Tibetan plateau aridification linked to global cooling at the Eocene-Oligocene transition

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Abstract

Continental aridification and the intensification of the monsoons in Asia are generally attributed to uplift of the Tibetan plateau and to the land-sea redistributions associated with the continental collision of India and Asia1-3, whereas some studies suggest that past changes in Asian environments are mainly governed by global climate4-6. The most dramatic climate event since the onset of the collision of India and Asia is the Eocene-Oligocene transition, an abrupt cooling step associated with the onset of glaciation in Antarctica 34 million years ago7-9. However, the influence of this global event on Asian environments is poorly understood. Here we use magnetostratigraphy and cyclostratigraphy to show that aridification, which is indicated by the disappearance of playa lake deposits in the northeastern Tibetan plateau, occurred precisely at the time of the Eocene-Oligocene transition. Our findings suggest that this global transition is linked to significant aridification and cooling in continental Asia recorded by palaeontological and palaeoenvironmental changes10-12, and thus support the idea that global cooling is associated with the Eocene-Oligocene transition13-15. We show that, with sufficient age control on the sedimentary records, global climate can be distinguished from tectonism and recognized as a major contributor to continental Asian environments.

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