Lignite deposits of the Kutch Basin, western India: Carbon isotopic and palynological signatures of the early Eocene hyperthermal event ETM2

•The first record of ETM2 hyperthermal event from the Kutch Basin, Gujarat, India.•Earliest Ypresian age is evident by palynological data for lignitic succession.•Data reiterates Lutetian age for vertebrate-bearing post-lignite succession.•The lignitic units of the Kutch & Cambay basins of western India are broadly coeval.

This study presents new results of combined palynological and stable carbon isotope (δ13C) investigations carried out in the well known lignite sequence at Panandhro, District Kutch, in the Gujarat state of western India. Dinoflagellate cysts and associated spore-pollen assemblage assign an early Eocene (Ypresian) age to the lignitic succession at Panandhro. Furthermore, a pronounced negative Carbon Isotope Excursion (CIE) of about 2.7‰, correlated to the Second Eocene Thermal Maximum (53.7 Ma), a globally recognized hyperthermal event, was discovered in the middle part of the succession, consistent with the palynological constraints. This is the first record of an Eocene hyperthermal event (ETM2) from the Kutch Basin. Our data has regional implications for the age of the lignitic sequences across western India as it demonstrates that there is no significant age difference between the lignite deposits of the Kutch and Cambay basins. Our results also support a Lutetian age for the previously described vertebrate fossils, including whales, from the Panandhro mine section.

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