| Title | Variations in the textural facies of sulphide minerals in the Eagle's Nest Ni-Cu-(PGE) deposit, McFaulds Lake greenstone belt, Superior Province, Ontario: insights from microbeam scanning energy-dispersive
X-ray fluorescence spectrometry |
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| Licence | Please note the adoption of the Open Government Licence - Canada
supersedes any previous licences. |
| Author | Zuccarelli, N; Lesher, C M; Houlé, M G; Barnes, S J |
| 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. 165-179, https://doi.org/10.4095/326895  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 | 43C/11; 43C/12; 43C/13; 43C/14; 43D/09; 43D/10; 43D/15; 43D/16; 43E/01; 43E/02; 43E/07; 43E/08; 43F/03; 43F/04; 43F/05; 43F/06 |
| Lat/Long WENS | -87.0000 -85.0000 53.5000 52.5000 |
| Subjects | economic geology; mineralogy; geochemistry; Science and Technology; Nature and Environment; mineral deposits; nickel; copper; magmatic deposits; sulphide deposits; ore mineral genesis; mineralization;
ore controls; greenstone belts; bedrock geology; lithology; mafic rocks; ultramafic rocks; igneous rocks; volcanic rocks; komatiites; intrusive rocks; pyroxenites; websterites; gabbros; metamorphic rocks; metavolcanic rocks; tectonic setting;
tectonic history; rifts; magmatism; intrusions; dykes; emplacement; shear zones; textural analyses; x-ray fluorescence analyses; mineral assemblages; inclusions; fractional crystallization; fluid dynamics; fluid migration; mineral occurrences; host
rocks; facies; Archean; Eagle's Nest Deposit; Esker Intrusive Complex; Ring of Fire Intrusive Suite; McFaulds Lake Greenstone Belt; Superior Province; Black Thor Intrusion; Double Eagle Intrusion; Eagle's Nest Dyke; Koper Lake Subsuite; McFaulds
Shear Zone; Frank Shear Zone; Black Thor-Black Creek-Big Daddy Shear Zone; platinum group elements; Precambrian; Proterozoic |
| Illustrations | location maps; geoscientific sketch maps; schematic sections; tables; photomicrographs |
| Program | Targeted Geoscience Initiative (TGI-5) Nickel-copper-PGE-chromium systems |
| Released | 2020 09 08; 2023 03 17 |
| Abstract | The Eagle's Nest Ni-Cu-(PGE) deposit occurs within the 2.73 Ga Esker intrusive complex of the Ring of Fire intrusive suite, in the McFaulds Lake greenstone belt of northern Ontario. Sulphide
mineralization occurs along the northwestern margin of a subvertical ~500 m wide (north-south) x 1500 m deep komatiitic ultramafic body composed of harzburgite+/-lherzolite+/-wehrlite that is interpreted to represent a
structurally rotated, originally subhorizontal blade-shaped dyke. Disseminated (<15 wt% sulphide), net (15-35 wt% sulphide), and lesser semi-massive (50-80 wt% sulphide) and massive (>80 wt% sulphide) -textured sulphides have been characterized using
microbeam scanning energy-dispersive X-ray fluorescence spectrometry (uXRF). The images produced by this process have identified the abundances and locations of Fe, Ni, Cu, Ca, Si, and Cr within different minerals in 11 samples with representative
sulphide textures: disseminated, leopard net-textured (containing bimodal coarse- and fine-grained olivine), pinto net-textured (containing bimodal coarse orthopyroxene and fine olivine), inclusion net-textured (containing coarse inclusions of
peridotite), disrupted net-textured (containing pyroxenite invading leopard and pinto net-textured sulphides), semi-massive (containing inclusions of peridotite, pyroxenite, gabbro, and net-textured sulphides), and massive. All sulphide textures
typically contain magmatic assemblages of pyrrhotite-pentlandite-chalcopyrite-magnetite+/-chromite. Notable differences include small ellipsoidal chromite inclusions only in facies with disseminated textures, little to no clinopyroxene in leopard
net-textures, abundant clinopyroxene in invasive pyroxenite in disrupted net-textures, high-Cr orthopyroxene oikocrysts in pinto net-textures, and variable degrees of segregation of Cu-rich residual sulphide liquid from fractionally crystallizing
Fe-Ni-rich monosulphide solid solution, more in disrupted and inclusion net-textures than in disseminated textures or leopard or pinto net-textures. The wide variety of net textures, the abundance of inclusions, and the invasive pyroxenite indicate a
complex history for the magmatic plumbing system. Inclusions and late-stage pyroxenitic melt may have physically facilitated migration of residual sulphide liquid from monosulphide solid solution, and the emplacement of the late pyroxenite may have
slowed cooling and/or reheated the mineralization. Many of these details are less evident visually in slabbed cores or polished thin sections, highlighting the usefulness of uXRF in interpreting the genesis and beneficiation of texturally complex
magmatic Ni-Cu-PGE ores. |
| 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 | 326895 |
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