Journal of Asian Earth Sciences 212 (2021) 104736 Available online 16 March 2021 1367-9120/© 2021 Elsevier Ltd. All rights reserved. Organic carbon isotope records of the Paleocene- Eocene thermal maximum event in India provide new insights into mammal origination and migration Hassan Khozyem a, * , Thierry Adatte b , Gerta Keller c , Jorge E. Spangenberg d a Department of Geology, Faculty of Science, Aswan University, 81528 Aswan, Egypt b Institute of Earth Sciences (ISTE), University of Lausanne, 1015 Lausanne, Switzerland c Department of Geosciences, Princeton University, Guyot Hall, Princeton, NJ 08544, USA d Institute of Earth Surface Dynamics (IDYST), University of Lausanne, 1015 Lausanne, Switzerland A R T I C L E INFO Keywords: India Lignite PETM ETM2 δ 13 C org Mammal ABSTRACT 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 fve 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. 1. Introduction The late Paleocene-early Eocene transition (~56 Ma) is marked by the warmest climate period of the Cenozoic, known as the Paleocene- Eocene Thermal Maximum (PETM). Study of this climate warming gained new importance as potential analogue to the human-caused climate change unfolding today (Zachos et al. 2001; 2005; Norris et al., 2013). During the PETM massive injection of heat-trapping greenhouse gases into the atmosphere and oceans that are comparable in volume to the persistent burning of fossil fuels and its projections for the coming decades to centuries. But there is one critical difference: today’s injection of greenhouse gases magnitude is faster than that opserved during the PETM potentially leading to more severe climate warming and mass extinctions (see refs. in Keller et al., 2018). During the PETM, surface and deep oceans experienced temperature increases of 3–4 ◦ C and 6 ◦ C respectively (Kennett and Stott, 1991). The global temperature increase over 10,000 years is associated with nega- tive carbon isotope shifts in both carbonate and organic matter, which are linked to strong perturbations in the carbon cycle over about 150,000–220,000 years (Westerhold et al., 2009; McInerney and Wing, 2011). Injection of huge amounts of CO 2 in marine and atmospheric systems during the PETM were the main reasons for these perturbations. Excess CO 2 results in increased the ocean acidity and salinity, which is attributed to shoaling of the CCD (e.g., Zachos et al., 2005; Zeebe, 2012; Gutjahr et al., 2017) that coincides with extinctions in deep water benthic foraminifera (Speijer and Wagner 2002; Alegret et al., 2009). In the oceans surface water, nearly all planktic foraminifera are tempo- rarily absent during the PETM, except for the transient occurrence of few species (Acarinina africana, A. sibaiyaensis, Morozovella allisonensis; Kelly et al., 1996; Lu et al., 1998; Luciani et al., 2007; ; Keller et al., 2018). Similarly, most calcareous nannofossils temporarily disappeared leaving an impoverished Rhomboaster spp. Discoaster araneus assemblage (Kho- zyem et al., 2013). Terrestrial environments responded differently to the PETM; Increased atmospheric CO 2 resulted in warming and migration of climate belts poleward (Shellito et al., 2003; Foreman et al., 2012) associated with enhanced silicate weathering, runoff and formation of thick paleosoils. In India, increased humidity resulted in wetlands for- mation where thick lignite deposits accumulated. However, a major limiting factor in P-E studies of these lignite deposits is the fate of excess carbon at the end of the PETM, which is poorly constrained. The drawdown of atmospheric carbon dioxide is attributed to increased weathering of silicates, vegetation and/or increased rates of organic carbon burial (Zeebe et al., 2009; Bains et al., 2000; Dickens, * Corresponding author. E-mail address: h.m.khozyem@aswu.edu.eg (H. Khozyem). Contents lists available at ScienceDirect Journal of Asian Earth Sciences journal homepage: www.elsevier.com/locate/jseaes https://doi.org/10.1016/j.jseaes.2021.104736 Received 13 October 2019; Received in revised form 26 February 2021; Accepted 5 March 2021