A gold-bearing horizon in the Kap Edvard Holm Complex, East Greenland

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doi: 10.2113/gsecongeo.90.5.1288
Authors:Bird, Dennis K.; Arnason, John G.; Brandriss, Mark E.; Nevle, Richard J.; Radford, Geoff; Bernstein, Stefan; Gannicott, Robert A.; Kelemen, Peter B.
Author Affiliations:Primary:
Stanford University, Department of Geological and Environmental Sciences, Stanford, CA, United States
Dihedral Exploration, United States
Danish Lithosphere Center, Denmark
Platinova Resources, Canada
Woods Hole Oceanographic Institution, United States
Volume Title:Economic Geology and the Bulletin of the Society of Economic Geologists
Source:Economic Geology and the Bulletin of the Society of Economic Geologists, 90(5), p.1288-1300. Publisher: Economic Geology Publishing Company, Lancaster, PA, United States. ISSN: 0361-0128
Publication Date:1995
Note:In English. 47 refs.; illus., incl. strat. col., 4 tables, sketch map
Summary:An association of Au and PGE mineralization in the early Tertiary gabbros of the Kap Edward Holm complex is reported. Gabbros containing up to 6 ppm Au occur in a stratabound interval several metres thick and extending >><[dollar]I> 6 km in strike length in the Lower Layered series of the complex. The Au occurs as anhedral grains of Au-Ag-Cu metal ∼ 5 µm in diameter. Metal grains range 85-96 wt.% Au and are typically enclosed in cumulus plagioclase and clinopyroxene. About half of the 38 gold grains observed in a single drill core are spatially associated with Cu-Fe sulphide inclusions, mainly intergrowths of digenite and bornite. The lower part of the Au-bearing horizon overlaps with a layer that contains Pt-Fe alloys and Pt-sulphides, -arsenides and -tellurides. Like the Au grains, Pt minerals occur near margins of cumulus schists and are typically close to Cu-Fe sulphide inclusions (mostly bornite-idaite). Total sulphide in the mineralized gabbros is up to ∼ 1% by volume. In outcrop the Au-bearing gabbros are indistinguishable, but in the 250 m above the mineralized horizon the Mg contents of olivine and augite and Cr of titanomagnetite increase. The authors suggest that the concentration and deposition of Au and Pt were spatially and temporally related to an influx of Mg-rich magma. Metasomatic reactions with meteoric hydrothermal solutions subsequently modified phase relations. - R. [M.F.P.]
Subjects:Cenozoic; Chemical composition; Gabbros; Gold ores; Igneous rocks; Lower Tertiary; Metal ores; Mineralization; Ore grade; Platinum ores; Plutonic rocks; Tertiary; Arctic region; East Greenland; Greenland; Kap Edvard Holm Complex; Willow Ridge
Abstract Numbers:96M/4003
Record ID:1996008595
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
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