| Title | The Midcontinent Rift and its mineral systems: overview and temporal constraints of Ni-Cu-PGE mineralized intrusions |
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| Licence | Please note the adoption of the Open Government Licence - Canada
supersedes any previous licences. |
| Author | Bleeker, W ;
Smith, J; Hamilton, M; Kamo, S; Liikane, D; Hollings, P;
Cundari, R; Easton, M; Davis, D |
| 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. 7-35, https://doi.org/10.4095/326880  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 | Ontario |
| NTS | 41J; 41K; 41N; 41O; 42B; 42C; 42D; 42F; 42G; 42J; 42K; 42L; 52A; 52B; 52G; 52H; 52I; 52J |
| Area | Lake Superior; Michigan; Wisconsin; Minnesota; Canada; United States of America |
| Lat/Long WENS | -92.0000 -82.0000 51.0000 46.0000 |
| Subjects | economic geology; tectonics; geochronology; geophysics; Science and Technology; Nature and Environment; mineral deposits; nickel; copper; magmatic deposits; sulphide deposits; ore mineral genesis;
mineralization; ore controls; modelling; radiometric dating; uranium lead dating; bedrock geology; lithology; igneous rocks; tholeiites; intrusive rocks; mafic rocks; ultramafic rocks; kimberlites; gabbros; carbonatites; tectonic setting; tectonic
history; rifts; magmatism; intrusions; dykes; sills; provenance; mantle; drillholes; alkalinity; geophysical interpretations; magnetic interpretations; Midcontinent Rift; Superior Province; Crystal Lake Intrusion; Current Lake Intrusive Complex;
Sunday Lake Intrusion; Tamarack Intrusive Complex; Bovine Igneous Complex; Duluth Complex; Pigeon River Dyke Swarm; Portage Lake Volcanic Group; Thunder Bay North Complex; Coldwell Complex; Eagle Intrusion; Eagle East Intrusion; Cloud River Dykes;
Logan Sills; Mount Josephine Dyke; Mount Mollie Dyke; Echo Lake Intrusion; Mellen Complex; Beaver Bay Intrusion; Sonju Lake Intrusion; platinum group elements; Precambrian; Proterozoic |
| Illustrations | geoscientific sketch maps; tables; photographs; photomicrographs; Concordia diagrams; cross-sections |
| Program | Targeted Geoscience Initiative (TGI-5) Nickel-copper-PGE-chromium systems |
| Released | 2020 09 08; 2023 03 17 |
| Abstract | In an effort to better understand the spatial and temporal distributions of mineralized intrusions of the Midcontinent Rift (MCR), and what controls their style of magmatic Ni-Cu-PGE sulphide
mineralization, we have compiled an overview of all known intrusions and their ages. We provide new U-Pb ages for more than ten such intrusions and/or their associated dyke systems. A number of these investigations are still in progress, and all ages
should be treated as preliminary. Nevertheless, we discuss new results on the mineralized Current Lake, Sunday Lake, Tamarack, and Crystal Lake intrusions, as well as the Bovine Igneous Complex on the southern flank of the MCR. These new results, as
well as improved ages for a number of the associated major dyke swarms and sill complexes (e.g. the Logan Sills), favour a relatively sharp onset of high-volume mafic-ultramafic magmatism in the MCR at ca. 1110 to 1106 Ma, although a few of the older
age "outliers" remain to be tested. Mineralized intrusions are not confined to any specific magmatic pulse but are distributed through time, correlating with the major magmatic pulses at 1110-1106 Ma (e.g. Current Lake), 1104 Ma (Tamarack), of course
at 1099 Ma (Duluth Complex), to as young as 1093 Ma (Crystal Lake). All these intrusions are dynamic, multi-phase, feeder-type systems. A major "post-Duluth Complex" reorganization in the magmatic plumbing system is identified starting at ca.
1097-1096 Ma, with magmatism contracting into a linear feeding zone along the northwestern shore of Lake Superior-the "north shore magmatic feeder zone" or NSMFZ-cored by the major Pigeon River dyke swarm. This feeder zone, a major magmatic fissure
system, likely fed the entire lava flow field of the Portage Lake Volcanic Group, which extends to both sides of Lake Superior. |
| 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 | 326880 |
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