In:
Science, American Association for the Advancement of Science (AAAS), Vol. 346, No. 6210 ( 2014-11-07), p. 742-744
Abstract:
The minor extent of sulfur isotope fractionation preserved in many Neoarchean sedimentary successions suggests that sulfate-reducing microorganisms played an insignificant role in ancient marine environments, despite evidence that these organisms evolved much earlier. We present bulk, microdrilled, and ion probe sulfur isotope data from carbonate-associated pyrite in the ~2.5-billion-year-old Batatal Formation of Brazil, revealing large mass-dependent fractionations (approaching 50 per mil) associated with microbial sulfate reduction, as well as consistently negative Δ 33 S values (~ –2 per mil) indicative of atmospheric photochemical reactions. Persistent 33 S depletion through ~60 meters of shallow marine carbonate implies long-term stability of seawater sulfate abundance and isotope composition. In contrast, a negative Δ 33 S excursion in lower Batatal strata indicates a response time of ~40,000 to 150,000 years, suggesting Neoarchean sulfate concentrations between ~1 and 10 μM.
Type of Medium:
Online Resource
ISSN:
0036-8075
,
1095-9203
DOI:
10.1126/science.1256211
Language:
English
Publisher:
American Association for the Advancement of Science (AAAS)
Publication Date:
2014
detail.hit.zdb_id:
128410-1
detail.hit.zdb_id:
2066996-3
SSG:
11
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