Mineralogy and sulphur isotope characteristics of a massive sulphide boulder, Galapagos Rift, 85°55′W
- 1 January 1995
- journal article
- Published by Geological Society of London in Geological Society, London, Special Publications
- Vol. 87 (1) , 207-222
- https://doi.org/10.1144/gsl.sp.1995.087.01.17
Abstract
The submarine hydrothermal sulphide deposits of the Galapagos Rift are characterized by being exceptionally Cu-rich. Fe- and Cu-Fe sulphides are extremely heterogeneous, display granular textures and evidence of open space growth. Core was examined from a 1.5 m diameter massive sulphide boulder collected by TV grab on the GARIMAS II cruise. The main growth stage is dominated by pyrite and chalcopyrite, forming granular aggregates from 5 cm. These sulphides have δ 34 S from +2.7 to + 5.5‰. The Fe-Cu sulphides are modified by minor seawater oxidation and a late stage marcasite-sphalerite-galena-barite assemblage. δ 34 S varies along the core in a systematic manner and there appears to be an isotopically heavy deviation from the modal +3.9‰. This is related to particular zones and suggests a second, isotopically distinct S source, which is interpreted to be a hydrothermal diagenetic solution derived from a shallow seawater-hydrothermal circulation system.This publication has 28 references indexed in Scilit:
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