| Title | Geology and geochemistry of mafic and ultramafic bodies in the Shebandowan mine area, Wawa-Abitibi terrane: implications for Ni-Cu-(PGE) and Cr-(PGE) mineralization, Ontario and Quebec |
| Download | Downloads |
| |
| Licence | Please note the adoption of the Open Government Licence - Canada
supersedes any previous licences. |
| Author | Kuster, K; Lesher, C M; Houlé, M G |
| Source | Geological Survey of Canada, Scientific Presentation 130, 2022, 25 pages, https://doi.org/10.4095/329394  Open Access |
| Image |  |
| Year | 2022 |
| Publisher | Natural Resources Canada |
| Meeting | Harquail School of Earth Sciences Graduate Symposium; April 2021 |
| Document | serial |
| Lang. | English |
| Media | digital; on-line |
| File format | pdf |
| Province | Quebec |
| NTS | 32D/09 |
| Lat/Long WENS | -78.3603 -78.0331 48.6331 48.5381 |
| Subjects | economic geology; geochemistry; tectonics; regional geology; structural geology; mineralogy; Science and Technology; Nature and Environment; mineral exploration; mineral potential; mineral deposits;
nickel; copper; chromium; sulphide deposits; ore mineral genesis; mineralization; ore controls; bedrock geology; lithology; mafic rocks; ultramafic rocks; igneous rocks; volcanic rocks; lava flows; basalts; komatiites; intrusive rocks; metamorphic
rocks; serpentinites; schists; structural features; lineations; faults; tectonic setting; tectonic history; magmatism; volcanism; intrusions; sills; metamorphism; alteration; aluminum geochemistry; magnesium geochemistry; mantle; models; fluid
dynamics; lithogeochemistry; host rocks; sulphides; oxides; Archean; Shebandowan Mine; Wawa-Abitibi Terrane; Shebandowan Greenstone Belt; Superior Province; Shebandowan Assemblage; Kashabowie Assemblage; Burchell Assemblage; Greenwater Assemblage;
Crayfish Creek Fault; platinum group elements; Precambrian; Proterozoic |
| Illustrations | geoscientific sketch maps; stratigraphic columns; sections; photographs; plots; photomicrographs; ternary diagrams; tables |
| Program | Targeted Geoscience Initiative (TGI-6) Ore systems |
| Released | 2022 02 23 |
| Abstract | The Shebandowan Ni-Cu-(PGE) deposit occurs in the Shebandowan greenstone belt in the Wawa-Abitibi terrane. This deposit is one of a few economic Ni-Cu-(PGE) deposits in the Superior Province and one of
a very few deposits worldwide that contains both Ni-Cu-(PGE) and Cr-(PGE) mineralization. The mafic-ultramafic successions in the area comprise abundant flows and sills of tholeiitic basalt and lesser Al-undepleted komatiite (MgO >18 wt%, Al2O3/TiO2
= 15-25), the latter indicating separation from mantle sources at shallow levels. Siliceous high-Mg basalts (MgO 8-12 wt%, SiO2 > 53 wt%, TiO2 < 1.2 wt%, La/Sm[MN] < 1-2) are relatively abundant in the area and likely represent crustally contaminated
komatiites. Ultramafic bodies in the Shebandowan mine area comprise at least three or four komatiitic sills (A-B, C, D) and at least two komatiitic flows (E, F), all of which are altered to serpentinites or talc-carbonate schists with relict igneous
chromite and rare relict igneous orthopyroxene-clinopyroxene. Unit A-B contains pentlandite-pyrrhotite-chalcopyrite-pyrite-magnetite mineralization, occurring as massive sulfides, sulfide breccias, or stringers, and subeconomic chromite
mineralization in contorted massive bands varying from a few millimetres up to 10 metres thick. The localization of massive and semi-massive Ni-Cu-(PGE) ores along the margins of Unit A and the paucity of disseminated and net-textured ores suggest
tectonic mobilization. Chromite is typically zoned with Cr-Mg-Al-rich (chromite) cores and Fe-rich (ferrichromite/magnetite) rims due to alteration and/or metamorphism, but rarely contains amoeboid magnetite cores. The thickness of chromite in Unit B
is too great to have crystallized in cotectic proportion from the komatiitic magma and a model involving dynamic upgrading of magnetite xenoliths derived from interflow oxide facies iron formations is being tested. |
| Summary | (Plain Language Summary, not published)
Under the Targeted Geoscience Initiative (TGI) Program of the Geological Survey of Canada (GSC), this study aims to better understand how nickel (Ni),
copper (Cu) and platinum-group elements (PGE) mineralization form in the Canadian Shield. This specific contribution summarize preliminary results from a geological and geochemical compilation around the Shebandowan Ni-Cu-(PGE) mine in the Thunder
Bay area in northwestern Ontario. This deposit is one of numerous economic Ni-Cu-(PGE) deposits in the Superior Province but is only one of very few deposits that contains both Ni-Cu-(PGE) and Cr-(PGE) mineralization. |
| GEOSCAN ID | 329394 |
|
|