The relationship between chlorapatite and PGE-rich cumulates in layered intrusions; the Klappsjo Gabbro, north-central Sweden, as a case study

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doi: 10.2113/gscanmin.42.2.279
Authors:Meurer, William P.; Hellstrom, Fredrik A.; Claeson, Dick T.
Author Affiliations:Primary:
Department of Earth Sciences, Goteborg, Sweden
Other:
University of Houston, United States
McGill University, Canada
Volume Title:Platinum-group elements; petrology, geochemistry, mineralogy
Volume Authors:Mungall, James E., editor; Meurer, William E.; Martin, Robert F.
Source:The Canadian Mineralogist, Vol.42(Part 2), p.279-289; 9th international platinum symposium, Billings, MT, July 25-29, 2002, edited by James E. Mungall, William E. Meurer and Robert F. Martin. Publisher: Mineralogical Association of Canada, Ottawa, ON, Canada. ISSN: 0008-4476
Publication Date:2004
Note:In English. 34 refs.; illus., incl. 1 table, sketch map
Summary:The Kläppsjö gabbro hosts two known horizons that show enrichments in PGE and Au, and are associated with chlorapatite (Cl 0.32-5.95 wt %). Unlike the well-developed J-M and Merensky reefs, there is no evidence that the chlorapatite or the metal concentrations are the products of large-scale degassing of interstitial liquid and chromatic transport. Variations in mineral compositions and the positions of the metal-enriched horizons indicate that sulphide saturation induced by magma mixing is equally unlikely. The data can be explained by injection of a magma enriched in PGE, Au and Cl relative to typical basalt; this magma ponded on the floor of the intrusion, and sulphide accumulations led to the irregular distribution of metal concentrations. Ultramafic cumulates both above and below the enriched cumulates lack the chlorapatite, but are otherwise similar. These data reinforce the general relationships of chlorapatite with mineralization in layered intrusions, but suggest that large-scale degassing is not the only explanation for this association. [R.A.H.]
Sections:Economic minerals and ore deposits; Mineral data
Subsections:Metallic deposits: specific; Non-silicates
Subjects:Archean; Chlorapatite; Chlorine; Cumulates; Gabbros; Halogens; Igneous rocks; Intrusions; J-M Reef; Layered intrusions; Metals; Phosphates; Platinum group; Platinum minerals; Plutonic rocks; Precambrian; Sulfides; Africa; Europe; Merensky Reef; Scandinavia; South Africa; Southern Africa; Sweden; Western Europe; Klappsjo Gabbro
Coordinates:N634100 N634100 E0171500 E0171500
Abstract Numbers:04M/2883
Record ID:2007049918
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
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