Organic fraction of the total carbon burial flux deduced from carbon isotopes across the Permo-Triassic boundary at Meishan, Zhejiang Province, China

Abstract

By combining the carbon cycle model with the records of carbonate and organic (kerogen) carbon isotope, this paper presents the calculation of the fraction of organic carbon burial (f org ) of beds 23-40 at the global boundary stratotype section and point (GSSP) of the Permian-Triassic boundary at Meishan, Zhejiang Province. The resulting calculation produces two episodes of f org maxima observed to occur at beds 23-24 and 27-29, which respectively corresponds to the two episodic anoxic events indicated by the flourish of green sulfur bacteria. Two episodic f org minima occurred at beds 25-26 and 32-34, generally coincident with the flourish of cyanobacteria (bed 26 and upper part of beds 29 to 34) as shown by the high value of 2-melthyhopnoanes. It appears that the f org is related to the redox conditions, with greater f org values observed under the reductive condition. The relationship between f org and the total organic carbon (TOC) content was complex. The f org value was low at some beds with a high TOC content (such as bed 26), while high observed at some beds with a low TOC content (e.g. bed 27). This association infers the important contribution of primary productivity to the TOC content. The original organic burial could be thus calculated through the configuration of the function of the primary productivity and f org , which can be used to correct the residual TOC measured today. This investigation indicates that compiling the organic-inorganic carbon isotopes with the carbon cycle model favors to understand the fraction of organic carbon burial, providing information for the reconstruction of the coupling among biota, environments and organic burial.

Relationships between carbon isotope evolution and variation of microbes during the Permian–Triassic transition at Meishan Section, South China

“…In the studied section d 13 C kero values varied from -25.4 to -32.7%, with a range as large as 7.3% ( Fig. 2), which is comparable with the data reported by Huang et al (2007a). Like the variation pattern in the carbonate carbon isotope values reported by Xie et al (2007a), the kerogen carbon isotope composition also decreased gradually from the upper part of bed 23 to bed 24e except for two episodes of slight increase in beds 24a and 24d, but the amplitude of these two episodes of increase were smaller than that of the corresponding n-C 19 alkane compound-specific carbon isotope values (Fig.…”

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

“…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).…”

Geobiological approach to evaluating marine carbonate source rocks of hydrocarbon

“…Research has shown that high f org corresponds to anaerobic condition whereas low f org corresponds to oxic condition [25]. In the global scale, the ups and downs of f org [5] echo those of organic burial flux [36] since Phanerozoic.…”

“…If f org is used to represent the paleo-oxygenation regime of OC sed , it would turn out that TOC does not always correlate positively with f org , but stands for a balance between PP and f org , as discussed in ref. [25]. Table 1 Paleo-oxygenation regimes [24] Dissolved oxygen (ml/L) Paleo-oxygenation regimes…”

“…Thus, we have the following HT order according to respective PP: Ⅱ 2 , Ⅶr, Ⅱ 1 , Ⅲ 1 , Ⅲ 2 , Ⅳ 1 , Ⅳ 2 , Ⅴ, Ⅰ, Ⅵ. Ba xs : Ba xs is ranked according to its direct relationships with PP [25,28]. According to the formulas given by Dymond et al [44] and Francois et al [4], the PPs (gC/m 2 yr) corresponding to Ba xs expressed in Table 4 in descending order are: >400, 200-400, 100-200, 50-100, <50 respectively.…”