Abstract
The distribution of gold in black-shale associations in various parts of the crust is non-uniform, but in most regions, the contents of the metal in carbonaceous shales are elevated by factors of 5-10: 6.7-65 ppb. A general estimate of average Au contents is given: 14.7 ppb for carbonaceous rocks and 2.0 ppb for clay shales. The main concentrator mineral is pyrite, which contains 27-1360 ppb. The pyrite content in sulphidized horizons in black shale ranges from 58-2000 ppm up to 2-6% by volume. The gold in the carbonaceous material often constitutes 18-60% of the total gold content of the rock. Aureoles of elevated gold content in black-shale horizons are controlled by jointing zones and are related to hydrothermal and metasomatic processes causing the redistribution and influx of heavy-metal components with plutonic solutions 032(KaAu = or > 10-300). Diagenesis also tends to raise Au contents in terrigenous beds. (Author's abstract)-A.W.H.Polytechnical Inst., Tomsk, USSR.
Original language | English |
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Pages (from-to) | 114-124 |
Number of pages | 11 |
Journal | Geochemistry International |
Volume | 23 |
Issue number | 5 |
Publication status | Published - 1986 |
ASJC Scopus subject areas
- Geochemistry and Petrology
- Geophysics