| Title | Trace elements in Fe-oxide minerals from fertile and barren igneous complexes: investigating their use as a vectoring tool for Ni-Cu-PGE sulphide mineralization |
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| Licence | Please note the adoption of the Open Government Licence - Canada
supersedes any previous licences. |
| Author | Dare, S A S; Ames, D E ; Lightfoot, P C; Barnes, S-J; Beaudoin, 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.
175-185, https://doi.org/10.4095/296688  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; Newfoundland and Labrador |
| NTS | 14C; 14D; 41I |
| Area | Voisey's Bay; Sudbury |
| Lat/Long WENS | -82.0000 -80.0000 47.0000 46.0000 |
| Lat/Long WENS | -64.0000 -60.0000 57.0000 56.0000 |
| Subjects | metallic minerals; igneous and metamorphic petrology; modelling; nickel; platinum; chromium; ore mineral genesis; metallogeny; iron oxides; magnetite; ilmenite; copper; sulphides; trace element
geochemistry; trace elements; intrusive rocks; copper; Newark Island Layered Intrusion; Nain province; Superior Province; Sudbury Igneous Complex; Eastern Deep Intrusion |
| Illustrations | analyses |
| Program | Targeted Geoscience Initiative (TGI-4) Mafic-Ultramafic Ore Systems |
| Released | 2015 06 22; 2023 03 17 |
| Abstract | The aim of this study was to develop a new technique to determine the fertility of mafic intrusions for Ni-Cu-PGE sulphide mineralization using the mineral chemistry of Fe oxides in the silicate host
rocks. A suite of 25 trace elements was determined in magnetite and ilmenite, by laser ablation ICP-MS at LabMaTer (UQAC), from a variety of barren and fertile igneous complexes. Two of Canada’s largest Ni deposits, the 1.85 Ga Sudbury Igneous
Complex and its vast Ni-Cu-PGE mineral district (Ontario) and the 1.34 Ga Eastern Deeps Intrusion-hosting Ni-Cu-Co sulphide mineralization at Voisey’s Bay (Newfoundland), were selected for study. Samples chosen from igneous complexes that are barren
of significant Ni sulphide mineralization comprise layered mafic intrusions (Bushveld Complex, South Africa and Sept Iles, Quebec) and anorthosite suites (Saguenay-Lac-St.-Jean, Quebec) that host Fe-Ti-V-P oxide deposits, some of which contain trace
amounts of Ni-Cu-PGE sulphides. Mafic rocks of the 1.33 Ga Newark Island layered intrusion (Labrador) were also studied as they are similar in composition and setting to Voisey's Bay but devoid of significant Ni sulphide mineralization.
In
sulphide-undersaturated magmas, Cu, Sn, Mo, and Zn are incompatible during fractionation and thus increase in concentration in late-crystallizing magnetite and ilmenite. Upon sulphide saturation and the formation of a trace amount of sulphide, only
Cu is depleted in the silicate magma relative to the incompatible elements. Copper depletion, as recorded by Fe oxides, is a sensitive indicator of sulphide saturation and can be diagnostic of whether a Ni-bearing sulphide deposit will have formed if
the Cu depletion occurred early during fractionation. In contrast, Ni and Co are compatible during fractionation, partitioning into olivine, orthopyroxene, and, where present, sulphide, and their concentrations steadily decrease in the Fe oxides,
together with Cr, as crystallization proceeds. Iron oxides from barren igneous complexes plot on a single Ni-Cr trend but Fe oxides from fertile complexes (those hosting Ni sulphide deposits) plot on a parallel Ni-Cr trend displaced to lower Ni
concentration. Nickel depletion is therefore recorded in Fe oxides and has the potential to identify intrusions with buried Ni-sulphide mineralization. The advantages of using Fe oxides as an exploration tool include their resistance to post-magmatic
processes, such as alteration, and their preservation and easy recovery from glacial till and heavy mineral separates. |
| 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 | 296688 |
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