Equatorial heat accumulation as a long-term trigger of permanent Antarctic ice sheets during the Cenozoic

Maxime Tremblin (1) , Michaël Hermoso (2) , Fabrice Minoletti (1)

1 iSTeP - Institut des Sciences de la Terre de Paris
2 Department of Earth Sciences [Oxford]

The long-term cooling trend of the Cenozoic is punctuated by shorter-term climatic events, such as the inception of permanent ice sheets on Antarctica at the Eocene−Oligocene Transition (∼33.7 Ma). Taking advantage of the excellent state of preservation of coccolith calcite in equatorial Atlantic deep-sea cores, we unveil progressive tropical warming in the Atlantic Ocean initiated 4 million years prior to Antarctic glaciation. Warming preceding glaciation may appear counterintuitive, but we argue that this long-term climatic precursor to the EOT reinforced cooling of austral high latitudes via the redistribution of heat at the surface of the oceans. We discuss this new prominent paleoceanographic and climatic feature in the context of overarching pCO2 decline and the establishment of an Antarctic circumpolar current.

Domaines: Climatologie; Glaciologie

Maxime Tremblin, Michaël Hermoso, Fabrice Minoletti. Equatorial heat accumulation as a long-term trigger of permanent Antarctic ice sheets during the Cenozoic. Proceedings of the National Academy of Sciences of the United States of America, 2016, 113 (42), pp.11782-11787. ⟨10.1073/pnas.1608100113⟩. ⟨hal-01376097⟩