| Title | The composition of magnetite in Archean mafic-ultramafic intrusions within the Superior Province |
| Download | Downloads |
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| Licence | Please note the adoption of the Open Government Licence - Canada
supersedes any previous licences. |
| Author | Sappin, A -A ;
Houlé, M G |
| Source | Targeted Geoscience Initiative 5: Advances in the understanding of Canadian Ni-Cu-PGE and Cr ore systems - Examples from the Midcontinent Rift, the Circum-Superior Belt, the Archean Superior Province, and
Cordilleran Alaskan-type intrusions; by Bleeker, W (ed.);
Houlé, M G (ed.); Geological Survey of Canada, Open File 8722, 2020 p. 181-196, https://doi.org/10.4095/326896  Open Access |
| Image |  |
| Year | 2020 |
| Publisher | Natural Resources Canada |
| Document | open file |
| Lang. | English |
| Media | on-line; digital |
| Related | This publication is contained in Targeted Geoscience
Initiative 5: Advances in the understanding of Canadian Ni-Cu-PGE and Cr ore systems - Examples from the Midcontinent Rift, the Circum-Superior Belt, the Archean Superior Province, and Cordilleran Alaskan-type intrusions |
| File format | pdf |
| Province | Manitoba; Ontario; Quebec |
| NTS | 22E; 22K; 22L; 22M; 22N; 22O; 23; 24A; 24B; 24C; 24D; 24E; 24F; 24G; 24J; 24K; 24L; 24M; 24N; 25C; 25D; 25E; 25F; 31E; 31J; 31K; 31L; 31M; 31N; 31O; 32; 33; 34; 35A; 35B; 35C; 35D; 35E; 35F; 35G; 35H; 41F;
41G; 41H; 41I; 41J; 41K; 41N; 41O; 41P; 42; 43; 44; 52; 53; 54A; 54B; 54C; 54D; 62G; 62H; 62I; 62J; 62O; 62P; 63A; 63B; 63G; 63H; 63I; 63J; 63O; 63P; 64A; 64B |
| Lat/Long WENS | -100.0000 -64.0000 62.0000 45.0000 |
| Subjects | economic geology; mineralogy; geochemistry; stratigraphy; Science and Technology; Nature and Environment; mineral exploration; exploration guidelines; mineral deposits; iron; titanium; vanadium;
phosphorus; magmatic deposits; sulphide deposits; ore mineral genesis; mineralization; ore controls; magnetite; petrogenesis; bedrock geology; lithology; igneous rocks; intrusive rocks; mafic rocks; ultramafic rocks; komatiites; pyroxenites; tectonic
setting; greenstone belts; magmatism; intrusions; dykes; emplacement; hydrothermal deposits; fluid dynamics; crystal fractionation; inclusions; exsolution; magmas; host rocks; mineral associations; minor element geochemistry; trace element
geochemistry; core samples; grab samples; electron probe analyses; mass spectrometer analysis; Archean; Superior Province; Bird River-Uchi-Oxford-Stull-La Grande Riviere-Eastmain (BUOGE) Superdomain; Wawa-Abitibi Terrane; Neoarchean; Mesoarchean;
Rivière Bell Complex; Lac Doré Complex; Croal Lake Intrusion; Big Mac Intrusion; Butler Intrusion; Wabassi Main Intrusion; Highbank-Fishtrap Intrusive Complex; Ring of Fire Intrusive Suite; Ekwan River Subsuite; Baie Chapus Pyroxenite; Mayville
Intrusion; Eagle's Nest Intrusion; Oxtoby Lake Intrusion; Bird River Intrusive Suite; North Caribou Terrane; Abitibi Greenstone Belt; Precambrian |
| Illustrations | geoscientific sketch maps; tables; geochemical plots |
| Program | Targeted Geoscience Initiative (TGI-5) Nickel-copper-PGE-chromium systems |
| Released | 2020 09 08; 2023 03 17 |
| Abstract | The mineral chemistry of magnetite from eleven Archean mafic, mafic-ultramafic, and ultramafic intrusions within the Superior Province was determined to be used as a petrogenetic indicator and to
identify the most prospective areas for exploration of Fe-Ti-V and Fe-Ti-P mineralization. The composition of magnetite is influenced by the presence of exsolutions and inclusions (e.g. ilmenite, Al-spinel), the type of parental melt (e.g.
komatiitic, basaltic) and its Ti contents (e.g. high-Ti or low-Ti parental magmas), and the element partitioning with co-crystallized minerals (e.g. clinopyroxene) or previously crystallized minerals (e.g. chromite). The overall composition of
magnetite, however, appears to be mainly independent of the host-rock type. The composition of magnetite in compatible (e.g. Mg, Co, V, Ni, and Cr) and incompatible (e.g. Al, Ga, Mn, Ti, Zn) elements during fractionation processes also provides
useful information about the degree of differentiation of the host intrusions. Among the studied intrusions with a mafic-dominated composition, the Riviere Bell and Lac Dore complexes appear to be the most evolved, whereas the Croal Lake, Big Mac,
Butler, and Wabassi Main intrusions and the Highbank-Fishtrap intrusive complex are the most primitive. Furthermore, the variation of the minor and trace element contents of the magnetite could be used to determine the internal stratigraphy within
the mafic to ultramafic intrusions. For example, in the mafic-dominated Big Mac intrusion and in the ultramafic-dominated Baie Chapus Pyroxenite, the more vent-proximal facies appear to be located to the north and to the east, respectively. In
addition, the V and Ni+Cr contents of magnetite from the Big Mac intrusion suggest that the northern part of this intrusion is a prospective area for Fe-Ti-V mineralization, whereas the southern part has more potential for Fe-Ti-P mineralization. In
the Baie Chapus Pyroxenite, the concentrations in V and Ni+Cr in magnetite support the prospectivity of this intrusion for Fe-Ti-V mineralization. Magnetite from the oxide-bearing mafic to ultramafic rocks and the semi-massive to massive Fe-Ti oxide
layers have lower Ti+V values than expected, with magnetite compositions plotting within the fields for hydrothermal deposits in Ni/(Cr+Mn) versus Ti+V, Ca+Al+Mn versus Ti+V, and Ni+Cr versus Ti+V discrimination diagrams. Considering that the Fe-Ti-V
deposit fields in these diagrams were mostly defined based on Fe-oxides hosted within Proterozoic and Phanerozoic Fe-Ti deposits, the preliminary results presented here suggest there may be a specific signature for magnetite from Archean
Fe-Ti-V-oxide-bearing intrusions. However, further work is required to confirm this distinct signature to the Archean. |
| Summary | (Plain Language Summary, not published)
Key objectives of Phase 5 (2015-2020) of the Targeted Geoscientific Initiative (TGI) program of Natural Resources Canada and the Geological Survey of
Canada were to generate new knowledge, methodologies, and models to enhance the exploration industry's ability to detect buried ore deposits and extensions of existing ore systems, and to provide models for targeting new deposit areas. This synthesis
volume contains nine individual papers that discuss deposit scale to magmatic system fundamentals from various Canadian examples pertaining to the TGI-5 Ni-Cu-PGE-Cr project. |
| GEOSCAN ID | 326896 |
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