lake north of 1978) could represent the remains of an epizonal intru Kakagi Lake (Davies and Morin 1976). The porphyry sion^) now extensively intruded by granitoid phases of dikes appear to be part of an irregularly shaped felsic the Lewis Lake Batholith (Breaks in prep). Minor amounts porphyry intrusion centred on Wapus Lake. of chalcopyrite were observed in these rocks (Trowell Molybdenite associated with copper has been re 1977) where they have been newly exposed by the re ported from gold-bearing quartz veins adjacent to the cently constructed Marchington Road. Stephen Lake pluton, north bf Kakagi Lake (Davies and Morin 1976). However, this has not been subsequently Sturgeon Lake Sub-Area substantiated. Copper and molybdenum mineralization occur in the Bei- delman Bay Pluton at Sturgeon Lake. A possible coeval and comagmatic intrusion, the Shanty Lake Pluton (Tro Copper and Nickel in Mafic and Ultramafic well 1970; in prep) contains disseminated molybdenite Intrusions and Flows with minor chalcopyrite. The Beidelman Bay Pluton has several features characteristic of ©porphyry copper© sys Savant Lake Sub-Area tems (Trowell 1974a; Priske 1974; Franklin era/. 1977), and gold mineralization (see "Gold") at the Darkwater At Savant Lake, metamorphosed ultramafic intrusions, mine (Horwood 1938b, Trowell 1974a) could also be of ranging from peridotite to pyroxenite in composition, are porphyry affinity. situated within the lower Jutten Volcanics at Armit Lake (Hudec 1965; Sutcliffe in Trowell et al. 1977). An ultra Sioux Lookout Sub-Area mafic flow overlies granitoid-clast conglomerate in the At Sioux Lookout a composite trondhjemite-quartz dior- upper eastern portion of Savant Lake. Two anthophyllite ite-diorite stock situated in the Northeast Bay of Minnitaki flows of apparent ultramafic affinity are situated within a Lake may be comagmatic to, and a subvolcanic intrusion basaltic flow sequence of the central Handy Lake Volcan associated with, the Central Volcanic Belt (Johnston ics (Trowell 1978). To date no economic mineralization 1972; 22 has been reported from these areas, but they warrant ex Chibougamau, Quebec, copper-gold mineralization (Al- ploration. Iard1976). The majority of mafic-ultramafic intrusive bodies dis Sturgeon Lake Sub-Area cussed above are located at the edge of the Atikwa Ba tholith. Many of the more dioritic phases can be consid At Sturgeon Lake ultramafic intrusions with mafic high- ered to be derived by hybridization of mafic volcanic magnesian tholeiitic gabbro differentiates occur north of country rock by the emplacement of the batholith, Post Lake and on Mountain Island (Trowell 1974d, 1976; whereas the huge volume of the mafic-ultramafic bodies Zalnieriunas 1978). Nickel sulphide was reported in a dia suggests them to be primary igneous phases. Whatever mond-drill hole from one of the bodies located north of their origin, their spatial distribution at the margin of this Post Lake (Assessment Files Research Office, Ontario batholith is a good exploration guide. Geological Survey, Toronto). A band of pyroxenite cumu To date little mineralization has been found associ late that forms a partial ring around the Bell Lake Alkaline ated either with differentiated ultramafic to mafic sills at Complex contains no known mineralization but may war Kakagi Lake, discussed by Davies and Morin (1976) and rant investigation (Hoad 1970; Trowell in prep). Kaye (1974a,b), or mafic sills intruded into Katimiagamak Differentiated multi-phase mafic intrusions, locally Volcanics (Kaye 1974a,b). However, Edwards (1978) has with minor cumulate ultramafics, are situated within low drawn attention to copper occurrences in mafic-ultra ermost mafic metavolcanic sequences west of Sturgeon mafic sills near Pipestone Lake. Lake (Trowell 1975, in prep). These bodies locally contain Blackburn (1979a) has suggested that anomalously abundant titaniferous magnetite. high nickel values in lake sediments found by Coker and Nichol (1975) in the Manitou Lakes area indicate that the Sioux Lookout Sub-Area basal part of the thick Wapageisi Volcanics mafic flow se quence is a favourable target for sulphide mineralization. In the Sioux Lookout area, mafic and ultramafic intrusions situated within the Southern Volcanic Belt may be good exploration targets (Bartlett /nTrowell etal. 1978). Uranium and Other Lithophile Elements Wabigoon-Manttou Lakes and Kakagi-Atikwa Lakes Sub- Areas In a recent discussion of the geology of the English River Subprovince, Breaks etal. (1978) have given a compre The association of copper-nickel deposits with mafic and hensive discussion of both uranium mineralization and li ultramafic intrusive rocks has been well established by thium-caesium-beryllium-tantalum-tin-bearing pegma previous exploration and mapping near Rowan and tites, that mostly pertains to the area north and west of Atikwa Lakes in the southwest (Davies 1973; Kaye 1973; that under discussion here. Assessment Files Research Office, Ontario Geological In their discussion of uranium, Breaks et al. (1978) Survey, Toronto), and near Nabish Lake, east of Eagle emphasize its occurrence in two distinct lithologic situa Lake and at Contact Bay of Wabigoon Lake (Assessment tions: metasedimentary migmatite, and potassic granitoid Files Research Office, Ontario Geological Survey, Toron association. In addition to their comments it is to be borne to). in mind that extensive metasedimentary migmatite lies Lesser amounts of copper and copper-nickel miner along the northern edge of the Savant Lake Crow Lake alization have also been established in the large gab- belt, between Bluett Lake in the east and at least as far as broic-anorthositic intrusion.at Mulcahy Lake (Moorhouse Dryberry Lake in the west. The project by Breaks et al. 1941, Davies and Watowich 1958) west of Eagle Lake, (1978) terminated southward at 49045©N, so that the ura and in a number of small bodies either marginal to the nium mineralization potential southwest of Eagle Lake Atikwa Batholith (e.g. southwest of Wabigoon Lake), or in was not studied by them. The same lithologies that host ternally emplaced within the volcanic belts (e.g. Boyer uranium in Temple Township, south of the town of Vermi Lake in the Manitou-Stormy Lakes area) (Blackburn lion Bay, appear to continue marginal to the Dryberry Ba 1979a). tholith, possibly continuously around this south-protrud Interest in base metal association of this kind was ing lobe of the English River Subprovince within the generated in the 1950s with the discovery of copper and Wabigoon Subprovince. copper-nickel deposits near Atikwa and Populus Lakes. Breaks etal. (1978) in discussing lithophile elements This subsequently led to the development of the Ken- in highly fractionated residual diatexitic pegmatite phas bridge mine near Populus Lake, and the Maybrun mine at es, mention that ". . . in the Dryden area of Wabigoon Atikwa Lake (the latter being a copper-gold association Subprovince several occurrences containing lithium, and reportedly in mafic metavolcanics) (Davies 1973). beryllium, and a single pollucite-spodumene showing lie Blackburn (/nTrowell etal. 1978) has recently recog near the eastern end of a relatively extensive tourmaline- nized that the Mulcahy Lake gabbroic intrusive body is bearing homogeneous to inhomogeneous muscovite dia layered and bears some resemblance to other layered in texite pluton situated between Vermilion Bay and Ghost trusions that host important ore deposits. It therefore must Lake." These are in Zealand and Brownridge Townships, be considered as a potential host for copper-nickel min and in Webb Township immediately south of the Lateral eralization, or, by analogy with the Dor6 Lake Complex at Lake stock. 23 SAVANT LAKE—CROW LAKE Limited deposit near Sioux Lookout (Johnston 1972) Discussion of Mineralization, where trace chalcopyrite and sphalerite accompany the and Exploration Guide-lines dominant pyrite-pyrrhotite assemblage in a host of carbo- natized mafic hyaloclastite. We have attempted to illustrate how mineral deposits in Sawkins (1976) has emphasized that in addition to the area are associated with specific lithologies and are occurring within mafic volcanic sequences, structural situated at specific stratigraphic levels within the vol complexity and proximity of thick sequences of wacke cano-sedimentary belt. By comparison of mineralization are characteristic of Besshi-type deposits. The occur type, associated host rocks, and stratigraphic setting rence of scattered Cu-Au deposits at the contact be with similar parameters of known mineralization in other tween mafic metavolcanics of the Central Volcanic Belt volcano-sedimentary belts we can outline the location of and sandstone of the Minnitaki Group northwest of San- other favourable lithologies and stratigraphic settings dybeach Lake is suggestive of this type of environment. within the present area. All of the above-mentioned deposits occur along the north side of the Savant Lake -Crow Lake Belt, and in fairly close proximity to the more northerly of the two clas tic zones discussed under "General Stratigraphic Rela Volcanogenic Base Metal Deposits tionships". In Japan, Kuroko type (Sato 1977) base metal sulphide deposits, similar in many respects to those at Sturgeon Lake, are likewise associated with felsic pyroclastics and redeposited fragmentals. They occur at a discrete strati Gold Deposits graphic level, formed over a duration of perhaps 0.3 to 1 million years and extend for 500 km along the volcano- In considering gold deposits in the area it is important to sedimentary belt within the island-arc environment (Ueno note that gold mineralization in the Timmins or Porcupine 1975). While direct application of the mechanism of plate Camp of the Abitibi Belt appears to be intimately associ tectonics has not been substantiated for Archean time, ated with ultramafic (komatiitic) rocks, felsic porphyry physical-chemical parameters as applied to magma gen and carbonate horizons (Pyke 1975; Karvinen 1978). eration of comparable chemistry, and mode of deposition Sea-floor alteration/metamorphism of the ultramafic flows are a basis for comparison. In this respect we can pro and specifically fragmentals has been postulated for ini pose that comparable lithologies to those at Sturgeon tially concentrating gold, allied with subsequent intrusion Lake, as for example, the Northeast Arm Volcanics, the of porphyries. Structure may be important in providing lower Handy Lake Volcanics and the lower volcanic se channelways resulting in gold being deposited in specific quences at Eagle and Wabigoon Lakes are possible tar structural sites as economic-grade deposits. gets for base metal exploration. Samples collected from In a previous discussion, Mackasey et al. (1974) these and other areas of similar lithology are presently noted the close spatial relationship of many gold deposits being radiometrically dated through a geochronological to mafic metavolcanics, and invoked felsic intrusions as program run in conjunction with this project (Davis et al., concentrating agents. In contrast to Timmins, ultramafic in prep.). These ages are intended to complement litho flows are infrequently found in the present area. This fact logic correlations and aid in more precisely identifying could, to some extent, explain the paucity of economic discrete stratigraphic levels favourable for massive sul deposits in contrast to numerous sub-economic occur phide mineralization. rences. The St. Anthony mine is somewhat similar to the gold deposits of Timmins and Porcupine in that a por phyry hydrothermal system has been superimposed on a Volcanogenic Copper-Gold Deposits carbonatized mafic flow stratigraphy. As well, a carbo nate-breccia unit (Trowell 1977; Gordanier 1975) com Again, in comparison with mineralization types of Japan posed of carbonatized, possibly ultramafic, hyaloclastite and other island arc environments we should consider carries anomalous gold in the 10-200 ppb range, with the question of Besshi-type sulphide deposits. These py- higher values in cross-cutting quartz veins. Perhaps the rite-chalcopyrite-(gold) deposits are generally associ lack of a superimposed hydrothermal system precludes ated with deep water, intermediate to mafic volcanic the development of an ore-grade deposit. However, so lit rocks and associated chemical and clastic sedimentary tle of the unit is exposed, further investigation is war rocks (Mitchell and Bell 1973; Sawkins 1976). In the pres ranted. A carbonatized mafic unit is similarly found in the ent area the Maybrun deposit (Davies 1973) may be of Goldrock camp (Blackburn 1979a), stratigraphically be this type. Other areas of comparable lithologies are the neath the felsitic units that host gold mineralization. How lower Jutten Volcanics in the area of Armit and Never ever, no porphyry body occurs close by, though the pos freeze Lakes where interbedded quartz-magnetite iron sibility of such a body at depth is not ruled out. Ultramafic stone and chert, locally with graphitic and sulphidic (py intrusions and rare flows with apparent komatiitic chemis rite, pyrrhotite, trace chalcopyrite and sphalerite) try occur at Armit Lake. They show a close spatial rela siltstone occur together with mafic volcanic amphibolite. tionship to quartz-magnetite ironstone units, both being A comparable situation occurs at the North Pines Mines likely favourable areas for gold mineralization. 24 Copper-Molybdenum Deposits Baragar, W.R.A., and McGlynn, J.C. 1976: Early Archean Basement in the Canadian Shield, A Review of the Evidence; Geological Survey of Canada, Paper 76- Porphyry copper and molybdenum deposits in the area 14, 20p. appear to be of two types. One type, such as in the Bei- 1978: On the Basement of Canadian Greenstone Belts, Discus delman Bay Pluton, is analagous to island-arc porphyry sion; Geoscience Canada, Vol. 5, p.13-15. deposits described by Lowell and Guilbert (1974). The Beard, R.C. Lateral Lake Stock (Colvine and Mccarter 1977; Page 1975: 1974 Report of the Northwestern Regional Geologist and 1979) is representative of the second type, comparable the Kenora Resident Geologist; p. 1-24 in Annual Report of to those that occur in continental margin magmatic belts the Regional and Resident Geologists, 1974, Edited by developed within continental crust (Hollister 1975). It is of E.G. Pye, Ontario Division of Mines, Miscellaneous Paper 60, 241 p. interest that lithophile element mineralization such as tin Beard, R.C., and Garratt, G.L. and tungsten occurs in a similar continental setting 1976: Gold Deposits of the Kenora Fort Frances Area, Dis (Pearce and Gale 1977) similar to the tungsten-tin occur tricts of Kenora and Rainy River; Ontario Division of Mines, rences situated at the same stratigraphic level as the Lat Mineral Deposits Circular 16, 46 p. Accompanied by Chart eral Lake molybdenum mineralization. A, Scale 1:253 440. Beard, R.C., and Rivett, S. 1977: 1976 Report of the Northwestern Regional Geologist and the Kenora Resident Geologist; p. 1-15 in Annual Report of Copper-Gold in Intrusive Rocks the Regional and Resident Geologists, 1976, Edited by C.R. Kustra, Ontario Geological Survey, Miscellaneous Pa At Chibougamau in Quebec, copper-gold mineralization per 71, 142p. is associated with shears in the anorthosite zone of the 1978:1977 Report of Northwestern Regional Geologist and Ken Dore Lake Complex marginal to the later, felsic Chiboug ora Resident Geologist, p. 1-13, in Annual Report of the Re amau Pluton (Allard 1976). The Mulcahy Lake Intrusion gional and Resident Geologists, 1977, Edited by C.R. Kus (Blackburn /nTrowell et al. 1978) is a similar differentiated tra, Ontario Geological Survey, Miscellaneous Paper 78, body, but lacking an analogue of the anorthosite zone. Al 121p. Beard, R.C., and Scott, W.R. lard (1976) considers the Chibougamau ores to be epi 1976: 1975 Report of the Northwestern Regional Geologist and genetic, but whether they are epigenetic or syngenetic, the Kenora Resident Geologist; p. 1-15 in Annual Report of the analogy with Mulcahy means that a search for cop the Regional and Resident Geologists, 1975, Edited by per-gold mineralization marginal to late felsic phases C.R. Kustra, Ontario Division of Mines, Miscellaneous Pa may be worthy of investigation. per 64, 146p. Bell, RT. 1973: Archean Sedimentation in the Midwest Superior Geotrav erse with Emphasis on the Savant Lake Area; Geotraverse Platinum and Platinoid Group Elements Summary, University of Toronto, 3 p. Blackburn, C.E. At the current high price of platinum and platinoid group 1976a: Geology of the Lower Manitou-Uphill Lakes Area, District elements, a systematic study of all the ultramafic bodies, of Kenora; Ontario Division of Mines, Geological Report especially those that show magmatic differentiation al 142,82p. Accompanied by Map 2320, Scale 1:31 680. lowing cumulate crystallization and the concentration of 1976b: Stratigraphy and Structure of Volcanic-Sedimentary As particular phases at specific stratigraphic heights within semblages, Manitou Lakes Area; p.61-64 in Geotraverse Conference Proceedings, University of Toronto, 155p. the intrusions (e.g. Mulcahy Lake Intrusion) should be 1977: Identification of Archean Calc-Alkaline Volcanic Centres in considered. the Manitou Lakes Area, Northwestern Ontario; Abstract, p.7, in Institute on Lake Superior Geology, 23rd Annual Meeting, Proceedings, edited by M.M. Kehlenbeck, S.A. Kissin, and R.H. Mitchell. 53p. 1979a: Geology of the Boyer Lake Meggisi Lake Area, District References of Kenora. Ontario Geological Survey, Open File Report 5263,134p. Accompanied by 2 maps, Scale 1:15 840. Allard, G.O. 1979b: Wabigoon Fault: A Major Structural Break in Northwest 1976: Dor6 Lake Complex and its Importance to Chibougamau ern Ontario?; Abstracts with Programs, Geological Associa Geology and Metallogeny; Quebec Department of Natural tion of Canada/Mineralogical Association of Canada, Vol.4, Resources, Document Preliminaire 368,446p. p.39. American Commission on Stratigraphic Nomenclature 1979c: Geology of the Upper Manitou Lake Area, District of Ken 1970: Code of Stratigraphic Nomenclature; The American Asso ora; Ontario Geological Survey, Report 189, 74p. Accom ciation of Petroleum Geologists, Inc., Tulsa, Oklahoma, panied by Map 2409, Scale 1:31 680. 22p. 1979d: Kawashegamuk Lake Area, District of Kenora; p.35-37 in Anhaeusser, C.R. Summary of Field Work, 1979, by the Ontario Geological 1975: Precambrian Tectonic Environments; Annual Review Earth Survey, edited by V.G. Milne, O.L. White, R.B. Barlow, and Planetary Science, Vol. 3, p.31-53. C.R. Kustra, Ontario Geological Survey, Miscellaneous Pa Armstrong, H.S. per 90,245p. 1951: Geology of Echo Township; Ontario Department of Mines, in preparation: Geology of the Manitou Lakes Area, Stratigraphy Annual Report for 1950, Vol. 59 pt.5, p. 1-40. Accompanied and Structure; Ontario Geological Survey Report. by Map No. 1950-1, Scale 1:12 000. 25 SAVANT LAKE—CROW LAKE Blackburn, C.E., Trowell, N.F., and Edwards, G.R. Collins, W.H. 1978: Bilateral Symmetry of Archean Volcano-Sedimentary Se 1910: A Geological Reconnaissance of the Region Traversed by quences, Western Wabigoon Belt, Ontario; Abstract with the National Transcontinental Railway Between Lake Nipi Programs, Geological Association of Canada/Geological gon and Clay Lake, Ontario; Publication Number 1059 in Society of America/Mineralogical Association of Canada, Geological Survey of Canada Summary Report for 1909, Toronto, Vol. 3, p.367. p.1-67. Accompanied by Maps No.993, No.1061, Scale Bond.W.D. 1:253 440. 1977: Geology of McCubbin, Poisson, and McGillis Townships Colvine, A.C., and McCarter, P. (Savant Lake Area) District of Thunder Bay; Ontario Division 1977: Geology and Mineralization of the Lateral Lake Stock, Dis of Mines, Geological Report 160, 78p. Accompanied by trict of Kenora; p.205-208 in Summary of Field Work, 1977, Map 2357, Scale 1:31,680. by the Geological Branch, edited by V.G. Milne, O.L. White, 1978: Geology of the Houghton-Hough Lakes Area (Savant Lake R.B. Barlow, and J.A. Robertson, Ontario Geological Sur Area), District of Thunder Bay; Ontario Geological Survey vey, Miscellaneous Paper 75, 208p. Open File Report 5237,191 p. Accompanied by Map P.933, Colvine, A.C. and Sutherland, l.G. Scale 1:15 840. 1979: The Geology and Mineralization of the Pickerel Arm, Ca 1979: Geology of Conant, Jutten, and Smye Townships (Savant noe Lake and High Lake Bodies; p.233-243 in Summary of Lake Area), District of Thunder Bay; Ontario Geological Field Work, 1979, by the Geological Branch, edited by V.G. Survey, Report 182, 113p. Accompanied by Map 2398, Milne, O.L. White, R.B. Barlow, and C.R. Kustra, Ontario Scale 1:31 680. Geological Survey, Miscellaneous Paper 90,245p. Breaks, F.W. Covello, L. in preparation: Sioux Lookout-Armstrong Sheet; Ontario Geologi 1971: The Structure, Stratigraphy, and Petrology of the North cal Survey, Geological Compilation Map, Scale 1:253 440. End of Abitibi Block Seven, Sturgeon Lake, Ontario; Unpub. Breaks, F.W., and Bond, W.D. B.Se. thesis, Lakehead University, Thunder Bay, Ontario, 1975: Operation Kenora-Ear Falls, District of Kenora; p. 19-33 in 66p. Summary of Field Work, 1975, by the Geological Branch, Cuddy, R.G. and Clifford, P.M. edited by V.G. Milne, D.F. Hewitt, K.D. Card, and J.A. Rob 1972: Effect of a Rigid Ultrabasic Sill on Deformation in Adjacent ertson, Ontario Division of Mines, Miscellaneous Paper 63, Rocks, Kakagi Lake N.W. Ontario; Abstract for Paper 5 in 158p. 18th Annual Institute on Lake Superior Geology, edited by 1976: Operation Minniss-Tully Lakes, District of Kenora; p. 16-26 W.I. Rose. in Summary of Field Work, 1976, by the Geological Branch, Davies, J.C. edited by V.G. Milne, W.R. Cowan, K.D. Card and J.A. Rob 1973: Geology of the Atikwa Lake area, District of Kenora; On ertson, Ontario Division of Mines, Miscellaneous Paper 67, tario Division of Mines, Geological Report 111, 57p. Ac 183p. companied by Map 2273, Scale 1:31 680. 1977: English River Subprovince (Marchington Lake Area), Dis Davies, J.C. and Morin, J.A. trict of Kenora; p. 18-28 in Summary of Field Work, 1977, by 1976: Geology of the Cedartree Lake Area, District of Kenora; the Geological Branch, edited by V.G. Milne, O.L. White, Ontario Division of Mines, Geological Report 134, 52p. Ac R.B. Barlow, and J.A. Robertson, Ontario Geological Sur companied by Map 2319, scale 1:31 680. vey, Miscellaneous Paper 75,208p. Davies, J.C., and Pryslak, A.P. Breaks, F.W., Bond, W.D., and Stone, D. 1967: Kenora-Fort Frances Sheet, Kenora and Rainy River Dis 1978: Preliminary Geological Synthesis of the English River Sub tricts; Ontario Department of Mines, Geological Compila province, Northwestern Ontario and its Bearing upon Min tion Series, Map 2115, scale 1:253 440. Geological Compi eral Exploration; Ontario Geological Survey, Miscellaneous lation 1963-1965. Paper 72, 55p. Accompanied by Map P. 1971, Scale 1:253 Davies, J.C., Pryslak, A.P., and Pye, E.G. 440. 1970: Sioux Lookout-Armstrong Sheet, Kenora and Thunder Bay Brooks, C., and Gelinas, L. Districts; Ontario Department of Mines, Geological Compi 1977: The Relationship of Base Metal Mineralization to Chemos- lation Series, Map 2169, Scale 1:253 440. Geological Com tratigraphic Divisions in Volcanic Rocks of Canadian Ar pilation 1965-1966. chean Greenstone Belts; Research Paper 77-1, Mineral Ex Davies, J.C., and Watowich, S.N. ploration Research Institute, Montreal, Quebec. 1958: Geology of the Populus Lake Area; Ontario Department of Burke, K., Dewey, J.F., and Kidd, W.S.F. Mines, Annual Report for 1956, Vol. 65, part 4, p.1-24. Ac 1976: Dominance of Horizontal Movements, Arc and Microconti- companied by Map 1956-3, Scale 1:31 680. nental Collisons During the Later Permobile Regime; p.113- Davis, D.W., Blackburn, C.E., Trowell, N.F., and Edwards, G.R. 129 /nthe Early History of the Earth, ed. B.F. Windley, Wiley, in preparation: Geochronology of the Savant-Crow Lakes Area, 619p. Western Wabigoon Subprovince, northwestern Ontario; in Burwash, E.M. Summary of Geochronology Research 1978-1979, edited 1934: Geology of the Kakagi Lake Area; Ontario Department of by E.G. Pye, Ontario Geological Survey, Miscellaneous Pa Mines, Annual Report for 1933, Vol. 42, pt.4, p.41-92. Ac per 92. companied by Map 42b, Scale 1:63 360. Edwards, G.R. Chisholm, E.O. 1976: Geology of the Pipestone Lake (North) Area, District of 1951: Recent Activities in Sioux Lookout Area; Ontario Depart Kenora; Ontario Division of Mines, Open File Report 5194, ment of Mines, Preliminary Report 1951-1. Accompanied 87p. Accompanied by map, scale 1:15 840. by Index Map, scale 1:31 680, (also published in The Pre 1978: Geology of the Pipestone Lake (South) Area, District of cambrian, Vol. 24, No.7, p.10-14). Rainy River; Ontario Geological Survey, Open File Report Coker, W.B., and Nichol, l. 5247,92p. Accompanied by map, scale 1:15 840. 1975: The Relation of Lake Sediment Geochemistry to Minerali in preparation: Geology of the Straw Lake Area, Districts of Rainy zation in the Northwest Ontario Region of the Canadian River and Kenora; Ontario Geological Survey, Report. Shield; Economic Geology, Vol. 70, p.202-218. 26 Edwards, G.R. and Sutcliffe, R.H. Gordanier, W.D. 1977: Straw Lake Area, Districts of Rainy River and Kenora; On 1975: Geochemistry of a Carbonate Breccia Unit in N.W. Ontar tario Division of Mines, Preliminary Map P. 1243, Geological io; Unpub. B.Se. thesis, University of Ottawa, Ottawa, On Series, Scale 1:15 840. Geology 1975. tario, 18p. Ferguson, S.A., Brown, D.D., Davies, J.C., and Pryslak, A.P. Gorman, B.E., Pearce, T.H., and Birkett, T.C. 1970: Red Lake-Birch Lake Sheet, Kenora District; Ontario De 1978: On the Structure of Archean Greenstone Belts; Precam partment of Mines, Geological Compilation Series, Map brian Research, Vol.6, p.23-41. 2175, scale 1:253 440. Geological compilation 1966-1967. Harding, W.D. Franklin, J.M. 1951: Geology of the Gullwing Lake-Sunstrum Area; Ontario De 1975: Metallogenic Relations at Sturgeon Lake; Proceedings partment Mines, Annual Report for 1950, Vol. 59, pt. 4, p.1- 1975 Geotraverse Workshop, University of Toronto, p.39-1 29. Accompanied by Map 1950-2, Scale 1:63 360. to 39-25. Hinzer, J.C. 1976: Role of Laharic Breccia in Genesis of Volcanogenic Mas 1977: Geological and Geochemical Survey of Lyon Lake and sive Sulphide Deposits; Geological Survey of Canada, Re Creek Ore Zones, Sturgeon Lake, Northwestern Ontario; port of Activities, Part A, Paper 76-1 A, p.293-300. Unpub. M.Se. thesis, University of Western Ontario, Lon 1977: Stratigraphic and Chemical Relations, South Sturgeon don, Ontario, 94p. Lake Area; Proceedings 1977 Geotraverse Workshop, Uni Hoad, J.S. versity of Toronto, p. 118-120. 1970: Bell Lake Syenite Complex; unpublished B.Se. thesis, Uni Franklin, J.M., Gibb, W., Tamman, A., and Kerr, B. versity of Waterloo, Waterloo, Ontario, 32p. 1973: The Mattabi Deposit; Canadian Institute of Mining and Me Hodgson, C. J. and Lydon, J. W. tallurgy, Geological Division Annual Field Trip, Guidebook, 1977: Geological Setting of Volcanogenic Massive Sulphide De 19p. posits and Active Hydrothermal Systems, Some Implica Franklin, J.M., Gibb, W., Poulsen, K.H., and Severin, P. tions for Exploration; Canadian Institute of Mining and Me 1977: Archean Metallogeny and Stratigraphy of the South Stur tallurgy, Bulletin, Volume 70, Number 786, p.95-106. geon Lake Area; Mattabi Trip, 23rd Annual Meeting, Insti Hollister, V.F. tute on Lake Superior Geology, 73p. 1975: An Appraisal of the Nature and Source of Porphyry Cop Franklin, J.M., Kasarda, J., and Poulsen, K.H. per Deposits; Minerals Science and Engineering, Vol.7, 1975: Petrology and Chemistry of the Alteration Zone of the Mat p.225-233. tabi Massive Sulphide Deposit; Economic Geology, Vol.70, Horwood, H.C. p. 163-179. 1938a: Geology of the Superior Junction Sturgeon Lake Area; Fraser, N.H.C. Ontario Department of Mines, Annual Report for 1937, 1945: Geology of the Whitefish Bay Area, Lake of the Woods; Vol.4, pt.6, p.1-25. Accompanied by Map 46d, Scale 1:126 Ontario Department of Mines, Annual Report for 1943, Vol. 720 and Map 46e, Scale 1:47 520. 52, pt.4, p. 1-19. Accompanied by Map 52c, Scale 1:63 1938b: Geology at the Darkwater Mine; Ontario Department of 360. Mines, Annual Report for 1937, Vol.4, pt.6, p.26-39. Priske, P. Hudec, P.P. 1974: The Beidelman Bay Copper Porphyry Deposit; Unpub. 1965: Highstone Lake Miniss Lake Area, Districts of Kenora B.Se. thesis, Lakehead .University, Thunder Bay, Ontario, and Thunder Bay; Ontario Department of Mines, Geological 108p. Report 32, 28p. Accompanied by Maps 2063, 2064, Scale Funk.G.H. 1:63 360. 1973: Petrographic and Chemical Study of Granitoid Pheno- Jensen, L.S. clasts from Selected Archean Conglomerates; Unpub. 1976: A new Cation Plot for Classifying Subalkalic Volcanic B.Se. thesis, Brock University, St. Catharines, Ontario, 36p. Rocks; Ontario Division of Mines, Miscellaneous Paper 66, Gelinas, L., Brooks C., and Trzcienski, W.E., Jr. 22p. 1976: Archean Variolites Quenched Immiscible Liquids?; Johnston, F.J. Canadian Journal of Earth Science, Vol.13, p.210-230. 1969: Geology of the Western Minnitaki Lake Area; Ontario De Glikson, A.Y. partment of Mines, Geological Report 75, 28p. Accompa 1978: On the Basement of Canadian Greenstone Belts; Geosci nied by Map 2155, Scale 1:31 680. ence Canada, Vol.5, p.3-12. 1972: Geology of the Vermilion-Abram Lakes Area, District of Goodwin, A.M. Kenora; Ontario Department of Mines, Geological Report 1965: Preliminary Report on Volcanism and Mineralization in the 101, 51 p. Accompanied by Maps 2242 and 2243, Scale Lake of the Woods Manitou Lake Wabigoon Region of 1:31 680. Northwestern Ontario; Ontario Department of Mines, Pre Karvinen, W.O. liminary Report 1965-2, 63p. Accompanied by Chart, Scale 1978: The Porcupine Camp a Model for Gold Exploration in 1:253 440. the Archean; Canadian Mining Journal, Vol.99, No.9, p.48- 1968: Archean Protocontinental Growth and Early Crustal History 53. of the Canadian Shield; 23rd International Geological Con Kasarda, J. gress, Vol.1, p.69-89. 1973: Wall Rock Alteration and Trace Element Geochemistry of 1970: Archean Volcanic Studies in the Lake of the Woods the Footwall Rocks of the Mattabi Deposit, Sturgeon Lake Manitou Lake Wabigoon Region of Western Ontario; On Area; Unpub. B.Se. thesis, Lakehead University, Thunder tario Department of Mines, Open File Report 5042. Bay, Ontario, 103p. Goodwin, A.M. and West, G.F. Kaye, L. 1975: The Superior Geotraverse Project; p.1-1 to 1-22 in Pro 1973: Rowan Lake Area, District of Kenora; Ontario Division of ceedings of the Geotraverse Project, 1975, University of To Mines, Preliminary Map P.831, Geological Series, Scale ronto. 1:15840. Geology 1972. 27 SAVANT LAKE—CROW LAKE 1974a: Crow Lake Area (Eastern Part), District of Kenora; Ontario Nielsen, P.E. Division of Mines, Preliminary Map P.921, Geological Se 1974: The Geochemistry of the Lyon Lake-Claw Lake Sulphide ries, scale 1:15 840. Geology 1973. Bearing Graphitic Shale, Sturgeon Lake, Ontario; Unpub. 1974b: Crow Lake Area (Western Part), District of Kenora; On B.Se. thesis, Lakehead University, Thunder Bay, Ontario, tario Division of Mines, Preliminary Map P.920, Geological 99p. Series, scale 1:15 840. Geology 1973. ODM Kusmirski, RT. 1974: Ontario Mineral Map; Ontario Division of Mines, Map 2310, 1977: Petrology and Geochemistry of the Heron Lake Stock, Su scale 1:1 584 000. Information current to December 1973. perior Province, Wabigoon Subprovince, Northwestern On Page, R.O. tario; Unpub. B.Se. thesis, McMaster University, Hamilton, 1978a: Geochemistry of the Archean Basalt-Andesite Suite of Ontario, 78 p. Minnitaki Lake, Northwestern Ontario; Abstracts with Pro Langford, F.F., and Morin, J.A. grams, Joint Annual Meeting, Geological Association of 1976: The Development of the Superior Province of Northwest Canada/Geological Society of America/Mineralogical Asso ern Ontario by Merging Island Arcs; American Journal of ciation of Canada, Toronto, 1978, Vol. 3, p.467 Science, Vol.276, p. 1023-1034. 1978b: Zarn Lake Area, District of Kenora; p.45-48 in Summary Lavin, O.P. of Field Work, 1978, by the Ontario Geological Survey, edi 1976: Lithogeochemical Discrimination Between Mineralized ted by V.G. Milne, O.L. White, R.B. Barlow and J.A. Robert and Unmineralized Cycles of Volcanism in the Sturgeon son, Ontario Geological Survey, Miscellaneous Paper 82, Lake and Ben Nevis Areas of the Canadian Shield; Unpub. 235p. M.Se. thesis, Queen©s University, Kingston, Ontario, 249p. 1979: Lateral Lake Area, District of Kenora; p.92-96 in Summary Lefebvre, J.J., Naert, K.A., and Gasparini, C.E. of Field Work, 1979, by the Ontario Geological Survey, edi 1978: Coexistence of Sillimanite, Andalusite, and Kyanite in Fel ted by V.G. Milne, O.L. White, R.B. Barlow, and C.R. Kustra, sic to Intermediate Metavolcanics in the Savant Lake Area, Ontario Geological Survey, Miscellaneous Paper 90,245p. District of Thunder Bay, Ontario; Abstracts with Programs, Page, R.O. and Clifford, P.M. Joint Annual Meeting Geological Association of Canada/ 1977: Physical Volcanology of an Archean Vent Complex, Minni Geological Society of America/Mineralogical Association of taki Lake Area, Northwestern Ontario; Geological Survey of Canada, Toronto, 1978, Vol.3, p.442-443. Canada, Report of Activities, Paper 77-1 A, p.441-443. Lowell, J.D., and Guilbert, J.M. Palonen, P.A. and Speed, A.A. 1974: Variations in Zoning Patterns in Porphyry Ore Deposits; 1977: Sandybeach Lake Area, District of Kenora, Patricia Por Canadian Institute of Mining and Metallurgy Bulletin, Vol.67, tion; p.55-56 in Summary of Field Work, 1977, by the Geo p.99-109. logical Branch, edited by V.G. Milne, O.L. White, R.B. Bar Mackasey, W.O., Blackburn, C.E., and Trowell, N.F. low, and J.A. Robertson, Ontario Geological Survey, 1974: A Regional Approach to the Wabigoon-Quetico Belts and Miscellaneous Paper 75,208p. Its Bearing on Exploration in Northwestern Ontario; Ontario Pearce, J.A. and Gale, G.H. Division of Mines, Miscellaneous Paper 58,30p. 1977: Identification of Ore-Deposition Environment from Trace- Mcconnell, J.W. Element Geochemistry of Associated Igneous Host Rocks; 1976: Geochemical Dispersion in Wallrocks of Archean Massive p. 14-24 in Volcanic Processes in Ore Genesis, Special Sulphide Deposits; Unpub. M.Se. thesis, Queen©s Universi Publication No. 7, Geological Society of London, 188p. ty, Kingston, Ontario, 230p. Pettijohn, F.J. Mcinnes, W. 1934: Conglomerate of Abram Lake, Ontario, and its Extensions; 1900: Explorations and Surveys, Rainy River District, Ontario; Geological Society of America, Bulletin, Vol.45, p.479-506. p.115A-122A in Geological Survey of Canada, Annual Re 1935: Stratigraphy and Structure of Vermilion Township, District port, Vol. 12, 1899, Report A, 224p. Accompanied by Map of Kenora, Ontario; Geological Society of America, Bulletin, 663, Scale 1:253 440. Vol.46, P.1891-1908. McMaster, G.E. 1936: Geology of East Bay, Minnitaki Lake, District of Kenora, 1978: Archean Volcanism and Geochemistry, Washeibemaga- Ontario; Journal of Geology, Vol.44, p.341-357. Thundercloud Lakes Area, Wabigoon Subprovince, Supe 1937: Early Precambrian Geology and Correlational Problems of rior Province, Northwest Ontario; Unpub. M.Se. thesis, the Northern Subprovince of the Lake Superior Region; Ge McMaster University, Hamilton, Ontario, 222p. ological Society of America, Bulletin, Vol.48, p. 153-202. Mitchell, A.H., and Bell, J.D. 1939: "Coutchiching" of Thunder Lake, Ontario; Geological So 1973: Island-Arc Evolution and Related Mineral Deposits; Jour ciety of America, Bulletin, Vol.50, p.761-775. nal of Geology, Vol.81, p.381 -405. 1972: The Archean of the Canadian Shield: A Resume; p.131- Moore, E.S. 149 in Studies in Mineralogy and Precambrian Geology, 1910: Lake Savant Iron Range Area; Ontario Bureau of Mines, edited by B.R. Doe and D.K.Smith, Geological Society of Vol.19, pt.1, p. 173-192. Accompanied by Map, Scale 1:126 America, Memoir 135,348p. 720. Pyke, D.R. 1929: Lake Savant Area, District of Thunder Bay; Ontario Depart 1975: On the Relationship of Gold Mineralization and Ultramafic ment of Mines, Annual Report for 1928, Vol.37, pt.4, p.53- Volcanic Rocks in the Timmins Area; Ontario Division of 82. Accompanied by Map 37j, Scale 1:126 720. Mines, Miscellaneous Paper 62,23p. Moorhouse, W.W. Reid, J. 1941: Geology of the Eagle Lake Area; Ontario Department of 1978: Archean Variolitic Lavas; Unpubl. B.Se. Thesis, Queen©s Mines, Annual Report for 1939, Vol.48, pt.4, p. 1-31, Accom University, Kingston, Ontario, 69p. panied by Map 48d, scale 1:63 360. Ridler, R. Nesbitt, R.W., and Sun, S.S. 1966: Petrographic Study of a Crow Lake Ultrabasic Sill, Keewa 1976: Geochemistry of Archean Spinifex-Textured Peridotites tin Volcanic Belt, N.W. Ontario; Unpubl. M.A.Sc. Thesis, and Magnesian and Low-Magnesian Tholeiites; Earth and University of Toronto, Toronto, 107 p. Plantetary Science Letters, Vol.31, p.433-453. 28 Rittenhouse, G. Sopuck, V.J. 1936: Geology of a Portion of the Savant Lake Area, Ontario; 1977: A Lithogeochemical Approach in the Search for Areas of Journal of Geology, Vol.44, p.451-478. Felsic Volcanic Rocks Associated with Mineralization in the Sage, P.P., Breaks, F.W., Stott, G.M., and Mcwilliams, G.M. Canadian Shield; Unpub. Ph.D. thesis, Queen©s University, 1973a: Operation Ignace-Armstrong, Districts of Kenora, Rainy Kingston, Ontario, 296p. River, and Thunder Bay; p. 38-70 in Summary of Field Work, Speed, A.A. 1973, by the Geological Branch, edited by V.G. Milne, D.F. 1978:1977 Report of Sioux Lookout Resident Geologist; p.28-36 Hewitt, and W.J. Wolfe, Ontario Division of Mines, Miscella in Annual Report of the Regional and Resident Geologists neous Paper 56, 202p. 1977, edited by C.R. Kustra, Ontario Geological Survey, 1973b: Operation Ignace-Armstrong, Pashkokagan-Caribou Miscellaneous Paper 78,121 p. Lakes Sheet; Ontario Division of Mines, Preliminary Map Talbot, C.J. P.962, Geological Series, Scale 1:126 720. 1973: A Plate Tectonic Model for the Archean Crust; Transac Sato, T. tions, Royal Philosophical Society, London, Vol. A273, 1977: Kuroko Deposits Their Geology, Geochemistry and Ori p.413-427. gin; p. 153-161 in Volcanic Processes in Ore Genesis, Pro Tanton, T. L. ceedings, Joint Meeting Volcanic Studies Group, Geologi 1940: Watcomb, Kenora and Rainy River Districts, Ontario; Geo cal Society of London Institution of Mining and Metallurgy, logical Survey of Canada, Map 557A, Scale 1:253 000. London, January, 1976, Special Publ. No. 7, Geological So Teal, D.R. and Walker, R.G. ciety of London, 188p. 1977: Stratigraphy and Sedimentology of the Archean Manitou Satterly, J. Group, Northwestern Ontario; p.181-184 in Report of Activi 1941: Pillow lavas from the Dryden-Wabigoon Area, District of ties, Part A, Geological Survey of Canada, Paper 77-1 A. Kenora, Ontario; Contributions to Canadian Mineralogy, Thomson, J.E. 1941, University of Toronto Studies, Geological Series, 1934: Geology of the Manitou-Stormy Lakes Area; Ontario De No.46, p.119-136. partment of Mines, Annual Report for 1933, Vol.42, pt.4, 1943: Geology of the Dryden-Wabigoon Area; Ontario Depart p.1-40. Accompanied by Map 42c, Scale 1:63 360. ment of Mines, Annual Report for 1941, Vol.50, part 2, p.1- 1936: Gold Deposits of the Belt Extending from Manitou Lake to 67. Accompanied by Map 50e, scale 1:63 360. Lake of the Woods; Canadian Institute of Mining and Metal 1960. Geology of the Dyment Area, Ontario Department of lurgy, Transactions, Vol.39, p.686-701. Mines, Annual Report for 1960, Vol.69, part 6, p.1-32. Ac 1942: Some Gold Deposits near Goldrock, Upper Manitou Lake; companied by Map 1960h, scale 1:31 680. Ontario Department of Mines, Annual Report for 1938, Sawkins, F.J. Vol.47, pt.6, p.1-10. Accompanied by Map 47k, Scale 1:4 1976: Massive Sulphide Deposits in Relation to Geotectonics; 800. p.221 - 240 in Metallogeny and Plate Tectonics, edited by Trowell, N.F. D.F. Strong, Geological Association of Canada, Special Pa 1970: Geology of the Watcomb Area, District of Kenora, Ontario per No. 14,660p. Department of Mines and Northern Affairs, Geological Re Schwerdtner, W.M., Stone, D., Osadetz, K., Morgan J., and Stott, port 88, 28p. Accompanied by Map 2209, Scale 1:31 680. G.M. 1974a: Geology of the Bell Lake Sturgeon Lake Area, Districts 1979: Granitoid Complexes and the Archean Tectonic Record in of Kenora and Thunder Bay; Ontario Division of Mines, Ge the Southern Part of Northwestern Ontario; Canadian Jour ological Report 114, 67p. Accompanied by Maps 2268 and nal of Earth Sciences, Vol.16, p. 1965-1977. 2269, Scale 1:31 680. Shegelski, R.J. 1974b: Geology of the Glitter Lake Area, District of Thunder Bay; 1975: Geology and Geochemistry of Iron Formations and their Ontario Division of Mines, Geological Report 120, 31 p. Ac Host Rocks in the Savant Lake Sturgeon Lake Green companied by Map 2284, Scale 1:31 680. stone Belts; Proceedings 1975 Geotraverse Workshop, 1976: Geology of the Quest Lake Area, Districts of Kenora and University of Toronto, p.34-1 to 34-21. Thunder Bay; Ontario Division of Mines, Geological Report 1976: Geology and Geochemistry of Archean Iron Formations 154,60p. Accompanied by Map 2335, Scale 1:31 680. and their Relation to Reconstructed Terrains in the Stur 1977: Geology of the Squaw Lake Sturgeon Lake Area, Dis geon and Savant Lakes Greenstone Belts; Proceedings trict of Thunder Bay; Ontario Division of Mines, Open File 1976 Geotraverse Workshop, University of Toronto p. 109- Report 5225, 230p. Accompanied by Map P.968, Scale 119. 1:15840. 1978: Stratigraphy and Geochemistry of Archean Iron Forma 1978: Geology of the Sturgeon Lake Chevrier Township Area, tions in the Sturgeon Lake Savant Lake Greenstone Ter District of Thunder Bay; Ontario Division of Mines, Open rain, Northwestern Ontario; Unpub. Ph.D. Thesis, University File Report 5250, 97p. Accompanied by Maps P. 1495 and of Toronto, Toronto, Ontario, 251 p. P.1496, Scale 1:15 840. Shegelski, R.J. and Bell, RT. in preparation: Geology of the Sturgeon Lake Area, Districts of 1976: Coarse Clastic Facies of the Savant Lake and Sturgeon Kenora and Thunder Bay; Ontario Geological Survey, Re Lake Greenstone Belts; Proceedings 1976 Geotraverse port. Workshop, University of Toronto, p.96-108. Trowell, N.F., Blackburn, C.E., Edwards, G. and Bartlett, J.R. Shklanka, R. 1978: Savant Lake Crow Lake Special Project, Districts of 1967: Copper, Nickel, Lead and Zinc Deposits of Ontario; On Thunder Bay and Kenora; p.28-44 in Summary of Field tario Department of Mines, Mineral Resources Circular 12, Work, 1978, by the Ontario Geological Survey, edited by 394p. V.G. Milne, O.L. White, R.B. Barlow, J.A. Robertson, Ontario Skinner, R. Geological Survey, Miscellaneous Paper 82, 235p. 1969: Geology of the Sioux Lookout Map-Area, Ontario, a Part of Trowell, N.F., Blackburn, C.E., Edwards, G., and Sutcliffe, R.H. the Superior Province of the Precambrian Shield; Geologi 1977: Savant Lake Crow Lake Special Project, Districts of cal Survey of Canada, Paper 68-45, 10p. Accompanied by Thunder Bay and Kenora; p.29-50 in Summary of Field Map 14-1968, Scale 1:253 440. 29 SAVANT LAKE—CROW LAKE Work, 1977, by the Geological Branch, edited by V.G. Walker, R.G. and Pettijohn, F.J. Milne, O.L. White, R.B. Barlow, and J.A. Robertson, Ontario 1971: Archean Sedimentation: Analysis of the Minnitaki Basin, Geological Survey, Miscellaneous Paper 75, 208p. Northwestern Ontario, Canada; Geological Society of Trusler, J.R. America, Bulletin, Vol.82, p.2099-2130. 1974: Farrington Lake Area, District of Kenora; p.41-47 in Sum Webb, J.K. mary of Field Work, 1974 by the Geological Branch, edited 1948: Geology of the Lunward Gold Mine, Echo Township, Dis by V.G. Milne, D.F. Hewitt, and K.D. Card, Ontario Division trict of Kenora, Ontario; Unpub. M.A. Thesis, University of of Mines, Miscellaneous Paper 59, 206p. Toronto, Toronto, Ontario, 32p. 1975: Farrington Lake Area, District of Kenora; Ontario Division Wilson, H.D.B., Morrice, M.G., and Ziehlke, D.V. of Mines, Preliminary Map P.996, Scale 1:15 840. 1974: Archean Continents; Geoscience Canada, Vol.1, No. 3, Turner, C.C. and Walker, R.G. p. 12-20. 1973: Sedimentology, Stratigraphy, and Crustal Evolution of the Young, G.M. Archean Greenstone Belt near Sioux Lookout, Ontario; 1978: Some Aspects of the Evolution of the Archean Crust; Canadian Journal of Earth Science, Vol.10, p.817-845. Geoscience Canada, Vol.5, p. 140-149. Ueno, H. Zalnieriunas, R.V. 1975: Duration of the Kuroko Mineralization Episode; Nature, 1978: A Study of Four Ultramafic Intrusive Bodies Found North of Vol.253, p.428-429. Post Lake, N.W. Ontario; Unpub. B.Se. Thesis, Queen©s Walker, R.G. University, Kingston, Ontario, 34p. 1975: Generalized Facies Models for Resedimented Conglomer ates of Turbidite Association; Geological Society of Amer ica Bulletin, Vol.86, p.737-748. 30 Chart A Savant Lake-Crow Lake Metavolcanic-Metasedimentary Belt 30' 90C LEGEND SYMBOLS Alkalic Intrusive Rocks Geological boundary Syenite Anticline, syncline, with plunge Felsic Intrusive Rocks Fault Stratigraphic top; pillow and sedimentary structures Mafic and Ultramafic Intrusive Rocks Scale 1 6,336,000 or 1 inch to 100 miles Metavolcanics Intermediate and felsic metavolcanics Mafic metavolcanics 500 r CHART A PRELIMINARY STRATIGRAPHIC UNITS AND STRUCTURAL GEOLOGY SAVANT LAKE - CROW LAKE METAVOLCANIC - METASEDIMENTARY BELT Districts of Kenora, Rainy River, and Thunder Bay Scale 1 : 506,880 8 16 24 32 Miles Kilometres 10 10 20 30 40 50 Kilometres 49' 30 93 30