Uplift, climate and biotic changes at the Eocene-Oligocene transition in south-eastern Tibet

• 来源期刊: 国家科学评论（英文版）
• 年，卷（期）: 2019,（3）
• 页码范围: 495-504
• 页数: 10页
• 语种: 英文
• DOI: 10.1093/nsr/nwy062

摘要

The uplift history of south-eastern Tibet is crucial to understanding processes driving the tectonic evolution of the Tibetan Plateau and surrounding areas.Underpinning existing palaeoaltimetric studies has been regional mapping based in large part on biostratigraphy that assumes a Neogene modernization of the highly diverse,but threatened,Asian biota.Here,with new radiometric dating and newly collected plant-fossil archives,we quantify the surface height of part of the south-eastern margin of Tibet in the latest Eocene (～34 Ma) to be ～3 km and rising,possibly attaining its present elevation (3.9 km) in the early Oligocene.We also find that the Eocene-Oligocene transition in south-eastern Tibet witnessed leaf-size diminution and a floral composition change from sub-tropical/warm temperate to cool temperate,likely reflective of both uplift and secular dimate change,and that,by the latest Eocene,floral modemization on Tibet had already taken place,implying modernization was deeply rooted in the Palaeogene.