Organic carbon isotope records of the Paleocene- Eocene thermal maximum event in India provide new insights into mammal origination and migration

摘要

Early Eocene rift basins sediments in western and northwestern India contain deposits including lignite. These rift basins were formed during the early stage of the India - Eurasia collision. The Sedimentary successions in the studied five lignite mines are stratigraphically similar. In these successions, there are two thick lignite units, called the lower and upper lignite units, separated by early Eocene marine transgression deposits. Two organic carbon isotopes excursions are present, based on biostratigraphic age control, the lower carbon isotope excursion is linked to the Paleocene Eocene Thermal Maximum (PETM) and an upper one represents the Eocene Thermal Maximum-2 (ETM2). The correlation of obtained results to the global isotopic records from both marine and terrestrial environments indicates that mammal bearing intervals from India?s lignite mines were deposited in the late early Eocene, and that lends support to the hypothesis of mammal migration into India.