| Title | Geochemical composition of chromite from Alexo komatiite in the western Abitibi
greenstone belt: Implications for mineral exploration |
| Download | Downloads |
| |
| Licence | Please note the adoption of the Open Government Licence - Canada
supersedes any previous licences. |
| Author | Pagé, P; Barnes, S-J; Méric, J; Houlé, M G |
| Source | Targeted Geoscience Initiative 4: Canadian nickel-copper-platinum group elements-chromium ore systems -- fertility, pathfinders, new and revised models; by Ames, D E (ed.); Houlé, M G (ed.); Geological Survey of Canada, Open File 7856, 2015 p.
187-195, https://doi.org/10.4095/296689  Open Access |
| Image |  |
| Year | 2015 |
| Publisher | Natural Resources Canada |
| Document | open file |
| Lang. | English |
| Media | on-line; digital |
| Related | This publication is contained in Targeted Geoscience
Initiative 4: Canadian nickel-copper-platinum group elements-chromium ore systems -- fertility, pathfinders, new and revised models |
| File format | pdf |
| Province | Ontario |
| NTS | 42A/10 |
| Area | Porquis Junction |
| Lat/Long WENS | -81.0000 -80.7333 48.7500 48.5833 |
| Subjects | geochemistry; igneous and metamorphic petrology; chromite; mineral exploration; whole rock geochemistry; basalts; volcanic rocks; komatiites; chromium geochemistry; osmium; iridium; ruthenium; rhodium;
Abitibi Greenstone Belt; Superior Province; Alexo komatiite |
| Illustrations | analyses |
| Program | Targeted Geoscience Initiative (TGI-4) Mafic-Ultramafic Ore Systems |
| Released | 2015 06 22; 2023 03 17 |
| Abstract | This study, which focuses on the composition of chromite from mineralized and unmineralized komatiitic flows and sills from the Alexo Mine area in Dundonald Township, within the western Abitibi
greenstone belt, aims to develop new exploration tools for poorly exposed mineralized komatiitic systems. It is possible to clearly identify chromite derived from massive sulphide (having very high Cr# and depleted Ru content) from chromite derived
from barren and poorly mineralized samples based on its composition. LA-ICPMS analyses show that chromite from massive sulphide are depleted in Al, Ni, and Mg, and are enriched in Ti, Zn, Mn, Fe and V compared to chromite from barren samples;
however, alteration can also modify chromite chemistry. Samples from the Hart deposit are pervasively altered and their chromite compositions are enriched in Fe, Zn, Co, and Mn, and are depleted in Mg. We propose a binary diagram of Ni/Mn versus
Ni/Cr ratios which can be used to clearly discriminate between sulphide segregation prior to chromite crystallization and later superimposed alteration. Mass balance calculations show that chromite does fractionate and concentrate Ir-group
platinum-group elements (IPGE: Os, Ir, Ru) and Rh but that chromite contribution to the whole-rock IPGE and Rh budget is rather limited, and for mineralized samples, this contribution is even smaller. From these results, it is clear that IPGE+Rh-rich
phases (nano- to micro- platinum-group minerals) are needed to account for the IPGE and Rh contents in whole-rock geochemistry. |
| Summary | (Plain Language Summary, not published)
The Targeted Geoscience Initiative (TGI-4) is a collaborative federal geoscience program that provides industry with the next generation of geoscience
knowledge and innovative techniques to better detect buried mineral deposits, thereby reducing some of the risks of exploration. This volume summarizes 22 research activities completed under the TGI-4 Ni-Cu-PGE-Cr ore systems project that focused on
revised and new geologic models for Ni-Cu-PGE, PGE-Cu and Cr deposits, innovative techniques for determining potential fertility of intrusion (Ni-Cu-PGE), and defining pathfinders for Ni-Cu-PGE mineralization. |
| GEOSCAN ID | 296689 |
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