A pervasive tropical climate in SE Tibet 35.5 Ma ago
A global cooling of the Earth climate has characterized the Eocene-Oligocene transition that initiated the Antarctic glaciation ca. 33.7 Ma and a shift from greenhouse to icehouse conditions. What was the impact of these climatic changes in the continental realm, particularly in tropical regions affected by a monsoonal regime? A recent study published in Scientific Reports shows prevalent wet conditions in SE Tibet 35.5 Ma while a dry arid climate dominates the northern part of the Xining Basin. These results suggest a redistribution of moisture in tropical Asia most probably forced by a northern migration of the Intertropical Convergence Zone (ITCZ) around 35.5 Ma. This is in agreement with recent reconstructions of Sea Surface Temperatures (SST) in marine sediments in equatorial regions.
September 18, 2017