Tectonic and Climatic Impacts on Environmental Evolution in East Asia During the Palaeogene

Palaeogene environmental evolution in East Asia remains ambiguous. Here we present integrative work including magnetostratigraphy, grain-size, geochemistry, and clay mineralalogy from a 1609 m-thick fluviolacustrine sequence in eastern China. The results reveal two periods of tectonic control alternating with three periods of climatic control on the sedimentary evolution. Tectonic activity in the study area, as revealed by particle coarsening and reduced weathering, occurred during 65.6-59 Ma and strengthened in Asia during 55-54 Ma in response to the India-Eurasia collision. Weathering gradually enhanced in East Asia during 59-55 Ma, probably caused by global warming. Continuous global warming during 54-50.5 Ma is responsible for enhanced aridification in East Asia. From 50.5 to 37.6 Ma, global cooling weakened evapotranspiration and increased westerlies-derived moisture. Both aspects increased effective moisture and chemical weathering in East Asia. These results shed light on how alternating tectonism and climate change impacted environmental evolution in Asia during the Palaeogene.

Automated summary

This study reveals the complex interplay between tectonic and climatic controls on sedimentary evolution in East Asia during the Palaeogene, with tectonic activity influencing geological environments through particle coarsening and reduced weathering, while climate factors impacting East Asia through global warming and cooling episodes.