TY  - JOUR
A1  - Bougeois, Laurie
A1  - Dupont-Nivet, Guillaume
A1  - de Rafelis, Marc
A1  - Tindall, Julia C.
A1  - Proust, Jean-Noel
A1  - Reichart, Gert-Jan
A1  - de Nooijer, Lennart J.
A1  - Guo, Zhaojie
A1  - Ormukov, Cholponbelk
T1  - Asian monsoons and aridification response to Paleogene sea retreat and Neogene westerly shielding indicated by seasonality in Paratethys oysters
JF  - Earth and planetary science letters
N2  - Asian climate patterns, characterised by highly seasonal monsoons and continentality, are thought to originate in the Eocene epoch (56 to 34 million years ago - Ma) in response to global climate, Tibetan Plateau uplift and the disappearance of the giant Proto-Paratethys sea formerly extending over Eurasia. The influence of this sea on Asian climate has hitherto not been constrained by proxy records despite being recognised as a major driver by climate models. We report here strongly seasonal records preserved in annual lamina of Eocene oysters from the Proto-Paratethys with sedimentological and numerical data showing that monsoons were not dampened by the sea and that aridification was modulated by westerly moisture sourced from the sea. Hot and arid summers despite the presence of the sea suggest a strong anticyclonic zone at Central Asian latitudes and an orographic effect from the emerging Tibetan Plateau. Westerly moisture precipitating during cold and wetter winters appear to have decreased in two steps. First in response to the late Eocene (34-37 Ma) sea retreat; second by the orogeny of the Tian Shan and Pamir ranges shielding the westerlies after 25 Ma. Paleogene sea retreat and Neogene westerly shielding thus provide two successive mechanisms forcing coeval Asian desertification and biotic crises.
KW  - Eocene monsoon
KW  - aridification
KW  - Paratethys sea
KW  - Central Asia
KW  - seasonality
KW  - bivalves
Y1  - 2018
U6  - https://doi.org/10.1016/j.epsl.2017.12.036
SN  - 0012-821X
SN  - 1385-013X
VL  - 485
SP  - 99
EP  - 110
PB  - Elsevier
CY  - Amsterdam
ER  -