Sulfide oxidation affects the preservation of sulfur isotope signals

The accumulation of oxygen in Earth's atmosphere and oceans in the late Archean had profound implications for the planet's biogeochemical evolution. Oxygen impacts sulfur cycling through the oxidation of sulfide minerals and the production of sulfate for microbial sulfate reduction (MSR)....

Full description

Saved in:
Bibliographic Details
Published in:Geology (Boulder) 2019-08, Vol.47 (8), p.739-743
Main Authors: Findlay, Alyssa J, Boyko, Valeria, Pellerin, André, Avetisyan, Khoren, Guo Qingjun, Guo Qingjun, Yang Xi, Yang Xi, Kamyshny, Alexey
Format: Article
Language:English
Subjects:
Aha Reservoir
Archean
Asia
Biogeochemistry
Biological activity
chemical fractionation
Chemical reactions
China
Cycles
Earth
Earth atmosphere
Evolution
Far East
geochemical cycle
geochemistry
Geology
Guizhou China
hydrochemistry
isotope ratios
Isotopes
lacustrine environment
lake sediments
Lakes
Microorganisms
Minerals
modern analogs
Neoarchean
Oceans
Organic chemistry
Oxidation
Oxygen
Planetary evolution
Precambrian
Preservation
pyrite
Reduction
S-34/S-32
Sediments
stable isotopes
sulfate ion
Sulfate reduction
Sulfates
Sulfides
Sulfur
sulfur cycle
Sulfur isotopes
Sulphate reduction
Sulphides
Sulphur
Water circulation
Water column
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The accumulation of oxygen in Earth's atmosphere and oceans in the late Archean had profound implications for the planet's biogeochemical evolution. Oxygen impacts sulfur cycling through the oxidation of sulfide minerals and the production of sulfate for microbial sulfate reduction (MSR). The isotopic signature of sulfur species preserved in the geologic record is affected by the prevailing biological and chemical processes and can therefore be used to constrain past oxygen and sulfate concentrations. Here, in a study of a late Archean analogue, we find that the sulfur isotopic signature in the water column of a seasonally stratified lake in southern China is influenced by MSR, whereas model results indicate that the isotopic signature of the underlying sediments can be best explained by concurrent sulfate reduction and sulfide oxidation. These data demonstrate that small apparent sulfur isotope fractionations (#2d34Ssulfate-AVS = 4.2ppm-1.5ppm; AVS-acid volatile sulfides) can be caused by dynamic sulfur cycling at millimolar sulfate concentrations. This is in contrast to current interpretations of the isotopic record and indicates that small fractionations do not necessarily indicate very low sulfate or oxygen.
ISSN:0091-7613
1943-2682
DOI:10.1130/G46153.1