Palaeocene–Eocene carbon isotopic excursion from the shallow-marine-carbonate sequence of northeast India: Implications on the CIE magnitude and geometry

Journal of earth system science

Sruthi P Sreenivasan^1¹  Melinda Kumar Bera^1² 

[1] Department of Geology and Geophysics, Indian Institute of Technology, Kharagpur 721 302, India.^1;Department of Geology, Asutosh College, Kolkata 700 026, India.^2

关键词: Palaeocene–Eocene thermal maximum;    carbon isotope excursion;    NE India;    marine carbonate;    Sylhet Limestone;   

DOI  :  

学科分类：天文学(综合)

来源: Indian Academy of Sciences

【 摘 要 】

The exact magnitude of the carbon isotopic excursion (CIE) for the Palaeocene–Eocene Thermal Maximum (PETM) is essential for our understanding of the carbon cycle perturbation. Global compilation of the PETM CIE magnitudes indicates that the shallow-marine inorganic carbonate could be a potential candidate to decipher the actual CIE magnitude. The present study, therefore, made an attempt to explore the thick Palaeogene shallow-marine carbonate sequence of the Sylhet Limestone exposed in the Jaintia Hills of northeast (NE) India, in terms of the preservation and magnitude of the PETM CIE. Exploratory sampling carried out across the Sylhet Limestone suggests that this sequence was deposited during the Late Palaeocene and Early Eocene, as evident from the age-diagnostic foraminifera. The observed ${\sim }$3.4 per thousand CIE at the top of the Lakadong Limestone, resting above the Miscellanea miscella and Ranikothalia nuttalli foraminifera-bearing horizon, can, therefore, be correlated with the PETM CIE. Although the magnitude of the CIE from our limited data set agrees well with the global compilation, the absence of a stepped profile questions the preservation of the CIE reported elsewhere from the Tethyan sequence. Further work is needed for a better understanding of the PETM interval in NE India.

【 授权许可】

CC BY