THESE TERMS GOVERN YOUR USE OF THIS DOCUMENT

Your use of this Geological Survey document (the “Content”) is governed by the terms set out on this page (“Terms of Use”). By downloading this Content, you (the “User”) have accepted, and have agreed to be bound by, the Terms of Use.

Content: This Content is offered by the Province of Ontario’s Ministry of Northern Development and Mines (MNDM) as a public service, on an “as-is” basis. Recommendations and statements of opinion expressed in the Content are those of the author or authors and are not to be construed as statement of government policy. You are solely responsible for your use of the Content. You should not rely on the Content for legal advice nor as authoritative in your particular circumstances. Users should verify the accuracy and applicability of any Content before acting on it. MNDM does not guarantee, or make any warranty express or implied, that the Content is current, accurate, complete or reliable. MNDM is not responsible for any damage however caused, which results, directly or indirectly, from your use of the Content. MNDM assumes no legal liability or responsibility for the Content whatsoever.

Links to Other Web Sites: This Content may contain links, to Web sites that are not operated by MNDM. Linked Web sites may not be available in French. MNDM neither endorses nor assumes any responsibility for the safety, accuracy or availability of linked Web sites or the information contained on them. The linked Web sites, their operation and content are the responsibility of the person or entity for which they were created or maintained (the “Owner”). Both your use of a linked Web site, and your right to use or reproduce information or materials from a linked Web site, are subject to the terms of use governing that particular Web site. Any comments or inquiries regarding a linked Web site must be directed to its Owner.

Copyright: Canadian and international intellectual property laws protect the Content. Unless otherwise indicated, copyright is held by the Queen’s Printer for Ontario.

It is recommended that reference to the Content be made in the following form: Stott, G.M. 2008. Precambrian of the and lowlands region interpreted from aeromagnetic data – west sheet; Ontario Geological Survey, Preliminary Map P.3597–Revised, scale 1:500 000.

Use and Reproduction of Content: The Content may be used and reproduced only in accordance with applicable intellectual property laws. Non-commercial use of unsubstantial excerpts of the Content is permitted provided that appropriate credit is given and Crown copyright is acknowledged. Any substantial reproduction of the Content or any commercial use of all or part of the Content is prohibited without the prior written permission of MNDM. Substantial reproduction includes the reproduction of any illustration or figure, such as, but not limited to graphs, charts and maps. Commercial use includes commercial distribution of the Content, the reproduction of multiple copies of the Content for any purpose whether or not commercial, use of the Content in commercial publications, and the creation of value-added products using the Content.

Contact:

FOR FURTHER PLEASE CONTACT: BY TELEPHONE: BY E-MAIL: INFORMATION ON The Reproduction of MNDM Publication Local: (705) 670-5691 the EIP or Content Services Toll Free: 1-888-415-9845, ext. 5691 [email protected] (inside , United States) The Purchase of MNDM Publication Local: (705) 670-5691 MNDM Publications Sales Toll Free: 1-888-415-9845, ext. 5691 [email protected] (inside Canada, United States) Crown Copyright Queen’s Printer Local: (416) 326-2678 Toll Free: 1-800-668-9938 [email protected] (inside Canada, United States)

94°W 93°W 92°W 91°W 90°W 89°W 88°W 87°W Table 1. of Precambrian rocks, Phanerozoic ultrabasic intrusions and kimberlite pipes. MARGINAL NOTES between the two superterranes and between the Island Lake and Oxford– Kimberlite pipes in the James Bay Lowland (Sage 2000) are spatially Corkery, M.T., Cameron, H.D.M., Lin, S., Skulski, T., Whalen, J.B. and Rayner, N. and Stott, G.M. 2005. Discrimination of Archean domains in Stott, G.M. and Rainsford, D.R.B. 2006. The Precambrian geology abc Stull domains (see Figure 1). Later, Proterozoic (circa 1822 Ma and 1100 associated with Paleoproterozoic mafic (diabase) dikes (Stott 2003). Stern, R.A. 2000. Geological investigations in the Knee Lake belt the Sachigo Subprovince: a progress report on the geochronology; in underlying the James Bay and as interpreted 57°N LEGEND Map Rock Type Reference UTM UTM UTM Crystallization Maximum Inherited Metamorphic ЄNd DePaolo Ma) carbonatitic complexes (Sage 1991, p.685) intruded close to these Most notably the circa 156 to 180 Ma (Jurassic age) Attawapiskat (parts of NTS 53L); in Report of Activities 2000, Industry, Summary of Field Work and Other Activities 2005, Ontario Geological from aeromagnetic data and a revised terrane map for northwestern The relatively flat-lying Hudson Bay and James Bay lowlands form a broad, No. zone east north Age (Ma) Deposition Age (Ma) Age (Ma) Nd Model faults, implying subsequent post-Archean reactivation of these faults. cluster of kimberlites is mainly aligned along one of the northwest-trending Trade and Mines, Manitoba Geological Survey, p.129-136. Survey, Open File Report 6172, p.10-1 to 10-21. Ontario; in Summary of Field Work and Other Activities 2006, Ontario PHANEROZOIC = dominantly carbonate, Paleozoic to Mesozoic cover over a significant Age (Ma) Age (Ga) Matachewan dikes. Further west, the kimberlite pipes of the Kyle Lake Geological Survey, Open File Report 6192, p.13-1 to 13-10. portion of the Precambrian rocks in . This has impeded kimberlite group are approximately 1100 Ma in age (comparable to David, J., Parent, M., Stevenson, R., Nadeau, P. and Godin, L. 2002. La Reed, L.E. and Sinclair, I.G.L. 1991. The search for kimberlite in the James 1 quartz-rich wacke 1 15 503609 5995692 2863.2±0.7 our understanding of the Precambrian geology and tectonic framework North Caribou Terrane CENOZOIC Keweenawan intrusions along a northward extension of the Trans- séquence supracrustale de Porpoise Cove, région d'Inukjuak : un Bay Lowlands of Ontario; Canadian Institute of Mining and Metallurgy Thurston, P.C., Osmani, I.A. and Stone, D. 1991. Northwestern Superior Ontario Geological Survey 2 biotite granite 15 2723±6 across this region of Ontario and its relation to adjacent areas in Manitoba 1 513188 5992377 57°N Superior Tectonic Zone (Sage 1991)). They are more widely scattered in exemple unique de croûte paléo-archéenne (ca 3.8 Ga) dans la Bulletin, v.84, no.947, p.132-139. Province: review and terrane analysis; in , Ontario 57°N and Québec. Consequently, this set of maps is designed to provide an The central core of the North Caribou terrane (NCT) shows limited 3 quartz+feldspar porphyry 1 15 518939 6047828 2717±3 a southward direction but the individual pipes show a spatial correlation Province du Supérieur; Ministère des Ressources naturelles, Québec, Geological Survey, Special Volume 4, Part 1, p.26-57 QUATERNARY interpretation of the Precambrian geology underlying the Hudson Bay Neoarchean magmatism, north of the Uchi-associated magmatic arc of 4 hornblende+biotite tonalite gneiss 1 15 519988 6022428 2848±7 to a set of north-trending mafic dikes that are interpreted to be part of the DV2002-10, p.17. Sage, R.P. 1991. Alkalic rock, carbonatite and kimberlite complexes of and James Bay lowlands based mainly on available re-processed late Neoarchean plutons, but it is dominated by Mesoarchean batholiths. MAP P.3597–Revised Marathon swarm. This consistent spatial association of pipes and dikes Ontario, Superior Province; in Geology of Ontario, Ontario Geological 5 aphyric dacite tuff 1 15 519989 6047178 2726±2 2742, 2752 aeromagnetic data (OGS 1999, 2003; GSC 2003) and limited - However, the Island Lake domain, like the Uchi domain to the south, PLEISTOCENE AND RECENT (and in some cases, local faults) in the lowlands implies that exploration DePaolo, D.J. 1981. Crustal growth and mantle evolution: inferences from Survey, Special Volume 4, Part 1, p.683-709. 6 biotite tonalite 1 15 522267 5986363 2863.3±0.7 drill hole information (McIlraith and Stott 2005). Much of the interpretation contains widespread evidence of Neoarchean magmatism and should focus not just on the major faulted terrane boundaries, such as models of element transport and Nd and Sr isotopes; Geochimica et is anchored by comparing similar aeromagnetic features in the exposed sedimentation. A few remnants of 2.9 to 3.0 Ga supracrustal rocks are UNCONFORMITY 7 conglomerate 1 15 522717 5985941 2863.8±0.7 the North Kenyon fault between the Northern Superior and Sachigo Cosmochimica Acta, v.44, p.1185-1196. Sage, R.P. 2000. Kimberlites of the Attawapiskat area, James Bay PRECAMBRIAN GEOLOGY portions of the Archean Superior Province and the Paleoproterozoic preserved in the NCT, notably in the Red Lake and North Caribou Lake 8 quartz-rich conglomerate 1 15 522788 5985927 2865±1 superterranes, and the Superior Province–Trans-Hudson Orogen Lowlands, northern Ontario; Ontario Geological Survey, Open File Trans-Hudson Orogen in Ontario, Manitoba and Québec. The results greenstone belts. Rift sequences of circa 2.9 Ga age occur locally in the boundary (see Figure 1), but also close to major dike swarms that lie Geological Survey of Canada 2003. Canadian aeromagnetic data base; Report 6019, 341p. PRECAMBRIAN 9 arkose 1 15 523989 6044128 2713±5 provide a general framework of interpreted supracrustal belts, plutonic central NCT containing 2.97 to 3.048 Ga detrital zircons and subsequent within the corridors of Jurassic kimberlite magmatism (Heaman, Regional Section, Geological Survey of Canada, Earth 10 sandstone 1 15 526778 6026659 2722.6±2.7 subdivisions, major faults and Proterozoic mafic dikes. A Miscellaneous marine volcanism. Two periods of plutonic and metamorphic activity HUDSON BAY AND JAMES Kjarsgaard and Creaser 2003) in Ontario and the corridor of Keweenawan Sciences Sector, Natural Resources Canada. Sandford, B.V. and Norris, A.W. 1975. Devonian stratigraphy of the Release–Data (MRD 233) digital publication accompanies maps occur across the NCT at 2.89 to 2.895 Ga and 2.85 to 2.86 Ga. The NCT MESOPROTEROZOIC 11 fragmental felsic volcanic 1 15 527687 6031850 2718.2±1.0 magmatism defined roughly by the northward extension of the Trans- Hudson Platform; Part I: stratigraphy and economic geology; Department P.3597-Revised to P.3599 inclusive. It includes the shapefiles for all 3 forms a Mesoarchean core upon which subsequent Neoarchean crust BAY LOWLANDS REGION 12 hornblende granodiorite 1 15 527589 6050927 2715±8 2747 Superior Tectonic Zone. Halls, H.C., Stott, G.M. and Davis, D.W. 2005. Paleomagnetism, of Energy Mines and Resources Canada, Memoir 379, 124p. maps and a seamless map of the lowlands; sets of seamless regional has been added to the north and south margins and wraps around the 35 Alkalic Intrusive Suite and Carbonatite (circa 1.0 to 1.2 geochronology and geochemistry of several Proterozoic mafic dike 13 quartz+feldspar porphyritic rhyolite 1 15 528034 6030203 2722.5+6.1/-4.4 aeromagnetic and gravity images; Landsat images and digital elevation east side under the James Bay Lowland. Ga): alkalic syenite, ijolite, associated mafic and The aeromagnetic interpretation of mafic dike subswarms, of different swarms in ; Ontario Geological Survey, Open Skulski, T., Corkery, M.T., Stone, D., Whalen, J.B. and Stern, R.A. 2000. INTERPRETED FROM 14 sandstone 1 15 528218 6028675 2709.4±1.7 model (DEM) of the lowlands; tables of geochronology, kimberlite pipes, ultramafic rocks, and carbonatite age and orientation, indicates that block rotation of the Superior Province File Report 6171, 75p. Geological and geochronological investigations in the Stull Lake– quartz porphyry in mafic volcanic 15 2857±2 diamond-drill hole information, and AFRI files. It also includes contoured Island Lake Domain 25b 35a Carbonatite and related rocks 15 1 530988 5978727 may have occurred episodically along major, reactivated Archean breaks Edmund Lake greenstone belt and granitoid rocks of the northwestern 25b estimates of depth to Precambrian basement in shapefile and pdf formats, 1018 m AEROMAGNETIC DATA 16 hornblende granodiorite 1 15 531389 6042727 2710±6 (faults). Dating of minerals along these faults might reveal the most active Halls, H.C., Davis, D.W., Stott, G.M., Ernst, R.E. and Hamilton, M.A. 2008. Superior Province; in Report of Activities 2000, Manitoba Industry, with notes. The following notes are an expansion of Stott and Rainsford The Island Lake domain is largely plutonic with some Mesoarchean to 34 Mafic and Related Intrusive Rocks 17 sandstone 15 periods of rotation, and it is these breaks that could have served as planar The Paleoproterozoic Marathon Large Igneous Province: new Trade and Mines, Manitoba Geological Survey, p.117-128. 1 534147 6030004 2718.7±2 (2006). Neoarchean volcanic belts with geophysical characteristics that show (circa 1.0 to 1.2 Ga) 18 felsic tuff 1 15 534147 6030004 2720.9±0.9 some relationship to the belts within the NCT. The boundaries of the corridors of crustal access for kimberlite pipes. evidence for a 2.1 Ga long-lived mantle plume event along the 34c Ultramafic, gabbroic and granophyric intrusions southern margin of the North American Superior Province; Precambrian Stone, D. 2005. Precambrian geology, northern Superior area; Ontario WEST SHEET 19 biotite tonalite 1 15 560489 6007926 2855±5 2758 Methodology Island Lake domain are probably the least understood and remain the 90°W most contentious; modifications to the boundaries proposed by Parks et Near the southern margin of the James Bay Lowland and between two Research, v.162, p.327-353. Geological Survey, Preliminary Map P.3545, scale 1:250 000. 33 Mafic Intrusive Rocks 20a carbonatite 1 15 563590 6069227 1822±96 al. (2006) and Percival et al. (2006) are made in Figure 1 based partly northeast-trending sinistral faults, a cluster of ultramafic alkalic diatreme 33a Mackenzie mafic dike swarm (1267 Ma) A composite image was used for interpreting the regional geology based 25b,e 21 biotite granodiorite 1 15 569291 6091076 2846±5 2872 2717 on geochronology and isotopic results of Rayner and Stott (2005) near breccia pipes occurs, which was the target of diamond exploration in the Heaman, L.M. and Kjarsgaard, B.A. 2000. Timing of eastern North Stone, D., Corkery, M.T., Hallé, J., Ketchum, J., Lange, M., Skulski, T. Scale 1:500 000 on the shaded relief of both colour total field and greyscale first vertical 22 fragmental felsic volcanic 1 15 572780 6040336 2732.4±1.0 the James Bay Lowland where the Island Lake domain appears to have 1970s (e.g., Reed and Sinclair 1991). These small pipes are recognizable American kimberlite magmatism: continental extension of the Great and Whalen, J. 2004. Geology and tectonostratigraphic assemblages, INTRUSIVE CONTACT derivative of the regional aeromagnetic survey in Ontario (OGS 1999) incorporated some older crustal contaminants in contrast to the more by their strong magnetic response but, although apparently related to the Meteor hotspot track?; Earth and Planetary Science Letters, v.178, eastern Sachigo Subprovince, Ontario and Manitoba; Ontario 10000 m 0 5 10 15 20km 23 biotite tonalite 1 15 573664 6073414 2822.0±0.8 plus the colour shaded relief images of first and second vertical 25b,e juvenile Oxford–Stull domain (Rayner and Stott 2005). Jurassic kimberlite pipes of the Attawapiskat cluster, they are not kimberlitic p.253-268. Geological Survey, Preliminary Map P.3462, scale 1:250 000. 24 biotite granodiorite 1 15 574901 6078016 2722.5±2 derivatives of a high-resolution aeromagnetic supergrid (OGS 2003) or diamondiferous. Southeast of this cluster, the Martison carbonatite is of PALEOPROTEROZOIC 2741 covering a significant part of the James Bay Lowland and straddling a 25 hornblende+biotite tonalite gneiss 1 15 576191 6085526 2814±4 3209, 3572 uncertain age but possibly associated with the Keweenawan magmatism, Heaman, L.M., Kjarsgaard, B.A. and Creaser, R.A. 2003. The timing of Stott, G.M. 2003. Diabase dike swarms as structural controls for kimberlite r Oxford–Stull Domain e NTS References: 43 E,L,M; 44 D; 53 F,G,H,I,J,K,N,O,P; 54 A,B small portion of the Hudson Bay Lowland. After experimenting with iv 27 Carbonatite–Alkalic Intrusive Suite (circa 1.8 to 1.9 Ga) 26 biotite tonalite gneiss 1 15 580041 6101226 3292, 2854 circa 1100 Ma. Its significant phosphate deposit has attracted recent kimberlite magmatism in North America: implications for global pipes under the James Bay and Hudson Bay lowlands, Ontario; 8th R various images of the data sets, this combination provided a reasonable Duc k development interest by PhosCan Chemical Corporation. kimberlite genesis and diamond exploration; Lithos, v.71, p.153-184. International Kimberlite Conference, Extended Abstracts, FLA317, 3p. ©Queen’s Printer for Ontario, 2008. 27 granite dike 1 15 580041 6101226 2690-2711 tool for interpreting the Precambrian substrate under the lowlands and At the northern margin of the Sachigo superterrane, the Oxford–Stull 28 biotite tonalite 1 15 585390 6038676 2733.7±1.7 2849±12 was compared with the first vertical derivative Bouguer gravity map (OGS domain (OSD) stretches from Manitoba to the James Bay Lowland 26 Mafic Intrusive Rocks (see Figure 1). In Manitoba, the OSD has been best studied in the The region bordering the lowlands within the Oxford–Stull domain has the Heaman, L.M., Kjarsgaard, B.A. and Creaser, R.A. 2004. The temporal Stott, G.M. and Corfu, F. 1991. Uchi Subprovince; in Geology of Ontario, This map is published with the permission of the Director, Ontario 29 foliated tonalite 1 15 587062 6081622 2701.1+4.0/-1.8 2745, 2840 1999) in assessing the locations of probable greenstone belts in areas Oxford Lake–Knee Lake area where it includes several assemblages potential for hosting gold deposits comparable to similar Archean greenstone evolution of North American kimberlites; Lithos, v.76, p.377-397. Ontario Geological Survey, Special Volume 4, Part 1, p.145-236. Geological Survey. outside the high-resolution aeromagnetic supergrid. Most of the 25b 26a Sutton Inliers: gabbroic sills of the Molson event 30 hornblende granodiorite 1 15 591879 6044115 2718.7±1.5 (ages are compiled in Manitoba Geological Survey 2005) ranging in age belts elsewhere in the province. Numerous shear zones lie close to and interpretations were done on transparent sheets, which were subsequently parallel to the greenstone belts just west of James Bay Lowland and south Janse, A.J.A., Downie, I.F., Reed, L.E. and Sinclair, I.G.L. 1989. Alkaline Stott, G.M., Corkery, T., Leclair, A., Boily, M. and Percival, J. 2007. A 25b,e (circa 1880 Ma) 31 gabbro 1 15 591290 6075281 2716±1.3 from Mesoarchean (2870 to 2830 Ma) to Neoarchean volcanism at 2722 25b digitized into geographic information system (GIS) format. Aeromagnetic of Hudson Bay Lowland. These shear zones, generally trending east to intrusions in the Hudson Bay Lowlands, Canada: exploration methods, revised terrane map for the Superior Province as interpreted from 12,25b 26b Pickle Crow mafic dike; normally magnetized northwest- 32 intermediate tuff 1 15 591575 6072948 2718.1+2/-1.8 Ma and detrital zircons in overlying sediments as young as 2707 Ma 9 relief was enhanced by shading at 45° inclination from three different southeast, locally splay into the greenstone belts and could be a focus for petrology and geochemistry; in Kimberlites and Related Rocks, v.2, Ross, aeromagnetic data; in Woodruff, L. (ed.), Institute on Lake Superior trending subswarm (Molson swarm) (circa 1876 Ma) 5° 90° 80° 75° (Corkery et al. 2000). Across the breadth of the OSD, there is a Thomps a 85° 33 hornblende granodiorite-monzonite 1 15 595691 6077926 2714±8 2813, 2720 directions (000°, 315° and 045°), which provided improved definition of on Hudson Bay gold exploration in this region. Owing to the relative lack of Archean bedrock J., Jaques, A.C., Ferguson, J., Green, D.H., O’Reilly, S.Y., Danchin, R.V. Geology Proceedings, 53rd Annual Meeting, Lutsen, Minnesota, v.53, 25b,e tob predominance of Neoarchean U/Pb zircon ages derived through sensitive 55 ni 34 quartz+feldspar porphyry 1 15 603214 6041472 2730.4±1.3 2735.6±2.2 various features trending in different directions, especially the mafic dikes, exposure, exploration for gold-bearing targets would require extensive and Janse, A.J.A. (eds.), Geological Society of Australia, Special Publication part 1, p.74-75. 26c Pickle Crow mafic dike; reversely magnetized ° a high-resolution ion microprobe (SHRIMP) analyses of volcanic and M P.3597– faults and lithologic contacts. In the absence of descriptions from any drill surficial till sampling. 14, Blackwell Scientific Publications, p.1193-1203. HUDSON BAY northwest-trending subswarm (Molson swarm) 35 plagioclase porphyry 1 15 613019 6014137 2724.6±1.0 2715.1±1.5 plutonic rocks near the Manitoba–Ontario border (as young as 2710 Ma) Revised core of Precambrian rocks underlying the lowlands, generalized Stott, G.M., Davis, D.W., Parker, J.R., Straub, K.H. and Tomlinson, K.Y. 25b,e (circa 1876 Ma) P.3598– 36 hornblende granodiorite 1 15 613376 6069023 2716.2±1.2 and farther east near the James Bay Lowland in Ontario (2737 to 2696 Ma). 25b,e James interpretations were made of the probable rock types based on comparable Significant mafic to ultramafic intrusions occur close to the western margin Kamo, S.L. 2008. U-Pb ID-TIMS geochronology of late tectonic rocks from 2002. Geology and tectonostratigraphic assemblages, eastern 26d Mafic plutons of uncertain age; gabbro, diorite, quartz Revised Bay 37 felsic tuff 1 15 622884 6060853 2718.1±0.9 aeromagnetic characteristics in the exposed part of the Superior Province Neoarchean to Mesoarchean Nd model ages with negative εNd values 26d diorite are consistent with relatively juvenile crustal growth (Skulski et al. 2000; of the James Bay Lowland in the vicinity of McFaulds Lake. Recent an intrusive complex in the Hudson Bay Lowlands, Ontario; unpublished Wabigoon Subprovince, Ontario; Ontario Geological Survey, outside of the lowlands. 38 rhyodacite tuff 1 15 628783 6059926 2838±1.1 2846.6±1.3 Rayner and Stott 2005). The OSD displays some evidence of discoveries of massive Cu-Ni-PGE mineralization in association with these report for the Ontario Geological Survey, 6p. Preliminary Map P.3449, Geological Survey of Canada Open b INTRUSIVE CONTACT 39 feldspar porphyritic granodiorite 2 16 403925 6104905 2726±6 (max) ca. 2780 -1.69 3.10 Mesoarchean mid-ocean ridge basalt (MORB)-like sequences concurrent intrusions encourages the investigation of other intrusions, some of which File 4285, scale 1:250 000. are newly discovered nearby. Most of these intrusions are poorly exposed Kong, J.M., Boucher, D.R. and Scott-Smith, B.H. 1999. Exploration and 27 3 2710±7(min) with continental magmatic growth within Northern Superior superterrane 3a 25 Trans-Hudson Orogen Supracrustal Rocks P.3599 General Features D b and more are anticipated to be discovered with higher resolution geology of the Attawapiskat kimberlites, James Bay Lowlands, northern Ke Q and NCT margins to the north and south, respectively. The southern u 50 nora 40 quartz-rich grit at Precam.-Paleoz. contact 2 16 403925 6104905 2668 to 2745^ c 25a Mafic and ultramafic metavolcanic rocks, ° u k Wi geophysical data. These intrusions might form a coeval, late-tectonic suite Ontario, Canada; Seventh International Kimberlite Conference, nni é 3 R peg b contact of the OSD with the Island Lake domain of the NCT shows a 3 b a i metasedimentary rocks, differentiated mafic to Dry 41 tonalite-quartz diorite 2 16 440617 5946704 2727±4 Some of the magnetically inferred trend lines are highlighted on the map v de e 0.83 2.84 that extends from Big Trout Lake along the southern margin of the Oxford– Extended Abstracts, Cape Town, South Africa, p.446-448. e n prevalence of Mesoarchean zircon ages and isotopic evidence for a r c b (shown as the “Inferred foliation and/or bedding trend” line style) to ultramafic intrusions of the Fox belt 42 granodiorite 2 16 475190 5945618 2696±3 2886±12 0.03 2.91 shared constructive history with the OSD across the Stull–Wunnummin Stull domain to Highbank Lake on the edge of the James Bay Lowland 26d illustrate the overall pattern of trends corresponding to planar lithologic 25b Undifferentiated clastic and carbonate metasedimentary Timmins b and wrapping around a large granitic intrusion west of McFaulds Lake. LeCheminant, A.N. and Heaman, L.M. 1989. Mackenzie igneous events, Th 43 tonalite gneiss 2 16 484785 5961820 2683±5 2729±5 0.89 2.78 fault. rocks under b contrasts, bedding or contacts. Generally, west- and northwest-trending Similar, coeval intrusions might also occur near the North Kenyon fault. Canada: Middle Proterozoic hotspot magmatism associated with ocean Bay 44 tonalite to granodiorite gneiss 2 16 485636 5964254 2813±4 ca. 2740 1.70 2.86 U.S.A Lake faults show evidence of dextral transcurrent displacement and northeast- At this stage, one could speculate that these intrusions form a magmatic opening; Earth and Planetary Science Letters, v.96, p.38-48. 25b,e 25c Sutton Inliers - Sutton Ridges Formation: unsubdivided Superior b At the edge of the James Bay Lowland in Ontario, the OSD includes a 45 biotite tonalite gneiss 2 16 492417 5945180 2700±4 0.91 2.83 trending faults show sinistral displacement. Sites where radiometric ages clastic metasedimentary rocks (including wacke, Sudbury calc-alkalic metavolcanic sequence containing volcanic-hosted massive suite, derived from the mantle and intruded during the late stage of terrane 25b b of rock units were obtained are numbered on the map face and siltstone, argillite and conglomerate), and iron formation Sault awa 46 biotite tonalite to granodiorite 2 16 498283 5963777 2715±5 sulphide deposits at McFaulds Lake (Map No. 47), with a U/Pb zircon collision along the boundaries of the Oxford–Stull domain as well as Manitoba Geological Survey 2005. Manitoba geochronology database; Ott summarized in Table 1. Kimberlite pipes are shown and numbered, 26d 25d Sutton Inliers - Nowashe Formation: carbonate Ste. Marie 47b intermediate volcanic (McFaulds Lake) 2 16 563126 5850462 2737±7 1.13 2.84 SHRIMP age of 2737±7 Ma (Rayner and Stott 2005). This is comparable bordering, possibly coeval, late-tectonic felsic plutons, such as the large Manitoba Industry, Economic Development and Mines, Manitoba 45° Lake corresponding to the list in Table 2. Most of the lowlands are underlain by 26d 26d metasedimentary rocks (dolomite, cherty dolomite, Huron b in age to the Confederation assemblage in the Uchi domain. In this intrusive complex west of McFaulds Lake. Geological Survey, Open File Report 2005-3, digital Web release. 25b 48 hornblende-biotite quartz diorite to diorite 2 16 593549 5824221 2724.3±0.8 Archean rocks but a broad area across the northern half of the Hudson stromatolitic dolomite, argillaceous dolomite) b respect, it is noteworthy that the aeromagnetic evidence shows a Location Map 1 cm equals 200 km 49 quartz diorite 2 16 605500 5832171 2728±5 1.44 2.80 Bay Lowland lies within the Trans-Hudson Orogen (THO). Part of this 25e Undifferentiated clastic metasedimentary migmatite discontinuous chain of greenstone belts, extending from the Uchi domain, Within the Paleoproterozoic Trans-Hudson Orogen that underlies the McIlraith, S.J. and Stott, G.M. 2005. Lowland drill hole data compilation; 12,11 50b quartz diorite 16 2710±4 area is interpreted as Archean granitoid rock overprinted by the THO. 26d 2 621021 5864670 2.44 2.71 wrapping around and joining the OSD, east of the McFaulds Lake northern half of Hudson Bay Lowland, the Sutton Inliers are suspected to Ontario Geological Survey, Miscellaneous Release—Data 152. 25b,e b Much of the THO is represented by a broad, folded metasedimentary INTRUSIVE CONTACT 51 quartz-rich grit at Precam.-Paleoz. contact 2 17 306189 5854792 2664 to 2770^ belt (Stott and Rainsford 2006). Overall, both the Meso- and Neoarchean be similar in lithologies and age, circa 1960 Ma, to the Povungnituk Group 56°N basin, incorporating iron formation, most notably in the exposed Sutton 25b,e 52c MacFayden 1 kimberlite 17 177.2±1.3 supracrustal belts of the OSD appear to be dominated by juvenile, oceanic in the Cape Smith belt of northern Québec, the Nastapoka Group on the edge Ontario Geological Survey 1999. Single master gravity and aeromagnetic 91°W 3 301516 5862943 Inliers and their folded continuity northwards under the Paleozoic rocks 25a,b 33a 23 Mafic Dikes c crust formed without significant input from adjacent older terranes except of Hudson Bay in western Québec, and the Flaherty Formation in the Belcher data for Ontario; Ontario Geological Survey, Geophysical Data Set Donovan Fort Severn 89 SYMBOLS 53 Charlie (C1) kimberlite 3 17 302167 5861400 179.9±1.6 toward Hudson Bay. Group on the Belcher Islands in Hudson Bay. The well-preserved gabbroic 1036. Lake 26d 26d d close to the North Kenyon fault and the Northern Superior superterrane. ! 54 Uniform (U1) kimberlite 4 17 303979 5863163 180 sills that cap the shallow-water quartzite, iron formation and dolomite beds 15,12 Fort Severn f These maps display a composite of the bedrock geology of the northern 23a Marathon mafic dike; north-northwest- to north- Geologic contact, Terrane boundary 55 Golf (G1) kimberlite 5 17 309956 5866796 156±2 have received some attention for potential Ni-Cu-PGE mineralization. Ontario Geological Survey 2003. Ontario airborne geophysical surveys, 3 Uchi Domain 3 interpreted f portion of the Archean56°N Superior Province in Ontario. The regional terranes magnetic data, grid data, magnetic supergrids; Ontario Geological a 25b northeast-trending subswarm (circa 2101 to 2110 Ma) 56 Alpha-1North kimberlite 5 17 312386 5842382 156±2 25a,b (trend only) and domains are shown in Figure 1, based on Stott et al. (2007). Some In the southwestern corner of the James Bay Lowland, a set of gabbro- Survey, Geophysical Data Set 1037. 57c 17 179.4±2.2 The Uchi domain forms the southern part of the North Caribou terrane 15,12 Provincial park Bravo "A" kimberlite 3 305529 5857130 interpreted features to note: syenite intrusions forms an arcuate chain that extends southward beyond 56°N 26d 23b Marathon, Kapuskasing or Biscotasing mafic dike; c where magmatic U/Pb zircon ages and Nd model ages indicate the 25a,b Area of inferred 58 Bravo "B" kimberlite 3 17 305529 5857130 175.7±1.8 the lowland cover. These intrusions resemble the ca. 1100 Ma Coldwell Ontario Geological Survey 2006. 1:250 000 scale bedrock geology of northeast-trending subswarm (circa 2124 or 2170 Ma) widespread presence of 2.8 to 2.9 Ga crust, comparable to the Island Trans-Hudson 59c Kyle 1 kimberlite 4 16 608467 5813846 1123±20 • The merging of greenstone belts of Uchi domain and Oxford–Stull Complex, on the north side of Lake Superior, in lithology and magnetic Ontario; Ontario Geological Survey, Miscellaneous Release—Data Hosea domain under the James Bay Lowland; Lake domain forming the north flank of the NCT. The Uchi domain 11,12 Lake 26d 23c Biscotasing mafic dike; north-northeast-trending Orogen overprint on First Nation reserve 60c Kyle 5 alnoite 4 16 5882214 1076.2±3.8 intensity, and could draw attention to their PGE potential. The 126-Revised. 15,12 616617 includes circa 2887 Ma Pembina tonalite on Lake St. Joseph and 2860 r Archean crust • A large indentor-like feature underlies the James Bay Lowland, flanked 15,12 e subswarm (circa 2175 Ma) b southernmost intrusions of this arcuate chain are the most accessible for iv 61 granodiorite gneiss 2 16 609277 5787608 2690±3 2787±6, -0.34 2.95 Ma Pickle Crow porphyry (Corfu and Stott 1993) in addition to pre-2.8 Ga R by faults (see Map P.3599); rn exploration since Paleozoic cover rocks significantly increase in thickness Osmani, I.A. 1991. Proterozoic mafic dike swarms in the Superior e !! v volcanic assemblages. The Uchi domain was constructed largely by 25b e Approximate area Township ca.2900 • The separation of English River and Quetico metasedimentary domains northward over the northern intrusions of this suite. Province of Ontario; in Geology of Ontario, Ontario Geological Survey, S !!! autochthonous, episodic additions of volcanic assemblages and 17 !!!! of “Sutton Inliers”, 3 Mafic Dikes !!! 62 K-feldspar megacrystic granodiorite 6 16 372388 6072085 >2705±2 -1.11 2.95 south of the James Bay Lowland by a ridge of felsic plutonic rocks, Special Volume 4, Part 1, p.661-681. 3 12,11 a 15,12 3 ! !! accompanying plutons during the Neoarchean era (Stott and Corfu 1991). 3 17a Matachewan mafic dike; northwest-trending swarm with outcrops or -1.06 3.02 with high magnetic field intensity, extending westward from the Opatica Acknowledgements a ! 63 quartz diorite 6 16 373801 6065609 2709.1±0.8 Neoarchean assemblages, forming the core of the Uchi domain, appear 11,12 thin Paleozoic cover Road, trail, gneisses of Québec. The Opatica terrane might extend to the Marmion Parks, J., Lin, S., Davis, D. and Corkery, T. 2006. New high-precision 11,12 (circa 2454 Ma) 64e alkalic ultrabasic diatreme breccias 7 17 306976 5573404 152±8 to have built upon or lie adjacent to the NCT Mesoarchean crust. The 12,11 railroad terrane where the latter is interpreted to underlie most of the eastern D.R.B. Rainsford of the Ontario Geological Survey provided helpful insight U-Pb ages for the Island Lake greenstone belt, northwestern Superior e eastern extent of the Uchi domain underlies the James Bay Lowland Iron formation 65 alkalic ultrabasic diatreme breccias 7 17 336646 5574811 180±9 Wabigoon Subprovince; and support with the aeromagnetic data. The revised and re-processed Province: implications for regional stratigraphy and the extent of the INTRUSIVE CONTACT where, from high-resolution aeromagnetic images, it appears to merge Powerline 66c alkalic ultrabasic diatreme breccias 8 17 439311 5574837 235.6±2.2 • The Trans-Hudson Orogen, including areas of reworked Archean crust, aeromagnetic dataset and derived products were provided by the North Caribou terrane; Canadian Journal of Earth Sciences, v.43, with the OSD. The resulting merged greenstone–granite domain continues 25b 2 12,11 67 Goldray carbonatite 9 17 493247 5586109 1884±2 appears to underlie the northern half of the Hudson Bay Lowland, Geological Survey of Canada through W. Myles (A/Section Head, p.789-803. Husky WIN 6 eastward under the James Bay Lowland on strike with the Eastmain ISK 0 25b c 26d 15,12 ARCHEAN Fault, interpreted; g based on interpretation of aeromagnetic maps; Radiation Geophysics). S. Josey provided digital cartographic support, Lake 12,11 68 Argor carbonatite 9 17 525869 5629661 1950 greenstone–granite domain of Québec. 0 dextral horizontal Town • Apparent reworked Archean Northern Superior superterrane crust under updated and rectified the diamond-drill hole database compilation, and Percival, J.A., Sanborn-Barrie, M., Skulski, T., Stott, G.M., 16 Pyroxenite, Diorite, Monzonite, Syenite displacement ! Notes and Abbreviations the Hudson Bay Lowland within the Trans-Hudson Orogen; assembled the final tables and base map. Several exploration companies Helmstaedt, H. and White, D.J. 2006. Tectonic evolution of 0 15,12 Proterozoic Mafic Dikes 3 • Broad areas of pronounced aeromagnetic field intensity characterize are thanked for their assistance in obtaining rock samples from the the western Superior Province from NATMAP and 3 a 3 15,12 3 Fault, interpreted; Location of Methods large parts of the Northern Superior superterrane under the Hudson Sachigo Subprovince and Hudson Bay Lowland, in particular, De Beers Lithoprobe studies; Canadian Journal of Earth Sciences, 15,12 a 15 15,12 Massive to Foliated Granodiorite to Granite sinistral horizontal ! 1 geochronology All U-Pb zircon thermal ionization mass spectrometry (TIMS) except: Bay Lowland in Ontario and lie on strike with the Pikwitonei gneisses, Several mafic dike swarms have been identified across Ontario Canada Exploration Inc., Wallbridge Mining Co. Ltd. and Spider Resources v.43, p.1085-1117. 15,12 1 a (e.g., Osmani 1991; Buchan and Ernst 2004) and some of these extend 15,12 displacement sample K-Ar biotite including the Assean and Split Lake blocks, in Manitoba; Inc. 15,12 b U-Pb zircon sensitive high-resolution ion microprobe (SHRIMP) • Potential correlation of Northern Superior superterrane with the 3.8 Ga into the lowlands region. The most prominent, especially in the James 14 (keyed to Table 1) 2 Diorite, Quartz Diorite: minor tonalite, monzonite, c Bay region, is the northwestward-radiating Matachewan dike swarm. 3 6 Fault, interpreted; U-Pb perovskite Porpoise Cove volcanics (David et al. 2002) in Tikkerutuk domain and 3 15,12 c References 15,12 a 12,11 granodiorite, syenite and hypabyssal equivalents d U-Pb perovskite (SHRIMP) the >3.5 Ga Assean gneisses (Böhm et al. 2000); Many of these, circa 2450 Ma, dikes are grouped into several “bundles” 15,12 unknown horizontal Location of kimberlite e displacement ! 1 pipe K-Ar phlogopite • Areas interpreted to be part of the Paleoproterozoic Sutton Inlier are of more closely spaced dikes, including one bundle that passes through Böhm, C.O., Heaman, L.M., Creaser, R.A. and Corkery, M.T. 2000. 13 f 15,12 Muscovite-Biotite and Cordierite-Biotite Granite, (keyed to Table 2) Rb-Sr phlogopite outlined where exposed. The Sutton “Inlier”, of shallow-water platform the Attawapiskat cluster of kimberlite pipes. Most of the Attawapiskat Discovery of pre-3.5 Ga exotic crust at the northwestern Superior 15,12 g Granodiorite to Tonalite Inferred foliation Pb-Pb sedimentary units and overlying gabbro sill, does not appear to be one kimberlites are aligned parallel to and alongside one of the Matachewan Province margin, Manitoba; Geology, v.28, p.75-78. 12,11 ^ Range of detrital zircon ages large area but a set of inliers and should in future be referred to as the dikes (see Figure 2), indicating that these Jurassic pipes took advantage 25b,15,12 12 and/or bedding trend Location of alkalic 15,12 12,11 Tonalite to Granodiorite: foliated to massive ! ultramafic diatreme Sutton Inliers. The eastern Sutton Inliers with subsurface extensions of this Paleoproterozoic vertical dike sheet, close to the Winisk fault, to Böhm, C.O., Heaman, L.M., Stern, R.A., Corkery, M.T. and Creaser, R.A. 15,12 inject through the crust from the lithospheric mantle (Stott 2003). It should 5 12,11 12a Biotite tonalite to granodiorite Lowlands boundary breccia pipe References are shallowly dipping, northward concave and crescent-shaped, 2003. Nature of Assean Lake ancient crust, Manitoba: a combined 3 3a 15,12 12b Hornblende tonalite to granodiorite also be noted that a few of the Matachewan dikes cross the Winisk fault c 5 1. Stone 2005 (and references therein). Note that originally published UTM coordinates, which were in NAD 27, have been converted here to NAD 83 values. based on aeromagnetic patterns, which correspond closely with the 3 SHRIMP-ID-TIMS U-Pb geochronology and Sm-Nd isotope study; 2 5 F A 2 Depth to Precambrian 2. Rayner and Stott 2005. distribution of outcrops observed by Bostock (1971). They resemble without aeromagnetic evidence of lateral offset, indicating that the principal U 33 6 11 25 m 25 m Precambrian Research, v.126, p.55-94. 5 3 LT a c Tonalite to Granodiorite: foliated to gneissic with minor # " dextral movement on the Winisk fault pre-dated the circa 2450 Ma 3a Granulite facies bedrock (from diamond- 3. Heaman and Kjarsgaard 2000. “klippe”, in their shape and shallowly northward dip, and might have 15,12 12,11 15,12 supracrustal inclusions metamorphism  drill holes, from seismic 4. Heaman, Kjarsgaard and Creaser 2004. been transported a short distance southwards. Folded strata related Matachewan dikes and was therefore likely late Archean in age. Another Bostock, H.H. 1971. Geological notes on Aquatuk River map-area, 12,11 15,12 0 m 15,12 11,12 data, from outcrop)a 5. Kong, Boucher and Scott-Smith 1999. to the Sutton Inliers are shown aeromagnetically to extend prominent dike swarm, the Marathon dikes, appears to have two trends 3 10 Ontario with emphasis on the Precambrian rocks; Geological Survey 11,12 3a Gabbro, Anorthosite, Ultramafic Rocks 6. Kamo 2008. discontinuously northwards towards the Hudson Bay coast upon south and southwest of the James Bay Lowland (Halls, Stott and Davis of Canada, Paper 70-42, 57p. a Stu See Miscellaneous Release–Data 233 (MRD 233) for more specific 2005; Halls et al. 2008), corresponding to two separate episodes of rgeo 11,12 12,11 7. Janse et al. 1989. apparently reworked Archean crust within the Trans-Hudson Orogen. n R 5 92°W ive INTRUSIVE CONTACT details. 8. Heaman, unpublished 1997 (in Sage 2000). intrusion; the north-trending dikes are circa 2101 to 2110 Ma in age and Buchan, K.L. and Ernst, R.E. 2004. Diabase dike swarms and related r 12,11 15,12 11,12 9. Kwon, unpublished 1986 (in Sage 1991). one of the northeast-trending dikes is dated at about 2126 Ma. Similar 3 9 Hudson Bay Lowland units in Canada and adjacent regions; Geological Survey of Canada, 15,12 15,12 5 12,11 3a Coarse Clastic Metasedimentary Rocks: with minor, north-trending dikes under the James Bay Lowland, inferred to be related 3 r (See “References” section of Marginal Notes.) Map 2022A, scale 1:5 000 000, with accompanying notes. 12,15 3a e 11,12 iv mainly alkalic, mafic to felsic metavolcanic rocks to the Marathon swarm, appear to have a close spatial association to the 12,15 5 R 0 n Northern Superior Superterrane 5 12,11 r 12,11 9a Metasedimentary rocks (conglomerate, arkose, arenite, Kyle Lake kimberlite pipes of circa 1100 Ma (Keweenawan) age, implying e v Buchan, K.L., Harris, B.A., Ernst, R.E. and Hanes, J.A. 2003. Ar-Ar dating 11,12 15,12 e wacke, sandstone, siltstone, argillite) a role played by these dikes in controlling the emplacement of kimberlites 12,15 S 5 5 33 12,11 Table 2. Kimberlite pipes in the Hudson Bay and James Bay lowlands. The Northern Superior superterrane (see Figure 1) forms a 1000 km long of the Pickle Crow diabase dike in the western Superior craton of the 15,12 12,15 a SOURCES OF INFORMATION similar to the Matachewan dikes. Other dike swarms that transect the 11,12 8 band of distinctively strong magnetic intensity. Under the Hudson Bay of Ontario and implications for a possible plume centre 3 Migmatized Supracrustal Rocks: metavolcanic and Map No. Name Age (Ma) Map No. Name Age (Ma) Archean crust, under the Paleozoic cover rocks of the lowlands, include 12,15 12,15 3a Lowland in Ontario, broad areas of strong aeromagnetic intensity are associated with ca. 1880 Ma Molson magmatism of Manitoba; in Annual 33 minor metasedimentary rocks, mafic gneisses of Digital base map information derived from the Ontario Land Information 1 K1 - Kyle 1123 ± 20 16 Bravo-B1 175.7 ± 1.8 the northwest-trending Mackenzie dikes (1267 Ma, LeCheminant and a interpreted as late tectonic granodioritic batholiths similar to those that Meeting of the Geological Association of Canada, Mineralogical 3 5 uncertain protolith Warehouse, Land Information Ontario, Ontario Ministry of Natural Heaman 1989) and the north-northeast-trending and north-northwest- 3 15,12 15,12 2 K2 - Kyle 17 Victor-1 Association of Canada, Society of Economic Geologists, Vancouver, a 15,12 dominate the magmatic arc just north of the Uchi domain (see Figure 1) 5 15,12 Resources, scale 1:20 000, and from 1:50 000 scale maps of the trending Molson dikes. The latter set of Molson dikes, the Pickle Crow Canada (published as CD and printed volume), p.17. 12,15 7 3 K3 - Kyle 18 Whisky but overprinted by late Archean dextral shearing related to the Winisk 3 11,12 15,12 5 Metasedimentary Rocks: wacke, siltstone, arkose, National Topographic System (NTS), with modifications by staff of the subswarm, based on on-strike extension and parallel-strike to the Pickle 3a 11,12 fault. This superterrane contains U/Pb zircon ages of 3.2 to 3.1 Ga for c argillite, slate Ministry of Northern Development and Mines. 4 K4 - Kyle 19 AT 56 3 15,12 12,11 12,11 Crow dike of 1876 +/- 8 Ma Ar-Ar age (Buchan et al. 2003), appears to 2 12,11 15 Corfu, F. and Stott, G.M. 1993. U-Pb geochronology of the central Uchi 3 15 5 3 felsic plutonic rocks in the Assean Lake block in Manitoba, and detrital 3 3a 33 7a Wacke, siltstone, argillite 5 K5 - Kyle 1076.2 ± 3.8 20 X-Ray trend across a north-northeast-trending set of dikes near the Manitoba Subprovince, Superior Province; Canadian Journal of Earth Sciences, a 0 12,11 a zircons in metasedimentary rocks up to 3.9 Ga in age (Böhm et al. 2000; 3 15,12 7c Marble, chert, iron formation, minor metavolcanic rocks The geological data is, in part, from OGS 2006, Stone 2005 and Stone border. This north-northeast-trending set of dikes are assigned to the 12,15 3a 12,11 6 Golf-G1 156 ± 2 21 Delta-D1 v.30, p.1179-1196. 3 F Böhm et al. 2003). Neodymium model ages (DePaolo 1981) range from 3 12,11 12,11 11,12 aw 7e Paragneiss and migmatites et al. 2004. (See “References” section of Marginal Notes.) Biscotasing dike swarm, circa 2175 Ma, based on an unpublished a 15,12 5 n R 3 12,15 3 iv 7 Uniform-1 180 22 Yankee-1 circa 3.5 to 4.2 with εNd values to -10.5 at 2.7 Ga or older. Mesoarchean 15,12 3 3 e a a r baddeleyite age from a dike near North Spirit Lake, south of Map P.3597– 12,15 3 15,12 6 3 12,11 8 Good Friday 23 Zulu-1 (2.846 and 2.814 Ga) and Neoarchean plutonic rocks occur in the limited a Felsic to Intermediate Metavolcanic Rocks: rhyolitic, The aeromagnetic base underlying the geological interpretation on this Revised (M.A. Hamilton, Jack Satterly Geochronology Laboratory, 12,15 12,11 12,11 12,11 ver 12,15 Ri 5 12,11 exposure of the Northern Superior superterrane in Ontario with an inherited rn 5 15,12 rhyodacitic, dacitic and andesitic flows, tuffs and map is a greyscale shaded relief image of the first vertical derivative of 9 MacFayden-1 177.2 ± 1.3 24 X-Ray-1 University of Toronto, personal communication, 2008). 12,11 ve c 33a Se 5 age of 3.572 Ga and pre-3.0 Ga Nd model ages (Skulski et al. 2000). 3 12,11 breccias, and related migmatites the regional aeromagnetic survey (OGS 1999; GSC 2003), and a first 2 10 Unnamed 25 Delta-North 33 a 39, 5 vertical derivative of a high-resolution aeromagnetic supergrid (OGS Phanerozoic Intrusions 15,12 5 11 MacFayden-2 26 Alpha-1N 156 ± 2 Trans-Hudson Orogen 12,15 40 Mafic to Intermediate Metavolcanic Rocks: basaltic and 2003), both with illumination direction from 000° and declination 045°. 12,11 1 12,11 15,12 12 Unnamed 27 Alpha-1 3 251 m 5 andesitic flows, tuffs and breccias Apart from the Attawapiskat kimberlite pipe cluster described below under 3 5 33 5 5 A marked magnetic discontinuity can be traced eastward roughly midway 15,12 12,15 a a 5 13 Tango-1 28 India-1 “Economic Considerations”, two clusters of mafic to ultramafic pipes and 55°N 4 under the Hudson Bay Lowland between a region of high magnetic relief 12,11 5 Mafic to Ultramafic Metavolcanic Rocks: basaltic and 14 Tango Extension 29 T1 Kimberlite diatreme heterolithic breccias occur near the southern margin of the James 12,11 12,11 1 and complexity that characterizes the Northern Superior superterrane to 3 3 minor komatiitic flows, metasedimentary and pyroclastic rocks Bay Lowland and are described by Sage (2000). The western cluster 3a 12,15 3 3 15 Charlie-C1 179.9 ± 1.6 30 U2 Kimberlite a 3a 15,12 the south and a region of relatively flat magnetic character that more (Figure 2.1 of Sage, 2000), north of Hearst, occurs just northeast of the 12,11 31 U1 Kimberlite 15,12 1 12,15 CREDITS closely resembles the magnetic signature of the Trans-Hudson Orogen. Martison carbonatite and lies mainly between two parallel, northeast- 11 15,12 12,11 15,12 Sac 15,12 a However, a significant portion of the interpreted Trans-Hudson Orogen higo Rock codes generally conform to Provincially Significant Mineral (See Table 1 for age determination methods and references.) trending faults. Two potassium-argon ages on phlogopite from alnoite Ri resembles, from55°N the aeromagnetic image, an extension of the Northern 26,27 12,15 ver 15 Potential (PSMP) map codes (OGS 2006), with modifications. Number Geological interpretation by G.M. Stott, 2007-2008. c 12a c pipes in this cluster give 152 +/- 8 Ma and 180 +/- 9 Ma, which compare 7 3 3 15,12 3 2 2 15,12 3 codes subdivided into a, b, c, etc., are generally arranged from younger Superior superterrane and is interpreted as an area of Archean crust that with the age range of Attawapiskat kimberlite pipes (Janse et al. 1989, a 12,11 15 was overprinted by the Trans-Hudson Orogen. 55°N 14 12,15 12,11 1 to older. Preparation of base map, tables and digital by S. Josey. as reported by Sage 2000). The second cluster of diatreme breccias and 15,12 15,12 12,11 15 12,11 c 12,11 33 b 3 a Some mafic dike swarms are tentatively subdivided into subswarms Informal division between Hudson Bay and James Bay lowlands. alkalic ultramafic dikes occurs near Coral (Sextant) Rapids, on and west 2 3 15 12a 21 3a Cartographic production by A. Evers. The Sutton Inliers have been reinterpreted by comparing the aeromagnetic of Abitibi River (Figure 2.2 of Sage, 2000). There may be a broad array of 14 14 15,12 based on trend and inferred age corresponding to dike trends and 15,12 12,15 3 5 15,12 data and the outcrops mapped by Bostock (1971). Previous regional geology 15 3a 3 15,12 Phanerozoic ages for intrusions in this cluster. Sage (2000) reports that 15 3a ages elsewhere in the exposed part of northern Ontario. maps of Ontario portrayed the Sutton Inlier as a single large mass. This new 7 14 12,11 33 15 15,12 To enable the rapid dissemination of information, this map has not one of the ultramafic diatreme pipes was dated (U/Pb on perovskite) 11 12a 11 15,12 a 0 c This legend is common to all three maps in this set. Not all rock codes interpretation recognizes a set of ridges forming several crescent-shaped 12a 15 received a technical edit. Discrepancies may occur for which the Ontario at 235.6 +/- 2.2 Ma, Triassic age, by L.M. Heaman (University of Alberta, 12b 15 15 or symbols appear on all maps. inliers that dip shallowly northward. They appear to be discontinuously 25 12,11 Ministry of Northern Development and Mines does not assume liability. unpublished data, 1997). A potassium-argon Cretaceous age on a 12b 12a 12 11 12a 11 r related to similar but steeply dipping, folded, shallow-water sedimentary strata, 15 14 15 ive Users should verify critical information. lamprophyric dike of 128 +/- 18 Ma was obtained by Sandford and Norris 15 5 11 11 R 11 29 11 n including linear magnetic anomalies that probably define iron formation, within 15,12 12,11 0 w (1975). 15 33 15 a 3 11 12a a F Issued 2008. the Trans-Hudson Orogen under the Paleozoic rocks closer to the Hudson Bay 3 14 12,11 15 a 5 24 10 12b 11 3 coast. 12a 11 15,12 15 33 3 15,12 12a 12,11 a 1 Economic Considerations 3 15 12a 12,11 3 Information from this publication may be quoted if credit is given. It is 12a 12a 11,12 a 12,11 3 10 62 3 14 11 33 5 recommended that reference to this map be made in the following form: James Bay Lowland 12b a 12b 12a a Since the Hudson Bay and James Bay lowlands are covered by Paleozoic 31 15 15 UTM Zone 15 UTM Zone 16 UTM Zone 17 c 5 15,12 12a 3 Babey 5 15 15 33 14 and locally Mesozoic rocks, an interpretation of the underlying Precambrian, 93°W 2 32 a Stott, G.M. 2008. Precambrian geology of the Hudson Bay and James High-resolution aeromagnetic data (OGS 2003) and limited diamond-drill c Lake 12a 1 11,12 5 mostly Archean, crustal structures has been greatly hampered in the past. 3 2 A 23 5 6 15 11 WINISK 2 6 12b 54B Bay lowlands region interpreted from aeromagnetic data – west hole logs (e.g., McIlraith and Stott 2005) permit a clearer interpretation b B 20 27 12b 63 54A 44D This set of maps illustrates some interesting features that are relevant to 15 15 14 36 12a 5 IO 5 0 12,11 RIVER sheet; Ontario Geological Survey, Preliminary Map P.3597–Revised, of the distribution of Archean supracrustal belts and granitic batholiths ITO 12a 12a 15 the economic characteristics of this region. The Precambrian geology of R 15 53N scale 1:500 000. under the Paleozoic cover of the James Bay Lowland. Perhaps the most 12a N A 12a 12b 15 11 11,12 PROVINCIAL 53P the lowlands region is composed of the Paleoproterozoic Trans-Hudson 12a A T 0 12b 15 15 12,11 5 5 53O 43M 43N 43O striking and significant feature is the aeromagnetic expression of Uchi M N 11 15 15 3 5 3 15 PARK Orogen, occupying the northern half of the Hudson Bay Lowland, and the O 5 a 15 domain greenstone belts, along the southern flank of the Sachigo 12b 15 53K Kenoran Orogen, which dominates the rest of the region. Notably 15 12b 15 11 53J 53I see 5,8 43L 43K 43J superterrane, trending northeast ( Figure 1) under the James Bay overprinting the crustal units of these areas are major faults and 5 37 12 10 14 2 12,11 Lowland and wrapping around the eastern end of the Island Lake domain, 12b 12a 15 5 6 14 14 Proterozoic mafic (diabase) dikes. 12b 11 b 11,12 12a 15 9a 9a 14 11 53F a portion of the Sachigo superterrane. This greenstone trend merges with 5 38 10 5 53G 53H 43E 43F 43G 43H 3 12a 12b 12a 15 6 5 12,11 the Oxford–Stull domain near the western margin of the James Bay 9a 3a 11 33 15,12 5 11 15 11 a 3 5,8 Lowland just east of the McFaulds Lake massive sulphide deposits, Ney 12a 5 15 3a 50° 43D 12b c 43C 43B 43A 3 15 5 10 12 14 145 m currently under exploration by Spider Resources Inc. This combined 2 5 12 Lake 12b 12,11 138 m 147 m array of Neoarchean greenstone belts continues east, narrowing under 12b 15 12b 12 14 14 14 12b 12a 15,12 32M 3 12b 11 42M 42N 42O 42P the James Bay Lowland, towards the Eastmain greenstone–granite 12a 3 12b 6 5 a 2 c 12 15 3 9a 5 6 3 11 N 126 m b 2 12b O 14 domain in Québec. 9a 12a RT 1 0 142 m 12a 9a 12b 11 H 15 42I 32L 9a 15 KE 14 42L 42K 42J 5 12b NYO 12,11 A northern greenstone limb of the merged Oxford–Stull and Uchi domains 9 5 33 N 12,11 116 m 10 9 6 16 Rorke 5 a 30 3 F 5 32E (see Figure 1), near the boundary with the Northern Superior superterrane, 3 14 AU 3 a 5 Lake Echoing 9 15 LT 15 15 3a 154 m 5 14 6 5 11 5,8 42E 42F 42G 42H appears to be dextrally offset by the Winisk fault, but on strike towards 22 14 14 3 er 6 Lake 15 3a rn Riv 90° 14 6 12b 12a 15 Seve 84° the northern Eastmain greenstone–granite domain in Québec. 12b 5 34 5 14 12a 5 12a 3 15,12 9a 15 3 Index to location of UTM zones and 1:250 000 scale NTS sheets. 12b a Some Features of Terranes and Domains 12a 28 12b 12a 15 9a 7 15 6 5 12a 5 12a 12 3 3 15 3 6 9a 12a 9a 3 15 15 12,11 a Tectonically significant subdivisions in the northern Superior Province 12a a 11 17,18 5 0 across Ontario have been progressively defined from field work, limited 3 12,11 6 5 9a 3 3 9a 13 a 3a 9a 3 12a 12,11 geochronology, isotopic studies and aeromagnetic interpretations 6 9a 3a 11 14 c 12a 79 m 9a 3 (e.g., Percival et al. 2006). The terrane and domain boundaries shown in 9a 2 11 2 15 3 6 Winisk I.R. 5 3 b 3 12a c 2 15 a 3 5 9a 6 12a a 12,11 3 Figure 1 incorporate and revise previous interpretations (e.g., Thurston, 3 6 10 3 12 6 2 b 15 11 15 a 11 5 10 6 15 15 15 15 15 Osmani and Stone 1991; Stone 2005; Parks et al. 2006; Percival et al. 12a 12b 12,11 4 11 10 5 2006; Stott et al. 2007). As in the southern Superior Province, terrane- 15 c 3 c 2 c 3 3 2 scale subdivisions, containing supracrustal and plutonic complexes 3 Stull 9a 3 15 12a 2 5 a 12a 5 13 11 3 15 Lake 15 11 3a 3 3 hundreds of kilometres long, are distinguished by lithology, age, isotopic 15 12a 3 15 3 0 a a 12a 11 12a 12a 5 5 33 character, geochemistry and bounding faults. Two sialic terranes, the 5 6 5 a c 12,11 3 12,11 12b 3 3 12b 10 a Northern Superior superterrane and the Sachigo superterrane, each have 15 2 9a 10 9a 6 c 11 15 3 15 complex, but distinct, episodic magmatic and tectonic histories. The 11 12a 2 5 c 10 3 15 9a 15 33 3 3 35 er a 2 9a a 6 v Northern Superior superterrane contains remnants of a magmatic record 2 Ri 5 12a 6 n 12 12a b w from Paleo- to Neoarchean and geophysically and isotopically can be c 12b 15 11 a 12,11 3 15 F 15 2 2 9a 3 15 6 3 12a 5 linked to the Assean gneisses in Manitoba (Böhm et al. 2000) and the b 5 a 12b 12a 2 A 19 6 SEVERN 5 c s 12a 12a b 14 15 Tikkerutuk terrane (Alain Leclair, Geoscientist, Géologie Québec, 12a 15 3 11 h 12a 6 2 11 12,11 e 12b 5 w c 9a 40 to 48 m Figure 1. Regional tectonic subdivisions of northern Ontario (after Stott et al. 2007). personal communication, 2006), which encompasses the 3.8 Ga Porpoise 11 12,11 12,11 e 3 9a 5 i 2 g 15 5 3 Cove volcanic rocks on the western coast of Québec (David et al. 2002). R 12b 12b 10 6 5 3 83 m 12,11 9a 9a a i 5 15 v The Sachigo superterrane, with magmatic episodes from Meso- to 0 45 m e 15 12b 12a 12b 37 m 67 m r 12b 11 0 3 12a 3 Neoarchean age, encompasses a core terrane, the North Caribou terrane, 12a 5 9a 12a 14 a 2 RIVER 12b 6 3 14 FAWN and linear granite–greenstone domains on its south and north flanks that 12a b 3 5 7 33 a 5 85°30' 85°00' 84°30' 84°00' 83°30' 13 c a 12a record an outward growth through the Neoarchean. South of the Hudson 14 3 3 15 12a 12a 12,11 3 2 12,11 a Bay Lowland, major dextral transcurrent faults mark the boundaries 5 15 12a 0 7c RIVER 12b 5 2 5 54°N 94°W 12a 6 12a 14 12,11 15 b c 11 1 7 12b 3 S 3 11 12b 15 2 14 TU 14 3a 2 LL PROVINCIAL 10 SO 5 c 12a 8 -W U 12 2 3 15 5 6b 12b 5 T Robson 2 U c 3 N 11 H 3 3a 15 3 N 7 K 5 15 7 2 12a 3 11 E 12 Lake 11 12b a PROVINCIAL U 7 12b M NY 12 12 6 12a 7,8 12a 7 IN 14 11 5 PARK O 5 5 15 11 c 5 11 12a 3 5 12 N 0 54°N 15 c 6 2 8 8 53°15' 54°N 3 12a 15 15 5 F 2 15 12a 2 5 7c 6 5 A MACFAYDEN-2 6 5 5 6 PARK 7 U Sachigo 12a b 8 L KYLE-3 KYLE-2 12a T 5 ! 15 6 ! UNNAMED 7 12b Lake 2 12a 10 12 UNNAMED 5 5 2 12 6 UNIFORM-1 5 6 7 15 53°00' Ponask 15 b 5 15 12a 11 10 11,12 2 0 Lake 7 12a 10 GOLF-1 6 10 12 KYLE-5 15 12a b 5 10 12 GOOD FRIDAY 10 12 !! 6 Woolhead 12 11,12 Van de rb r in k 15 Portage 12 12 60 12b Lake ! Lake Bearskin Lake 5 12 c 6 MACFAYDEN-1 52 BRAVO-1 15 c 5 55 c 3 3 Lake 2 Sachigo Sandybank Wapekeka !! 3 2 c 11 2 15 c F 7 3 15 5 5 VICTOR-1 Sandymac 3 2 5 11 A TA NGO-1 Lake 1 15 2 5 Lake Reserve 2 r e 6 Lake 12a 5 15 c U v 3 5 Harrell Lake i 3 ! 54 5 7 3 U2 Kimberlite 2 R a ! ! 15 11 Kino L Trout !! !! AT-56 5 7 g TANGO EXTENSION !! T Big Trout Lake 5 i 15 53°00' !! 7 Wapekeka e 57,58 DELTA-1 12b Lake 5 ! w U1 Kimberlite 12a 11 11 11 (IR) ! e 11 5 Lake h 11 Sachigo Lake (I.R.) s 50 ! 15 11 7 12 ! !! ! Bearskin 10 Otter A CHARLIE-1 !! 12a 5 12 ! 7 c ! ! l 53 ! 6 7 3 Lake I.R. FAWN RIVER 11 5 12 e 51 5 2 5 n 7 12b Sachigo n KYLE-4 ! 12 15 12b 12a 10 a WHISKY DELTA-NORTH 52°45' 11 5 12 11 Misikeyask h ! Lake 15 C 5 12b 7 12 ia X-RAY 15 12 Lake Lake 11 5 kw ! 56 7 42 so ! ALPHA-1N 12 PROVINCIAL PARK Wapekeka ba Kitchenuhmaykoosib 41 Ta !! 5 Sachigo c YA NK EE -1 ! 3 5 East c 5 12 15 2 c Reserve 1 Lake 3 11 2 Aaki 84 ALPHA-1 5 3 10 2 7 6 Joint Lake 3 12a 2 11 Kasabonika T1 Kimberlite b 11 ZULU-1 Hayward 12 ! ! Lake I.R. X-RAY-1 12 Lake 12 5 Martin INDIA-1 Lake 12 15 c 12 5 3 11 3 Lake 2 3 11 12 12 7 52°45' 33 a 11 11 Cocos 12 a 11 15 12b 2 7 6 11 b 10 Hilton Lake 12 5 11 15 ! 11 Pasateko 12 5 5 Kasabonika Lake 15 ! 52°30' OPASQUIA 12 12b 11 10 15 12 15 49 15 7 c c Sabourin 3 3 Nemeigusabins 2 Croal PROVINCIAL 15 15 2 10 12 5 14 2 8 11 Lake Lake 12 6 12 b Shibogama 12 48 12 11 11 Lake ! 12 Lake 33 c 10 12 Lake PARK a 3 5 11 5 2 5 12 11 12 Long 94°W 93°W 92°W 91°W 90°W 89°W 88°W KYLE-1 52°30' !! 59 Scale 1:750 000

85°30' 85°00' 84°30' 84°00'

Figure 2. Close-up of the Attawapiskat cluster of kimberlite pipes on an aeromagnetic image that also highlights Proterozoic mafic (diabase) dikes. The close, linear proximity of most of the kimberlite pipes to one of the Matachewan dikes is most apparent. (See “Legend” for rock types and symbols.)