?Microbialites in the Permian-Triassic boundary interval in central China: Structure, age and distribution

Kershaw, Steve; Guo, Lu; Swift, A.D.; Fan, Junxuan

doi:10.1007/bf02667707

Cited by 108 publications

(76 citation statements)

References 22 publications

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“…3C are evidence that sediment enclosing the microbialite structure was contemporaneous with the growth of the microbialite branches. These results support the suggestion by Kershaw et al (1999Kershaw et al ( , 2002 that microbialite branches protruded a short distance above the enclosing sediment, keeping pace with sedimentation as the microbialite branches grew. …”

Section: B Carbon Isotopes Marine Oxygenation and Earliest Triassisupporting

confidence: 90%

“…4 & 5), including Hindeodus parvus, the first Triassic conodont. Kershaw et al (2002) also found H. parvus near the top of the microbialite in nearby locations. However, Liu et al (2006) reported H. parvus at the base of the microbialite in other sites; it is possible that the base of the microbialite, sharply overlying the Changhsing Formation, is indeed the PTB in this site, but this requires further precise stratigraphic work to confirm.…”

Section: Locality Geological Setting and Methodsmentioning

confidence: 82%

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High-resolution carbon isotope changes in the Permian–Triassic boundary interval, Chongqing, South China; implications for control and growth of earliest Triassic microbialites

Kershaw

et al. 2009

Journal of Asian Earth Sciences

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High-resolution δ 13 C CARB analysis of the Permian-Triassic boundary (PTB) interval at the Laolongdong section, Beibei, near the city of Chongqing, south China, encompasses the latest Permian and earliest Triassic major facies changes in the South China Block (SCB). Microbialites form a distinctive unit in the lowermost 190 cm above the top of the Changhsing Formation (latest Permian) at Laolongdong, comparable to a range of earliest Triassic sites in low latitudes in the Tethyan area. The data show that declining values of δ 13 C CARB , well-known globally, began at the base of the microbialite. High positive values (+3-4 ppt) of δ 13 C CARB in the Late Permian are interpreted to indicate storage of 12 C in the deep waters of a stratified ocean, that was released during ocean overturn in the earliest Triassic, contributing to the distinctive fall in isotope values; this interpretation has been stated by other authors and is followed here. The δ 13 C CARB curve shows fluctuations within the microbialite unit, which are not reflected in the microbialite structure. Comparisons between microbialite branches and adjacent micritic sediment show little difference in δ 13 C CARB , demonstrating that the microbialite grew in equilibrium with surrounding seawater. The Early Triassic microbialites are interpreted to be a response to upwelling of bicarbonate-rich poorly-oxygenated water in low latitudes of Tethys ocean, consistent with current ocean models for the PTB interval. However, the decline of δ 13 C CARB may be due to a combination of processes, including productivity collapse resulting from mass extinction, return of deep water to ocean surface,

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Section: B Carbon Isotopes Marine Oxygenation and Earliest Triassisupporting

confidence: 90%

Section: Locality Geological Setting and Methodsmentioning

confidence: 82%

High-resolution carbon isotope changes in the Permian–Triassic boundary interval, Chongqing, South China; implications for control and growth of earliest Triassic microbialites

Kershaw

et al. 2009

Journal of Asian Earth Sciences

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“…The Zagros PTB section is significant also in terms of the occurrence of organosedimentary crusts that have been reported from the other PTB sections elsewhere (Sano and Nakashima., 1997;Lehrmann, 1999;Kershaw et al, 1999Kershaw et al, , 2002Wignall and Twitchett, 2002;Ezaki et al, 2003;Hips and Haas, 2006;Pruss et al, 2006). These have been generally described as microbialites that were deposits formed by a result of a benthic microbial community (Brune and Moore, 1987).…”

Section: Introductionmentioning

confidence: 99%

Isotopic chemostratigraphy of the microbialite-bearing Permian–Triassic boundary section in the Zagros Mountains, Iran

et al. 2007

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“…Microbialites and oolites overlie diverse, fossiliferous limestones of the latest Permian age in carbonate strata deposited across the tropical Tethys (1)(2)(3)(4)(5)(6)(7)(8) and in the Panthalassa Ocean (8,9) (Fig. S1).…”

mentioning

confidence: 99%

Calcium isotope constraints on the end-Permian mass extinction

Payne

Turchyn

Paytan

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

217

164

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The end-Permian mass extinction horizon is marked by an abrupt shift in style of carbonate sedimentation and a negative excursion in the carbon isotope (δ 13 C) composition of carbonate minerals. Several extinction scenarios consistent with these observations have been put forward. Secular variation in the calcium isotope (δ 44∕40 Ca) composition of marine sediments provides a tool for distinguishing among these possibilities and thereby constraining the causes of mass extinction. Here we report δ 44∕40 Ca across the Permian-Triassic boundary from marine limestone in south China. The δ 44∕40 Ca exhibits a transient negative excursion of ∼0.3‰ over a few hundred thousand years or less, which we interpret to reflect a change in the global δ 44∕40 Ca composition of seawater. CO 2 -driven ocean acidification best explains the coincidence of the δ 44∕40 Ca excursion with negative excursions in the δ 13 C of carbonates and organic matter and the preferential extinction of heavily calcified marine animals. Calcium isotope constraints on carbon cycle calculations suggest that the average δ 13 C of CO 2 released was heavier than −28‰ and more likely near −15‰; these values indicate a source containing substantial amounts of mantle-or carbonatederived carbon. Collectively, the results point toward Siberian Trap volcanism as the trigger of mass extinction.

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?Microbialites in the Permian-Triassic boundary interval in central China: Structure, age and distribution

Cited by 108 publications

References 22 publications

High-resolution carbon isotope changes in the Permian–Triassic boundary interval, Chongqing, South China; implications for control and growth of earliest Triassic microbialites

High-resolution carbon isotope changes in the Permian–Triassic boundary interval, Chongqing, South China; implications for control and growth of earliest Triassic microbialites

Isotopic chemostratigraphy of the microbialite-bearing Permian–Triassic boundary section in the Zagros Mountains, Iran

Calcium isotope constraints on the end-Permian mass extinction

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