Abstract
Mass-independent fractionation (MIF) of sulfur isotopes has been reported in sediments of Archean and Early Proterozoic Age (>2.3 Ga) but not in younger rocks. The only fractionation mechanism that is consistent with the data on all four sulfur isotopes involves atmospheric photochemical reactions such as SO 2 photolysis. We have used a one-dimensional photochemical model to investigate how the isotopic fractionation produced during SO 2 photolysis would have been transferred to other gaseous and particulate sulfur-bearing species in both low-O 2 and high-O 2 atmospheres. We show that in atmospheres with O 2 concentrations <10 -5 times the present atmospheric level (PAL), sulfur would have been removed from the atmosphere in a variety of different oxidation states, each of which would have had its own distinct isotopic signature. By contrast, in atmospheres with O 2 concentrations ≥10 -5 PAL, all sulfur-bearing species would have passed through the oceanic sulfate reservoir before being incorporated into sediments, so any signature of MIF would have been lost. We conclude that the atmospheric O 2 concentration must have been <10 -5 PAL prior to 2.3 Ga.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 27-41 |
| Number of pages | 15 |
| Journal | Astrobiology |
| Volume | 2 |
| Issue number | 1 |
| DOIs | |
| State | Published - Mar 1 2002 |
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All Science Journal Classification (ASJC) codes
- Agricultural and Biological Sciences (miscellaneous)
- Space and Planetary Science
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Mass-independent fractionation of sulfur isotopes in archean sediments : Strong evidence for an anoxic archean atmosphere. / Pavlov, A. A.; Kasting, J. F.
In: Astrobiology, Vol. 2, No. 1, 01.03.2002, p. 27-41.Research output: Contribution to journal › Article
TY - JOUR
T1 - Mass-independent fractionation of sulfur isotopes in archean sediments
T2 - Strong evidence for an anoxic archean atmosphere
AU - Pavlov, A. A.
AU - Kasting, J. F.
PY - 2002/3/1
Y1 - 2002/3/1
N2 - Mass-independent fractionation (MIF) of sulfur isotopes has been reported in sediments of Archean and Early Proterozoic Age (>2.3 Ga) but not in younger rocks. The only fractionation mechanism that is consistent with the data on all four sulfur isotopes involves atmospheric photochemical reactions such as SO 2 photolysis. We have used a one-dimensional photochemical model to investigate how the isotopic fractionation produced during SO 2 photolysis would have been transferred to other gaseous and particulate sulfur-bearing species in both low-O 2 and high-O 2 atmospheres. We show that in atmospheres with O 2 concentrations <10 -5 times the present atmospheric level (PAL), sulfur would have been removed from the atmosphere in a variety of different oxidation states, each of which would have had its own distinct isotopic signature. By contrast, in atmospheres with O 2 concentrations ≥10 -5 PAL, all sulfur-bearing species would have passed through the oceanic sulfate reservoir before being incorporated into sediments, so any signature of MIF would have been lost. We conclude that the atmospheric O 2 concentration must have been <10 -5 PAL prior to 2.3 Ga.
AB - Mass-independent fractionation (MIF) of sulfur isotopes has been reported in sediments of Archean and Early Proterozoic Age (>2.3 Ga) but not in younger rocks. The only fractionation mechanism that is consistent with the data on all four sulfur isotopes involves atmospheric photochemical reactions such as SO 2 photolysis. We have used a one-dimensional photochemical model to investigate how the isotopic fractionation produced during SO 2 photolysis would have been transferred to other gaseous and particulate sulfur-bearing species in both low-O 2 and high-O 2 atmospheres. We show that in atmospheres with O 2 concentrations <10 -5 times the present atmospheric level (PAL), sulfur would have been removed from the atmosphere in a variety of different oxidation states, each of which would have had its own distinct isotopic signature. By contrast, in atmospheres with O 2 concentrations ≥10 -5 PAL, all sulfur-bearing species would have passed through the oceanic sulfate reservoir before being incorporated into sediments, so any signature of MIF would have been lost. We conclude that the atmospheric O 2 concentration must have been <10 -5 PAL prior to 2.3 Ga.
UR - http://www.scopus.com/inward/record.url?scp=0036490498&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0036490498&partnerID=8YFLogxK
U2 - 10.1089/153110702753621321
DO - 10.1089/153110702753621321
M3 - Article
C2 - 12449853
AN - SCOPUS:0036490498
VL - 2
SP - 27
EP - 41
JO - Astrobiology
JF - Astrobiology
SN - 1531-1074
IS - 1
ER -