Late Paleocene–early Eocene carbon isotope stratigraphy from a near-terrestrial tropical section and antiquity of Indian mammals

Journal of Earth system science

A Sarkar1¹  Jyotsana Rai2²  S S Rathore3³  A Samanta1¹  M K Bera1¹ 

[1] Department of Geology and Geophysics, Indian Institute of Technology, Kharagpur 721 302, India.$$;Birbal Sahni Institute of Palaeobotany, Lucknow 226 007, India.$$;KDM Institute of Petroleum Exploration, Dehradun 248 195, India.$$

关键词: Tropical terrestrial Paleocene–Eocene thermal maximum (PETM);    early Eocene hyperthermals;    carbon isotope excursion;    modern order mammal.;   

DOI  :  

学科分类：天文学(综合)

来源: Indian Academy of Sciences

【 摘 要 】

Late Paleocene to early Eocene (∼56 to 51 Ma) interval is characterized by five distinct transient warming (hyperthermal) events (Paleocene–Eocene thermal maximum (PETM), H1/ETM2/ELMO, H2, I1 and I2) in a super greenhouse globe associated with negative carbon isotope excursions (CIEs). Although well-documented marine records exist at different latitudes, terrestrial PETM sections are rare. In particular, almost no terrestrial records of either the PETM or early Eocene hyperthermals (EEHs) are yet available from the tropics. Further, evolution of modern order of mammals near the PETM has been recorded in many northern continents; however, the response of mammals in the tropics to these warming events is unknown. A tropical terrestrial record of these hyperthermal/CIE events, encompassing the earliest modern order mammal bearing horizon from India, can therefore be vital in understanding climatic and biotic evolution during the earliest Cenozoic time. Here, for the first time, we report high resolution carbon isotope (𝛿13C) stratigraphy, nannofossil, and Sr isotope ratio of marine fossil carbonate from the Cambay Shale Formation of Western India. The record shows complete preservation of all the above CIE events, including the PETM, hitherto unknown from the equatorial terrestrial records. 𝛿13C chemostratigraphy further suggests that at least the present early Eocene mammal-bearing horizon, recently discovered at Vastan, does not support the `out of India' hypothesis of earliest appearance of modern mammals and subsequent dispersal to the Holarctic continents.

【 授权许可】

Unknown