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Gold and platinum in shales with evidence against extraterrestrial sources of metals

Chemical Geology

By:
, , , ,
DOI: 10.1016/0009-2541(92)90033-2

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Abstract

Few black shales contain concentrations of precious metals higher than average continental crust (i.e. ???5 ppb Au). Yet Au and Pt alloys have been reported from the Kupferschiefer in Poland. Moreover, thin sulfide beds in certain Chinese and Canadian shales contain several hundred ppb Au, Pd and Pt and average ???4% Mo and ???2.5% Ni in an association that is difficult to explain. Volcanic and non-volcanic exhalations, hydrothermal epigenesis involving either igneous or sedex fluids, biogenic processes and low-temperature secondary enrichment are among the possible factors involved in deriving Ni, PGE and Au for black shales and sulfide beds in black shales. Extraterrestrial sources have been invoked in some cases (e.g., the Cambrian of China). However, available data on abundances of PGE indicate relatively low values for Ir (<0.02-2 ppb) in comparison with amounts for other PGE (up to 700 ppb Pt and 1255 ppb Pd). These data and high contents for Mo are not consistent with extraterrestrial sources of metals for Chinese shales and Ni-Mo-sulfide beds. Data are less complete for the U.S. shales, but nevertheless are suggestive of earthly origins for PGE. ?? 1992.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Gold and platinum in shales with evidence against extraterrestrial sources of metals
Series title:
Chemical Geology
DOI:
10.1016/0009-2541(92)90033-2
Volume
99
Issue:
1-3
Year Published:
1992
Language:
English
Publisher:
Elsevier
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Chemical Geology
First page:
101
Last page:
114
Number of Pages:
14