TY - JOUR
T1 - Isotopic evidence for an anomalously low oceanic sulfate concentration following end-Permian mass extinction
AU - Luo, Genming
AU - Kump, Lee R.
AU - Wang, Yongbiao
AU - Tong, Jinnan
AU - Arthur, Michael A.
AU - Yang, Hao
AU - Huang, Junhua
AU - Yin, Hongfu
AU - Xie, Shucheng
N1 - Funding Information:
The authors would like to thank Prof. Chaoyong Hu, Dr. Xiaoyan Ruan and Shouzhi Hu for their assistance in the field. We are indebted to Prof. Tom Algeo and Ying Cui for discussion of P–Tr events, and Prof. Shuhai Xiao for constructive suggestions and critical comments on an earlier version of the manuscript. Master's students Xiao Bai, Lei He, Ze Zhang, Xia Wu and Huan Wang are also thanked for their help in the laboratory. This work was supported by the Chinese National Natural Science Foundation (grant nos. 40730209 and 40921062 ), the 973 program (grant no. 2011CB808800 ), the 111 project (grant no. B08030 ), the US National Science Foundation ( EAR 0807744 to LRK), and the US NASA Astrobiology Institute (grant no. NAA09DA76A ) to MAA and LRK.
PY - 2010/11/15
Y1 - 2010/11/15
N2 - The cataclysmic end-Permian mass extinction was immediately followed by a global expansion of microbial ecosystems, as demonstrated by widespread microbialite sequences (disaster facies) in shallow water settings. Here we present high-resolution carbonate carbon (δ13Ccarb) and carbonate-associated sulfate-sulfur isotope (δ34SCAS) records from the microbialite in the Cili Permian-Triassic (P-Tr) section in South China. A stepwise decline in δ13Ccarb begins in the underlying skeletal limestone, predating the main oceanic mass extinction and the first appearance of microbialite, and reaches its nadir in the upper part of the microbialite layer. The corresponding δ34SCAS, in the range of 17.4‰ to 27.4‰, is relatively stable in the underlying skeletal limestone, and increases gradually from 2m below the microbialite rising to a peak at the base of the microbialite. Two episodes of positive and negative shifts occurred within the microbialite layer, and exhibit a remarkable co-variance of sulfur and carbon isotope composition. The large amplitude of the variation in δ34SCAS, as high as 7‰ per 100kiloyears, suggests a small oceanic sulfate reservoir size at this time. Furthermore, the δ13Ccarb and δ34SCAS records co-vary without phase lag throughout the microbialite interval, implying a marine-driven C cycle in an anoxic ocean with anomalously low oceanic sulfate concentrations. On the basis of a non-steady-state box model, we argue that the oceanic sulfate concentration may have fallen to less than 15%, perhaps as low as 3%, of that in the modern oceans. Low oceanic sulfate concentration likely was the consequence of evaporite deposition and widespread anoxic/sulfidic conditions prior to the main mass extinction. By promoting methanogenesis and a build-up of atmospheric CH4 and CO2, low oceanic sulfate may have intensified global warming, exacerbating the inimical environmental conditions of the latest Permian.
AB - The cataclysmic end-Permian mass extinction was immediately followed by a global expansion of microbial ecosystems, as demonstrated by widespread microbialite sequences (disaster facies) in shallow water settings. Here we present high-resolution carbonate carbon (δ13Ccarb) and carbonate-associated sulfate-sulfur isotope (δ34SCAS) records from the microbialite in the Cili Permian-Triassic (P-Tr) section in South China. A stepwise decline in δ13Ccarb begins in the underlying skeletal limestone, predating the main oceanic mass extinction and the first appearance of microbialite, and reaches its nadir in the upper part of the microbialite layer. The corresponding δ34SCAS, in the range of 17.4‰ to 27.4‰, is relatively stable in the underlying skeletal limestone, and increases gradually from 2m below the microbialite rising to a peak at the base of the microbialite. Two episodes of positive and negative shifts occurred within the microbialite layer, and exhibit a remarkable co-variance of sulfur and carbon isotope composition. The large amplitude of the variation in δ34SCAS, as high as 7‰ per 100kiloyears, suggests a small oceanic sulfate reservoir size at this time. Furthermore, the δ13Ccarb and δ34SCAS records co-vary without phase lag throughout the microbialite interval, implying a marine-driven C cycle in an anoxic ocean with anomalously low oceanic sulfate concentrations. On the basis of a non-steady-state box model, we argue that the oceanic sulfate concentration may have fallen to less than 15%, perhaps as low as 3%, of that in the modern oceans. Low oceanic sulfate concentration likely was the consequence of evaporite deposition and widespread anoxic/sulfidic conditions prior to the main mass extinction. By promoting methanogenesis and a build-up of atmospheric CH4 and CO2, low oceanic sulfate may have intensified global warming, exacerbating the inimical environmental conditions of the latest Permian.
UR - http://www.scopus.com/inward/record.url?scp=78149497643&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=78149497643&partnerID=8YFLogxK
U2 - 10.1016/j.epsl.2010.09.041
DO - 10.1016/j.epsl.2010.09.041
M3 - Article
AN - SCOPUS:78149497643
SN - 0012-821X
VL - 300
SP - 101
EP - 111
JO - Earth and Planetary Science Letters
JF - Earth and Planetary Science Letters
IS - 1-2
ER -
