Is Tibetan Plateau uplift more recent than we thought?
Abstract
The uplift of the Tibetan Plateau critically impacted Asian climate and could have played a significant role in Cenozoic global cooling. However, the early topographic history of the Tibetan Plateau is uncertain, and most recent studies propose an old, high plateau as early as the Eocene, 40 to 50 million years ago. These studies rely on two types of approaches: proxies for past aridity north of Tibet, which are thought to track the onset of Tibetan orographic effects on precipitation, and clumped and stable isotope paleoaltimetry on Tibetan carbonates that, with the aid of models, can provide quantitative estimates of past altitude. Here, we review the assets and drawbacks of these different approaches for the Eocene in the light of new isotopic data and climate simulations. We show that most of the climatic assumptions required for the use of these two types of approach are invalid for Eocene Asia. In contrast, Eocene stable isotopic data appear more compatible with lower-elevation scenarios when compared with climate simulations, which is in greater agreement with Eocene paleobotanical data. These lower estimates contradict the Andean-type nature of the Tibetan Plateau but are more in line with geodynamic models proposing a recent (Neogene) uplift. We show that using climate models in conjunction with geological data provides a powerful tool to incorporate climatic changes into the analysis of paleoelevation and should be incorporated into future paleoaltimetry work.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMGP51A..05L
- Keywords:
-
- 1525 Paleomagnetism applied to tectonics: regional;
- global;
- GEOMAGNETISM AND PALEOMAGNETISM;
- 1616 Climate variability;
- GLOBAL CHANGE;
- 8157 Plate motions: past;
- TECTONOPHYSICS;
- 8177 Tectonics and climatic interactions;
- TECTONOPHYSICS