Response of terrestrial environment to the Paleocene-Eocene Thermal Maximum (PETM), new insights from India and NE Spain

Abstract

The late Paleocene - Early Eocene boundary (56Ma) is marked by the warmest climate period of the Cenozoic, known as the Paleocene-Eocene Thermal Maximum (PETM). Most notably, the culprit behind it was a massive injection of heattrapping greenhouse gases into the atmosphere and oceans, comparable in volume to what our persistent burning of fossil fuels could deliver in coming centuries. The response of the oceanic and continental environments to the PETM is different. Many factors might control the response of the environments to the PETM such as paleogeography, paleotopography, paleoenvironment, and paleodepth. Herein, we present two different examples from terrestrial environment, their correlation with the marine record and their response to the PETM warming. In northwestern India, the establishment of wetland conditions and related thick lignite accumulations reflect the response of the continental environments to the PETM. This continental climatic shift towards more humid conditions led to migration modern mammals northward following the migration of the climatic belts. What remains uncertain is the timing and tempo of this mammal migration event and whether it originated in Asia or more specifically out of India. Biostratigraphy and carbon isotope analyses in three lignite mines located in NW India reveal the presence of both PETM and ETM2 organic carbon isotope negative excursions and demonstrate that modern mammals appeared in India after the PETM. Relative ages of this mammal event based bio-chemoand paleomagnetic stratigraphy support a migration path originating from Asia into Europe and North America, followed by later migration from Asia into India.