Abstract
Multiple sulfur isotope system is a powerful new tracer for atmospheric, volcanic, and biological influences on sulfur cycles in the anoxic early Earth. Here, we report high-precision quadruple sulfur isotope analyses (32S/33S/34S/36S) of barite, pyrite in barite, and sulfides in related hydrothermal and igneous rocks occurring in the ca. 3.5 Ga Dresser Formation, Western Australia. Our results indicate that observed isotopic variations are mainly controlled by mixing of mass-dependently (MD) and non-mass-dependently fractionated (non-MD) sulfur reservoirs. Based on the quadruple sulfur isotope systematics (δ34S-Δ33S-Δ36S) for these minerals, four end-member sulfur reservoirs have been recognized: (1) non-MD sulfate (δ34S = -5 ± 2‰; Δ33S = -3 ± 1‰); (2) MD sulfate (δ34S = +10 ± 3‰); (3) non-MD sulfur (δ34S > +6‰; Δ33S > +4‰); and (4) igneous MD sulfur (δ34S = Δ33S = 0‰). The first and third components show a clear non-MD signatures, thus probably represent sulfate and sulfur aerosol inputs. The MD sulfate component (2) is enriched in 34S (+10 ± 3‰) and may have originated from microbial and/or abiotic disproportionation of volcanic S or SO2. Our results reconfirm that the Dresser barites contain small amounts of pyrite depleted in 34S by 15-22‰ relative to the host barite. These barite-pyrite pairs exhibit a mass-dependent relationship of δ33S/δ34S with slope less than 0.512, which is consistent with that expected for microbial sulfate reduction and is significantly different from that of equilibrium fractionation (0.515). The barite-pyrite pairs also show up to 1‰ difference in Δ36S values and steep Δ36S/Δ33S slopes, which deviate from the main Archean array (Δ36S/Δ33S = -0.9) and are comparable to isotope effects exhibited by sulfate reducing microbes (Δ36S/Δ33S = -5 to -11). These new lines of evidence support the existence of sulfate reducers at ca. 3.5 Ga, whereas microbial sulfur disproportionation may have been more limited than recently suggested.
| Original language | English |
|---|---|
| Pages (from-to) | 5675-5691 |
| Number of pages | 17 |
| Journal | Geochimica et Cosmochimica Acta |
| Volume | 72 |
| Issue number | 23 |
| DOIs | |
| Publication status | Published - Dec 1 2008 |
| Externally published | Yes |
Fingerprint
ASJC Scopus subject areas
- Geochemistry and Petrology
Cite this
Quadruple sulfur isotope analysis of ca. 3.5 Ga Dresser Formation : New evidence for microbial sulfate reduction in the early Archean. / Ueno, Yuichiro; Ono, Shuhei; Rumble, Douglas; Maruyama, Shigenori.
In: Geochimica et Cosmochimica Acta, Vol. 72, No. 23, 01.12.2008, p. 5675-5691.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Quadruple sulfur isotope analysis of ca. 3.5 Ga Dresser Formation
T2 - New evidence for microbial sulfate reduction in the early Archean
AU - Ueno, Yuichiro
AU - Ono, Shuhei
AU - Rumble, Douglas
AU - Maruyama, Shigenori
PY - 2008/12/1
Y1 - 2008/12/1
N2 - Multiple sulfur isotope system is a powerful new tracer for atmospheric, volcanic, and biological influences on sulfur cycles in the anoxic early Earth. Here, we report high-precision quadruple sulfur isotope analyses (32S/33S/34S/36S) of barite, pyrite in barite, and sulfides in related hydrothermal and igneous rocks occurring in the ca. 3.5 Ga Dresser Formation, Western Australia. Our results indicate that observed isotopic variations are mainly controlled by mixing of mass-dependently (MD) and non-mass-dependently fractionated (non-MD) sulfur reservoirs. Based on the quadruple sulfur isotope systematics (δ34S-Δ33S-Δ36S) for these minerals, four end-member sulfur reservoirs have been recognized: (1) non-MD sulfate (δ34S = -5 ± 2‰; Δ33S = -3 ± 1‰); (2) MD sulfate (δ34S = +10 ± 3‰); (3) non-MD sulfur (δ34S > +6‰; Δ33S > +4‰); and (4) igneous MD sulfur (δ34S = Δ33S = 0‰). The first and third components show a clear non-MD signatures, thus probably represent sulfate and sulfur aerosol inputs. The MD sulfate component (2) is enriched in 34S (+10 ± 3‰) and may have originated from microbial and/or abiotic disproportionation of volcanic S or SO2. Our results reconfirm that the Dresser barites contain small amounts of pyrite depleted in 34S by 15-22‰ relative to the host barite. These barite-pyrite pairs exhibit a mass-dependent relationship of δ33S/δ34S with slope less than 0.512, which is consistent with that expected for microbial sulfate reduction and is significantly different from that of equilibrium fractionation (0.515). The barite-pyrite pairs also show up to 1‰ difference in Δ36S values and steep Δ36S/Δ33S slopes, which deviate from the main Archean array (Δ36S/Δ33S = -0.9) and are comparable to isotope effects exhibited by sulfate reducing microbes (Δ36S/Δ33S = -5 to -11). These new lines of evidence support the existence of sulfate reducers at ca. 3.5 Ga, whereas microbial sulfur disproportionation may have been more limited than recently suggested.
AB - Multiple sulfur isotope system is a powerful new tracer for atmospheric, volcanic, and biological influences on sulfur cycles in the anoxic early Earth. Here, we report high-precision quadruple sulfur isotope analyses (32S/33S/34S/36S) of barite, pyrite in barite, and sulfides in related hydrothermal and igneous rocks occurring in the ca. 3.5 Ga Dresser Formation, Western Australia. Our results indicate that observed isotopic variations are mainly controlled by mixing of mass-dependently (MD) and non-mass-dependently fractionated (non-MD) sulfur reservoirs. Based on the quadruple sulfur isotope systematics (δ34S-Δ33S-Δ36S) for these minerals, four end-member sulfur reservoirs have been recognized: (1) non-MD sulfate (δ34S = -5 ± 2‰; Δ33S = -3 ± 1‰); (2) MD sulfate (δ34S = +10 ± 3‰); (3) non-MD sulfur (δ34S > +6‰; Δ33S > +4‰); and (4) igneous MD sulfur (δ34S = Δ33S = 0‰). The first and third components show a clear non-MD signatures, thus probably represent sulfate and sulfur aerosol inputs. The MD sulfate component (2) is enriched in 34S (+10 ± 3‰) and may have originated from microbial and/or abiotic disproportionation of volcanic S or SO2. Our results reconfirm that the Dresser barites contain small amounts of pyrite depleted in 34S by 15-22‰ relative to the host barite. These barite-pyrite pairs exhibit a mass-dependent relationship of δ33S/δ34S with slope less than 0.512, which is consistent with that expected for microbial sulfate reduction and is significantly different from that of equilibrium fractionation (0.515). The barite-pyrite pairs also show up to 1‰ difference in Δ36S values and steep Δ36S/Δ33S slopes, which deviate from the main Archean array (Δ36S/Δ33S = -0.9) and are comparable to isotope effects exhibited by sulfate reducing microbes (Δ36S/Δ33S = -5 to -11). These new lines of evidence support the existence of sulfate reducers at ca. 3.5 Ga, whereas microbial sulfur disproportionation may have been more limited than recently suggested.
UR - http://www.scopus.com/inward/record.url?scp=55149084784&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=55149084784&partnerID=8YFLogxK
U2 - 10.1016/j.gca.2008.08.026
DO - 10.1016/j.gca.2008.08.026
M3 - Article
VL - 72
SP - 5675
EP - 5691
JO - Geochmica et Cosmochimica Acta
JF - Geochmica et Cosmochimica Acta
SN - 0016-7037
IS - 23
ER -