Ocean's response to a changing climate: Clues from variations in carbonate mineralogy across the Permian–Triassic boundary of the Shareza Section, Iran

Heydari, Ezat; Arzani, Nasser; Safaei, Mohammad; Hassanzadeh, Jamshid

doi:10.1016/j.gloplacha.2012.12.013

Cited by 24 publications

(21 citation statements)

References 51 publications

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“…Moreover, our model outcome predicts δ 13 C variation driven solely by small biologically steered mineral contributions (f dia and/or f auth = 0.2; Fig. 6), whereas the recorded δ 13 C fluctuations are up to 10 times higher in amplitude than otherwise predicted for thermodynamically driven mineralspecific isotope compositional offsets (Brand et al, 2012b;Heydari et al, 2013). Note also that the mineral-specific isotope offset would require bulk-rock samples to display effectively complete (100 %) mineral compositional changes to a pure carbonate polymorph composition.…”

Section: Stochastic Carbon Isotope Signatures Of the Permian-triassicmentioning

confidence: 68%

“…Systematically 12 C-depleted bulk rock relative to brachiopod calcite (Schobben et al, 2016) further counters the notion of a variable predominance of an aragonite precursor for Permian carbonate rock (Brand et al, 2012b;Heydari et al, 2013). Nonetheless, secondary calcite and dolomite additions might be a causal factor behind observed δ 13 C variability.…”

Section: Stochastic Carbon Isotope Signatures Of the Permian-triassicmentioning

confidence: 77%

“…Subaerial exposure and projected trajectories of bulk-carbonate stabilization under the influence of meteoric fluids and high water-rock ratios might be invoked to explain this disparity (Heydari et al, 2001;Li and Jones, 2017). Other studies have pointed to stratigraphic variations in predominant mineral rock composition as a source of δ 13 C carb modulations, citing the mineral-specific isotope offset between aragonite, dolomite and low-Mg calcite (Brand et al, 2012b;Heydari et al, 2013;Schobben et al, 2016;Li and Jones, 2017).…”

Section: Stochastic Carbon Isotope Signatures Of the Permian-triassicmentioning

confidence: 99%

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Latest Permian carbonate carbon isotope variability traces heterogeneous organic carbon accumulation and authigenic carbonate formation

et al. 2017

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Abstract. Bulk-carbonate carbon isotope ratios are a widely applied proxy for investigating the ancient biogeochemical carbon cycle. Temporal carbon isotope trends serve as a prime stratigraphic tool, with the inherent assumption that bulk micritic carbonate rock is a faithful geochemical recorder of the isotopic composition of seawater dissolved inorganic carbon. However, bulk-carbonate rock is also prone to incorporate diagenetic signals. The aim of the present study is to disentangle primary trends from diagenetic signals in carbon isotope records which traverse the Permian-Triassic boundary in the marine carbonate-bearing sequences of Iran and South China. By pooling newly produced and published carbon isotope data, we confirm that a global first-order trend towards depleted values exists. However, a large amount of scatter is superimposed on this geochemical record. In addition, we observe a temporal trend in the amplitude of this residual δ 13 C variability, which is reproducible for the two studied regions. We suggest that (sub-)sea-floor microbial communities and their control on calcite nucleation and ambient porewater dissolved inorganic carbon δ 13 C pose a viable mechanism to induce bulk-rock δ 13 C variability. Numerical model calculations highlight that early diagenetic carbonate rock stabilization and linked carbon isotope alteration can be controlled by organic matter supply and subsequent microbial remineralization. A major biotic decline among Late Permian bottom-dwelling organisms facilitated a spatial increase in heterogeneous organic carbon accumulation. Combined with low marine sulfate, this resulted in varying degrees of carbon isotope overprinting. A simulated time series suggests that a 50 % increase in the spatial scatter of organic carbon relative to the average, in addition to an imposed increase in the likelihood of sampling cements formed by microbial calcite nucleation to 1 out of 10 samples, is sufficient to induce the observed signal of carbon isotope variability. These findings put constraints on the application of Permian-Triassic carbon isotope chemostratigraphy based on whole-rock samples, which appears less refined than classical biozonation dating schemes. On the other hand, this signal of increased carbon isotope variability concurrent with the largest mass extinction of the Phanerozoic may proPublished by Copernicus Publications on behalf of the European Geosciences Union.

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Section: Stochastic Carbon Isotope Signatures Of the Permian-triassicmentioning

confidence: 68%

Section: Stochastic Carbon Isotope Signatures Of the Permian-triassicmentioning

confidence: 77%

Section: Stochastic Carbon Isotope Signatures Of the Permian-triassicmentioning

confidence: 99%

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Latest Permian carbonate carbon isotope variability traces heterogeneous organic carbon accumulation and authigenic carbonate formation

et al. 2017

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“…Our new data are complemented by published bulk-carbonate δ 13 C data from multiple P-Tr localities in Central Iran (Abadeh (Heydari et al, 2000;Korte et al, 2004a;Horacek et al, 2007;Korte et al, 2010;Liu et al, 2013), Shahreza (Korte et al, 2004b;Heydari et al, 2008;Richoz et al, 2010) and north-western Iran (Ali Bashi mountains and Zal; Baud et al, 1989;Korte et al, 2004c;Kakuwa and Matsumoto, 2006;Horacek et al, 2007;Richoz et al, 2010;Schobben et al, 2016). For a more global perspective and a comparative approach, we additionally extracted published data from the P-Tr Global Boundary Stratotype Section and Point (GSSP) at Meishan, China (Baud et al, 1989;Chen et al, 1991;Xu and Yan, 1993;Hoffman et al, 1998;Jin et al, 2000;Cao et al, 2002;Gruszczyński et al, 2003;Zuo et al, 2006;Kaiho et al, 2006;Huang et al, 2007;Riccardi et al, 2007;Xie et al, 2007). Data were extracted from tables and supplementary files or provided by the authors and where necessary read from figures with the open-source software xyscan (Ullrich, 2016).…”

Section: Complementary Data Collectionmentioning

confidence: 99%

“…Meishan (Chen et al, 1991) Meishan (Hoffman et al, 1998) Meishan (Xu & Yan 1993) Meishan (Zuo et al, 2006) Meishan A (Kaiho et al, 2006) Meishan B Meishan B (Jin et al, 2000) Meishan B (Xie et al, 2007) Meishan D (Baud et al, 1989) Meishan D (Cao et al, 2002) Meishan where D 0 is a function of temperature and salinity and has been calculated with the R package marelac (Soetaert et al, 2016). Bioturbation is implemented as two separate processes: bio-mixing and bio-irrigation (Kristensen et al, 2012) following conventional descriptions (Boudreau, 1984;Meysman et al, 2010).…”

Section: Biozonesmentioning

confidence: 99%

Latest Permian carbonate-carbon isotope variability traces heterogeneous organic carbon accumulation and authigenic carbonate formation

Schobben¹,

Velde²,

Suchocka³

et al. 2017

Preprint

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Abstract. Bulk-carbonate carbon isotope measurements are a widely applied proxy for investigating the ancient biogeochemical carbon cycle. Temporal carbon isotope trends serve as a prime stratigraphic tool, with the inherent assumption that bulk micritic carbonate rock is a faithful geochemical recorder of the isotopic composition of seawater dissolved inorganic carbon. However, bulk-carbonate rock is also prone to incorporate diagenetic signals. The aim of the present study is to disentangle primary trends from diagenetic signals in carbon isotope records which traverse the Permian–Triassic boundary in marine carbonate-bearing sequences of Iran and South China. By pooling newly produced and published carbon isotope data we confirm that a global first-order trend towards depleted values exists. However, a large amount of scatter is superimposed on this geochemical record. In addition, we observe a temporal trend in the amplitude of this residual δ13C variability, which is reproducible for the two studied regions. We suggest that (sub)seafloor microbial communities and their control on calcite nucleation as well as on ambient porewater dissolved inorganic carbon-δ13C pose a viable mechanism to induce bulk-rock δ13C variability. Numerical model calculations highlight that early diagenetic carbonate rock stabilization, and linked carbon isotope alteration, can be controlled by organic matter supply and subsequent microbial remineralization. Low marine sulfate and a major biotic decline among late Permian bottom-dwelling organisms facilitated a spatial increase in heterogeneous organic carbon accumulation, causing varying degrees of carbon isotope overprint. A simulated time series suggests that a 50 % increase in the spatial scatter of organic carbon relative to the average, in addition to an imposed increase in the likelihood of sampling cements formed by microbial calcite nucleation to one out of 10 samples, is sufficient to induce the observed signal of carbon isotope variability. These findings put constraints on the application of Permian–Triassic carbon isotope chemostratigraphy based on whole-rock samples, which appears less refined than classical biozonation dating schemes. On the other hand, this signal of increased carbon isotope variability concurrent with the largest mass extinction of the Phanerozoic may inform about local carbon cycling mediated by spatially heterogeneous (sub)-seafloor microbial communities under suppressed bioturbation.

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Chemostratigraphy Across the Permian‐Triassic Boundary

Schobben¹,

Heuer²,

Tietje³

et al. 2018

Chemostratigraphy Across Major Chronological Boundaries

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Ocean's response to a changing climate: Clues from variations in carbonate mineralogy across the Permian–Triassic boundary of the Shareza Section, Iran

Cited by 24 publications

References 51 publications

Latest Permian carbonate carbon isotope variability traces heterogeneous organic carbon accumulation and authigenic carbonate formation

Latest Permian carbonate carbon isotope variability traces heterogeneous organic carbon accumulation and authigenic carbonate formation

Latest Permian carbonate-carbon isotope variability traces heterogeneous organic carbon accumulation and authigenic carbonate formation

Chemostratigraphy Across the Permian‐Triassic Boundary

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