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TitleRecent advances in fluid and melt inclusion and applied mineralogical research in the Sudbury mining camp: improving ore genesis models and exploration success
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LicencePlease note the adoption of the Open Government Licence - Canada supersedes any previous licences.
AuthorHanley, J J; MacMillan, M A; Kerr, M J; Watts, K M; Warren, M R; Ames, D EORCID logo
SourceTargeted Geoscience Initiative 4: Canadian nickel-copper-platinum group elements-chromium ore systems -- fertility, pathfinders, new and revised models; by Ames, D EORCID logo (ed.); Houlé, M G (ed.); Geological Survey of Canada, Open File 7856, 2015 p. 209-231, https://doi.org/10.4095/296691 Open Access logo Open Access
Year2015
PublisherNatural Resources Canada
Documentopen file
Lang.English
Mediaon-line; digital
RelatedThis publication is contained in Targeted Geoscience Initiative 4: Canadian nickel-copper-platinum group elements-chromium ore systems -- fertility, pathfinders, new and revised models
File formatpdf
ProvinceOntario
NTS41I
AreaSudbury
Lat/Long WENS -82.0000 -80.0000 47.0000 46.0000
Subjectsgeochemistry; igneous and metamorphic petrology; analytical methods; nickel; platinum; modelling; ore mineral genesis; metallogeny; chromium; copper; stable isotope studies; fluid inclusions; mineralization; apatite; biotite; Bird River Greenstone Belt; Abitibi Greenstone Belt; Nain province; Superior Province; Sudbury Igneous Complex
ProgramTargeted Geoscience Initiative (TGI-4) Mafic-Ultramafic Ore Systems
Released2015 06 22
AbstractA variety of microanalytical techniques (LA-ICP-MS, microthermometry, SIMS) were applied to resolve uncertainties about the chemical evolution of the Sudbury Igneous Complex (SIC) melt sheet and its associated hydrothermal systems. In the SIC sublayer and main mass, silicate melt inclusions in early apatite cumulate grains preserve evidence for high-temperature (>1100°C) immiscibility between Fe-rich and Sirich liquids. Melt inclusions record the base metal (Ni, Cu, Co) endowment of the melt sheet prior to and after sulphide saturation and allow quantification of trace element partitioning at various stages during meltsheet evolution, and prediction of the likelihood that an offset dyke contains or does not contain sulphide ore deposits locally. Melt inclusions were deemed unaffected by post-cumulus processes, providing an opportunity to characterize primary magmatic processes otherwise obscured by 1.85 Ga of metamorphism, deformation, and hydrothermal alteration. In the sublayer, analysis of the trace element chemistry of alteration, metamorphic and igneous biotite identified the chemical signature of biotites associated with the host inclusion-rich quartz diorite offset-style Ni-Cu-platinum-group element (PGE) sulphide orebodies, characterized by elevated Ni, Cu, and Ni/Cr ratios. Trace metal analysis of biotite allows differentiation between this key rock type and barren quartz diorite that is otherwise compositionally and textually comparable. In footwall Cu-Ni-PGE ore deposits, alteration, fluid inclusion, and stable isotope studies provide a systematic description of "low-sulphide" deposit style. Hydrothermal sulphide precipitation, a process recorded in alteration vein styles, was associated with mixing of oxidized, 18O-enriched, high salinity metal-rich fluids with cooler, reduced, 18O-depleted, high-Ca groundwaters. Recognition of this mixing process through isotope mapping, fluid inclusion microthermometry, and alteration mineral chemistry provides a means to identify metal-precipitation fronts within the complex footwall environment.
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 ID296691

 
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