Calcimicrobial cap rocks from the basal Triassic units: western Taurus occurrences (SW Turkey)

Baud, Aymon; Richoz, Sylvain; Marcoux, Jean

doi:10.1016/j.crpv.2005.03.001

Cited by 107 publications

(68 citation statements)

References 24 publications

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“…According to the process envisaged, organic matter concentrated in anoxic stratified ocean bottom was subject to sulfate reduction under the effect of anaerobic bacteria, presumed to have given rise to a large reservoir of dissolved inorganic carbon (DIC) present as HCO 3 − , CO 3 2− , together with H 2 S. The DIC was upwelled to oxygen-enriched shallow sea and quickly degassed, resulting in extreme saturation of the carbonate content of the seawater so that calcification of microbial mats and the formation of PTBMs took place. This model was widely invoked in numerous studies (Lehrmann et al 2003;Baud et al 2005Baud et al , 2007Hips and Haas 2006;Pruss et al 2006;Kershaw et al 2007;Ezaki et al 2008;Kershaw et al 2009Kershaw et al , 2011Mary and Woods 2008;Mata and Bottjer 2011). Coupling between PTBMs occurrence and the negative excursion of carbon isotopes (Mu et al 2009) supported this hypothesis.…”

Section: Paleoenvironmental Significance Of the Ptbmssupporting

confidence: 52%

Permian–Triassic boundary microbialites (PTBMs) in southwest China: implications for paleoenvironment reconstruction

Tang

Kershaw

Liu

et al. 2016

Facies

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combination of increase in abundance and size of metazoan fossils upsection, together with the low TOC and TS contents, is evidence that the Yudongzi PTBMs developed in oxic seawater. We thus dispute the previous view, at least for the Chinese sequences, of low-oxygen seawater for microbialite growth, and question whether it is now appropriate to associate PTBMs with anoxic, harsh environments associated with the end-Permian extinction. Instead, we interpret those conditions as fully oxygenated.

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Section: Paleoenvironmental Significance Of the Ptbmssupporting

confidence: 52%

Permian–Triassic boundary microbialites (PTBMs) in southwest China: implications for paleoenvironment reconstruction

Tang

Kershaw

Liu

et al. 2016

Facies

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“…First, the synchronous deposition of microbialites and oolites across the global tropics within the H. parvus conodont zone (7,8) could reflect rapid carbonate deposition resulting from enhanced silicate and carbonate weathering in the aftermath of a CO 2 release event. The weathering hypothesis can explain why synchronous, widespread deposition of these facies is confined to the earliest Triassic, despite the persistence of ocean anoxia (55) and skeleton-poor carbonate sediments (34) through much of Early Triassic time.…”

Section: Discussionmentioning

confidence: 99%

“…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.

216

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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“…In particular, Turkey (Baud et al, 2005) and Iran (Heydari et al 2000) have important microbial deposits, located in central Tethyan positions during the PTB interval (Fig. 6).…”

Section: C Carbon Isotopes Microbialites and Tethys Oceanmentioning

confidence: 99%

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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Calcimicrobial cap rocks from the basal Triassic units: western Taurus occurrences (SW Turkey)

Cited by 107 publications

References 24 publications

Permian–Triassic boundary microbialites (PTBMs) in southwest China: implications for paleoenvironment reconstruction

Permian–Triassic boundary microbialites (PTBMs) in southwest China: implications for paleoenvironment reconstruction

Calcium isotope constraints on the end-Permian mass extinction

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

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