Orbital climate variability on the northeastern Tibetan Plateau across the Eocene–Oligocene transition

Hong Ao (1) , Guillaume Dupont-Nivet (2, 3, 4) , Eelco Rohling (5) , Peng Zhang , Jean-Baptiste Ladant , Andrew Roberts , Alexis Licht , Qingsong Liu , Zhonghui Liu , Mark Dekkers , Helen Coxall , Zhangdong Jin , Chunju Huang , Guoqiao Xiao , Christopher Poulsen , Natasha Barbolini , Niels Meijer , Qiang Sun , Xiaoke Qiang , Jiao Yao , Zhisheng An

1 CAS - Chinese Academy of Sciences [Beijing]
2 GR - Géosciences Rennes
3 Key Laboratory for Orogenic Belts and Crustal Evolution
4 University of Potsdam = Universität Potsdam
5 ANU - Australian National University

The first major build-up of Antarctic glaciation occurred in two consecutive stages across the Eocene-Oligocene transition (EOT): the EOT-1 cooling event at ~34.1-33.9 Ma and the Oi-1 glaciation event at ~33.8-33.6 Ma. Detailed orbital-scale terrestrial environmental responses to these events remain poorly known. Here we present magnetic and geochemical climate records from the northeastern Tibetan Plateau margin that are dated precisely from ~35.5 to 31 Ma by combined magneto- and astro-chronology. These records suggest a hydroclimate transition at ~33.7 Ma from eccentricity dominated cycles to oscillations paced by a combination of eccentricity, obliquity, and precession, and confirm that major Asian aridification and cooling occurred at Oi-1. We conclude that this terrestrial orbital response transition coincided with a similar transition in the marine benthic δO record for global ice volume and deep-sea temperature variations. The dramatic reorganization of the Asian climate system coincident with Oi-1 was, thus, a response to coeval atmospheric CO decline and continental-scale Antarctic glaciation.

Domaines: Stratigraphie

Hong Ao, Guillaume Dupont-Nivet, Eelco Rohling, Peng Zhang, Jean-Baptiste Ladant, et al.. Orbital climate variability on the northeastern Tibetan Plateau across the Eocene–Oligocene transition. Nature Communications, 2020, 11 (1), pp.5249. ⟨10.1038/s41467-020-18824-8⟩. ⟨insu-03006953⟩