Isotopic evidence for anoxic pyrite oxidation and stimulation of bacterial sulphate reduction in marine sediments

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doi: 10.1144/jgs.157.4.711
Author(s): Bottrell, S. H.; Parkes, R. J.; Cragg, B. A.; Raiswell, R.
Author Affiliation(s): Primary:
University of Leeds, School of Earth Sciences, Leeds, United Kingdom
University of Bristol, Department of Earth Sciences, Bristol, United Kingdom
Volume Title: Journal of the Geological Society of London
Source: Journal of the Geological Society of London, Vol.157(Part 4), p.711-714. Publisher: Geological Society of London, London, United Kingdom. ISSN: 0016-7649 CODEN: JGSLAS
Note: In English. 26 refs.; illus., incl. sketch map
Summary: Pore-water sulphate concentrations show marked increases at depths >50 m at ODP sites 888 and 890/889 from the Cascadia Margin accretionary wedge. In the uppermost 10 m sulphate concentrations decrease with depth and sulphate δ34S and δ18O increase as sulphate is removed by bacterial sulphate reduction. Isotopic data show that sulphate formed below 50 m results from oxidation of early diagenetic pyrite and that oxygen in the sulphate molecules is derived from pore water. Fe3+ in the sediment is the probable oxidizing agent. The increased sulphate concentrations stimulate bacterial sulphate reduction at depths of 70-250 m and are thus important in sustaining deep bacterial activity.
Year of Publication: 2000
Research Program: ODP Ocean Drilling Program
Key Words: 02 Geochemistry; Anaerobic environment; Bacteria; Cascadia Basin; Cores; Diagenesis; East Pacific; Isotope ratios; Isotopes; Leg 146; Marine sediments; North Pacific; Northeast Pacific; O-18/O-16; ODP Site 888; ODP Site 889; ODP Site 890; Ocean Drilling Program; Oxidation; Oxygen; Pacific Ocean; Pore water; Pyrite; Reduction; S-34/S-32; Sediments; Stable isotopes; Sulfides; Sulfur
Coordinates: N480959 N481001 W1263943 W1263948
N484151 N484159 W1265206 W1265223
N483945 N483945 W1265253 W1265253
Record ID: 2000054427
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from The Geological Society, London, London, United Kingdom