第七届青年地学论坛

Asian environmental evolution and its relationship with global climate and regional tectonism after initiation of Asian monsoon climate have been widely investigated. However, few records are available to distinguishing their relationship when Central Asia was controlled by planetary wind belts. Here we present first evidence from the eolian red clay sequence (~51-39 Ma) in the Altyn Mountains of the northeastern Tibetan Plateau based on the environmental magnetism and diffuse reflectance of spectroscopy data. The results demonstrate clear three stages evolution of Central Asian environment, consistent with independent evidence of three stages advance-retreat variations of the Paratethys sea. This pattern suggests Central Asian environmental variations was dominant controlled by the Paratethys area variations. This is in contrast with previous results demonstrating global climate forcing on Central Asian paleoenvironment based only on magnetic susceptibility records. Furthermore, our results also suggest that appearance of the red clay sediments was controlled by sinking air in Central Asia but not necessarily associated with Siberia High Pressure system, and multiple Myr paleoenvironmental reconstruction must consider provenance variations.
 

Environmental magnetism; Environmental change; Red clay; Eocene; Central Asia