Micro-scale quadruple sulfur isotope analysis of pyrite from the ~3480Ma Dresser Formation: New insights into sulfur cycling on the early Earth

David Wacey, N. Noffke, John Cliff, Mark Barley, J. Farquhar

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

© 2014 Elsevier B.V. We report in situ quadruple sulfur isotope analysis (32S, 33S, 34S and 36S) of a pyritized microbial mat from the ~3480Ma Dresser Formation, Pilbara Craton, Western Australia. These data yield positive δ34S and δ33S, indicative of sulfur sourced from a pool with similar character as the putative atmospheric elemental sulfur channel of Pavlov and Kasting (2002). Contrary to previous data from the Dresser Formation, however, this pyrite is heavily depleted in 36S with a δ36S/δ33S slope of c. -3.6, much steeper than slopes typically seen in other early Archean rock successions (δ36S/δ33S≈-1) which suggests either a different atmospheric signature for deposited S or a different pool altogether. Significant micro-scale isotopic heterogeneity is observed within the microbial mat (δ34S=+1.6‰ to +6.7‰ δ33S=+0.4‰ to +2.6‰ δ36S=-3.1‰ to -8.1‰), implying a role for microbial S metabolism. While metabolic S cycling has been shown to shift δ36S to lower values, microbial metabolization of S does not appear sufficient to account for the full range of δ36S.We conclude that the isotopic composition of the pyrite was controlled by the relative proportions of mass independently fractionated (MIF) S0 and sulfate-derived sulfur incorporated into polysulfide pyrite precursors during reactions in the microbial mat. The dominance of the MIF-S0 isotopic signature (+δ34S, +δ33S, -δ36S) indicates that contributions from the sulfate-derived sulfur pool were relatively small, consistent with low concentrations of sulfate in Archean seawater, and that contributions from a non-sulfate pool were significant. Micro-scale isotopic heterogeneity in the pyrite points to mixing between the two sulfur pools in selected micro-environments within the microbial mat. The particularly negative δ36S observed here reveals a 3480Ma sulfur reservoir with novel δ36S/δ33S chemistry whose significance now requires further investigation.
Original languageEnglish
Pages (from-to)24-35
Number of pages12
JournalPrecambrian Research
Volume258
DOIs
Publication statusPublished - Mar 2015

Fingerprint

Sulfur Isotopes
early Earth
sulfur isotope
Sulfur
pyrite
microbial mat
Earth (planet)
sulfur
Sulfates
sulfate
Archean
Seawater
Metabolism
analysis
craton
isotopic composition
metabolism
Rocks
seawater

Cite this

@article{e0e8e28a448c490aa5e7bb3bdfb9b532,
title = "Micro-scale quadruple sulfur isotope analysis of pyrite from the ~3480Ma Dresser Formation: New insights into sulfur cycling on the early Earth",
abstract = "{\circledC} 2014 Elsevier B.V. We report in situ quadruple sulfur isotope analysis (32S, 33S, 34S and 36S) of a pyritized microbial mat from the ~3480Ma Dresser Formation, Pilbara Craton, Western Australia. These data yield positive δ34S and δ33S, indicative of sulfur sourced from a pool with similar character as the putative atmospheric elemental sulfur channel of Pavlov and Kasting (2002). Contrary to previous data from the Dresser Formation, however, this pyrite is heavily depleted in 36S with a δ36S/δ33S slope of c. -3.6, much steeper than slopes typically seen in other early Archean rock successions (δ36S/δ33S≈-1) which suggests either a different atmospheric signature for deposited S or a different pool altogether. Significant micro-scale isotopic heterogeneity is observed within the microbial mat (δ34S=+1.6‰ to +6.7‰ δ33S=+0.4‰ to +2.6‰ δ36S=-3.1‰ to -8.1‰), implying a role for microbial S metabolism. While metabolic S cycling has been shown to shift δ36S to lower values, microbial metabolization of S does not appear sufficient to account for the full range of δ36S.We conclude that the isotopic composition of the pyrite was controlled by the relative proportions of mass independently fractionated (MIF) S0 and sulfate-derived sulfur incorporated into polysulfide pyrite precursors during reactions in the microbial mat. The dominance of the MIF-S0 isotopic signature (+δ34S, +δ33S, -δ36S) indicates that contributions from the sulfate-derived sulfur pool were relatively small, consistent with low concentrations of sulfate in Archean seawater, and that contributions from a non-sulfate pool were significant. Micro-scale isotopic heterogeneity in the pyrite points to mixing between the two sulfur pools in selected micro-environments within the microbial mat. The particularly negative δ36S observed here reveals a 3480Ma sulfur reservoir with novel δ36S/δ33S chemistry whose significance now requires further investigation.",
author = "David Wacey and N. Noffke and John Cliff and Mark Barley and J. Farquhar",
year = "2015",
month = "3",
doi = "10.1016/j.precamres.2014.12.012",
language = "English",
volume = "258",
pages = "24--35",
journal = "Precambrian Research",
issn = "0301-9268",
publisher = "Pergamon",

}

Micro-scale quadruple sulfur isotope analysis of pyrite from the ~3480Ma Dresser Formation: New insights into sulfur cycling on the early Earth. / Wacey, David; Noffke, N.; Cliff, John; Barley, Mark; Farquhar, J.

In: Precambrian Research, Vol. 258, 03.2015, p. 24-35.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Micro-scale quadruple sulfur isotope analysis of pyrite from the ~3480Ma Dresser Formation: New insights into sulfur cycling on the early Earth

AU - Wacey, David

AU - Noffke, N.

AU - Cliff, John

AU - Barley, Mark

AU - Farquhar, J.

PY - 2015/3

Y1 - 2015/3

N2 - © 2014 Elsevier B.V. We report in situ quadruple sulfur isotope analysis (32S, 33S, 34S and 36S) of a pyritized microbial mat from the ~3480Ma Dresser Formation, Pilbara Craton, Western Australia. These data yield positive δ34S and δ33S, indicative of sulfur sourced from a pool with similar character as the putative atmospheric elemental sulfur channel of Pavlov and Kasting (2002). Contrary to previous data from the Dresser Formation, however, this pyrite is heavily depleted in 36S with a δ36S/δ33S slope of c. -3.6, much steeper than slopes typically seen in other early Archean rock successions (δ36S/δ33S≈-1) which suggests either a different atmospheric signature for deposited S or a different pool altogether. Significant micro-scale isotopic heterogeneity is observed within the microbial mat (δ34S=+1.6‰ to +6.7‰ δ33S=+0.4‰ to +2.6‰ δ36S=-3.1‰ to -8.1‰), implying a role for microbial S metabolism. While metabolic S cycling has been shown to shift δ36S to lower values, microbial metabolization of S does not appear sufficient to account for the full range of δ36S.We conclude that the isotopic composition of the pyrite was controlled by the relative proportions of mass independently fractionated (MIF) S0 and sulfate-derived sulfur incorporated into polysulfide pyrite precursors during reactions in the microbial mat. The dominance of the MIF-S0 isotopic signature (+δ34S, +δ33S, -δ36S) indicates that contributions from the sulfate-derived sulfur pool were relatively small, consistent with low concentrations of sulfate in Archean seawater, and that contributions from a non-sulfate pool were significant. Micro-scale isotopic heterogeneity in the pyrite points to mixing between the two sulfur pools in selected micro-environments within the microbial mat. The particularly negative δ36S observed here reveals a 3480Ma sulfur reservoir with novel δ36S/δ33S chemistry whose significance now requires further investigation.

AB - © 2014 Elsevier B.V. We report in situ quadruple sulfur isotope analysis (32S, 33S, 34S and 36S) of a pyritized microbial mat from the ~3480Ma Dresser Formation, Pilbara Craton, Western Australia. These data yield positive δ34S and δ33S, indicative of sulfur sourced from a pool with similar character as the putative atmospheric elemental sulfur channel of Pavlov and Kasting (2002). Contrary to previous data from the Dresser Formation, however, this pyrite is heavily depleted in 36S with a δ36S/δ33S slope of c. -3.6, much steeper than slopes typically seen in other early Archean rock successions (δ36S/δ33S≈-1) which suggests either a different atmospheric signature for deposited S or a different pool altogether. Significant micro-scale isotopic heterogeneity is observed within the microbial mat (δ34S=+1.6‰ to +6.7‰ δ33S=+0.4‰ to +2.6‰ δ36S=-3.1‰ to -8.1‰), implying a role for microbial S metabolism. While metabolic S cycling has been shown to shift δ36S to lower values, microbial metabolization of S does not appear sufficient to account for the full range of δ36S.We conclude that the isotopic composition of the pyrite was controlled by the relative proportions of mass independently fractionated (MIF) S0 and sulfate-derived sulfur incorporated into polysulfide pyrite precursors during reactions in the microbial mat. The dominance of the MIF-S0 isotopic signature (+δ34S, +δ33S, -δ36S) indicates that contributions from the sulfate-derived sulfur pool were relatively small, consistent with low concentrations of sulfate in Archean seawater, and that contributions from a non-sulfate pool were significant. Micro-scale isotopic heterogeneity in the pyrite points to mixing between the two sulfur pools in selected micro-environments within the microbial mat. The particularly negative δ36S observed here reveals a 3480Ma sulfur reservoir with novel δ36S/δ33S chemistry whose significance now requires further investigation.

U2 - 10.1016/j.precamres.2014.12.012

DO - 10.1016/j.precamres.2014.12.012

M3 - Article

VL - 258

SP - 24

EP - 35

JO - Precambrian Research

JF - Precambrian Research

SN - 0301-9268

ER -