Skip to Main Content
Skip Nav Destination
GEOREF RECORD

On the mechanisms for low-sulfide, high-platinum group element and high-sulfide, low-platinum group element mineralization in the Eastern Gabbro, Coldwell Complex, Canada; evidence from textural associations, S/Se values, and platinum group element concentrations of base metal sulfides

M. J. Brzozowski, I. M. Samson, J. E. Gagnon, D. J. Good and R. L. Linnen
On the mechanisms for low-sulfide, high-platinum group element and high-sulfide, low-platinum group element mineralization in the Eastern Gabbro, Coldwell Complex, Canada; evidence from textural associations, S/Se values, and platinum group element concentrations of base metal sulfides
Economic Geology and the Bulletin of the Society of Economic Geologists (March 2020) 115 (2): 355-384

Abstract

The Eastern Gabbro, Coldwell Complex, hosts several geochemically and mineralogically distinct Cu-platinum group element (PGE) deposits, including the high-grade W Horizon (>100 ppm Pd-Pt-Au over 2 m). Several magmatic and/or hydrothermal models have previously been proposed to explain the range of enrichment in PGEs observed in the Marathon deposit, but no work has integrated textural and compositional variations in sulfides to elucidate which of these models is most suitable. Additionally, comparatively little work has been done to characterize the genesis of Cu-PGE mineralization that occurs to the northwest of the Marathon deposit in the Eastern Gabbro. Through integration of base metal sulfide (BMS) mineralogy, texture, and trace element chemistry, a wide range of magmatic and postmagmatic processes have been characterized that contributed to the formation of these deposits. In all zones of mineralization in the Eastern Gabbro, chalcophile elements were remobilized from primary chalcopyrite by hydrothermal fluids and precipitated as secondary chalcopyrite, which occurs as a replacement of pyrrhotite and as intergrowths with hydrous silicates. BMSs in the mineralized zones in the Marathon deposit (Footwall zone, Main zone, and W Horizon) experienced higher R factors than those deposits located northwest of the Marathon deposit (Four Dams, Area 41, and Redstone), with BMSs in the W Horizon having experienced the highest R factors. The silicate melts from which the Footwall zone crystallized likely experienced some degree of sulfide segregation at depth, albeit to a much lesser degree than the northern deposits. Additionally, the melts from which the mineralized zones in the Marathon deposit crystallized were likely contaminated by high-S/Se Archean sedimentary rocks, whereas the northern deposits were likely contaminated by low-S/Se igneous and/or metamorphic rocks. BMSs in a chalcopyrite-rich pod located within the vicinity of the Coldwell Complex experienced both high R factors and high degrees of contamination (cf. W Horizon and Footwall zone, respectively). This study illustrates the complexity of processes that generate and modify mineralization in conduit-type Ni-Cu-PGE systems.


ISSN: 0361-0128
EISSN: 1554-0774
Coden: ECGLAL
Serial Title: Economic Geology and the Bulletin of the Society of Economic Geologists
Serial Volume: 115
Serial Issue: 2
Title: On the mechanisms for low-sulfide, high-platinum group element and high-sulfide, low-platinum group element mineralization in the Eastern Gabbro, Coldwell Complex, Canada; evidence from textural associations, S/Se values, and platinum group element concentrations of base metal sulfides
Affiliation: Nanjing University, School of Earth Sciences and Engineering, Nanjing, China
Pages: 355-384
Published: 202003
Text Language: English
Publisher: Economic Geology Publishing Company, Lancaster, PA, United States
References: 146
Accession Number: 2020-050965
Categories: Economic geology, geology of ore deposits
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 4 tables, geol. sketch maps
N48°44'30" - N48°52'60", W86°37'60" - W86°17'60"
Secondary Affiliation: University of Windsor, Department of Earth and Environmental Sciences, CAN, CanadaWestern University, Department of Earth Sciences, CAN, Canada
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2020, American Geosciences Institute. Abstract, Copyright, Society of Economic Geologists. Reference includes data from GeoScienceWorld, Alexandria, VA, United States
Update Code: 2020
Close Modal

or Create an Account

Close Modal
Close Modal