| Title | Genesis of chromite deposits by dynamic upgrading of Fe ± Ti oxide xenocrysts |
| |
| Author | Lesher, C M; Carson, H J E; Houlé, M G |
| Source | Geology vol. 47, no. 3, 2019 p. 207-210, https://doi.org/10.1130/G45448.1  Open Access |
| Image |  |
| Year | 2019 |
| Alt Series | Natural Resources Canada, Contribution Series 20190118 |
| Publisher | Geological Society of America |
| Document | serial |
| Lang. | English |
| Media | paper; on-line; digital |
| File format | pdf (Adobe® Reader®); html |
| Province | Ontario |
| NTS | 43D/16 |
| Lat/Long WENS | -86.2278 -86.1783 52.7969 52.7722 |
| Subjects | economic geology; igneous and metamorphic petrology; Science and Technology; mineral deposits; chromite; magmatic deposits; ore mineral genesis; mineralization; modelling; oxides; iron oxides; titanium;
partial melting; iron formations; komatiites; chromium; magmas; fluid dynamics; Black Thor Intrusive Complex; Superior Province |
| Illustrations | models; plots; photomicrographs; schematic models |
| Program | Targeted Geoscience Initiative (TGI-5) Nickel-copper-PGE-chromium ore systems - architecture - Cr-bearing systems |
| Released | 2019 01 18 |
| Abstract | Most magmatic chromite deposits, particularly those in stratiform layered ultramafic-mafic intrusions, are interpreted to have formed by processes that decrease the solubility of chromite. However, such
models have difficulty in explaining the great thicknesses (up to 10 m) of chromite mineralization at Inyala and Railway Block (Zimbabwe), Ipueira-Medrado (Brazil), Uitkomst (South Africa), and Sukinda (India), and the very great (up to 100 m)
thicknesses of chromitite at Kemi (Finland) and in the Black Thor Intrusive Complex (Canada). We propose a new process that involves partial melting of Fe ± Ti oxide-rich rocks (oxide-facies iron formation or ferrogabbro) and conversion of
fine-grained oxide to chromite by reaction with Cr-rich komatiitic magma in a dynamic magma conduit. This process is analogous to the widely accepted model for the upgrading of barren iron-sulfide xenomelts to form magmatic nickel-copper-platinum
group element deposits. We demonstrate that this process is geologically, physically, and chemically feasible, that it probably occurred in the Black Thor Intrusive Complex, and that it may have applications elsewhere. |
| GEOSCAN ID | 314784 |
|
|