目前的全球气候变化已对植被生态系统产生巨大的影响，而地质历史时期中发生的类似事件将为我们更好的了解和预测目前植被对全球气候变化可能的响应提供参考。本项目拟基于前期在新生代柴达木盆地大红沟剖面已完成的野外和室内研究工作，进一步深入研究始新世-中新世河湖相沉积物中生物标志物。通过陆生高等植物叶蜡中的长链正构烷烃的单体碳同位素和孢粉的研究恢复当时的植被面貌，了解C4植物是否已在当时生态系统中占有一定比例，并通过测试其C35的碳同位素进一步验证C4植物的出现；通过孢粉各组分含量、碳酸盐岩氧同位素以及陆生高等植物叶蜡中的单体氢同位素的研究重建柴达木盆地古环境和古气候的演变。本项目最终目的在于调查青藏高原柴达木盆地始新世-中新世气候变化对植被的影响，为目前由人类活动导致的全球变化对植被和生态系统的影响提供可能的借鉴。

Presently, global climate change has posed serious effect on the vegetation of our ecosystem. The similar events occurred in the past may provide valuable information for our understanding and preparation to the possible vegetation response due to the global climate change. This project is designed to be a complementary part to our previous study which has been conducted for several years, targeting on key transitions of climate and vegetation evolution in the Cenozoic northeastern Tibetan Plateau. Based on the proposed project and previous work on ancient lacustrine sediments preserved in Dahonggou section, Qaidam Basin, vegetation visage (C4 plants) through Eocene to Miocene of this region will be reconstructed by using data of pollen and calculations involving both compound-specific carbon isotopes of higher plant lipids and pollen analysis. The appearance of C4 plants will also be supported by the evidence of compound-specific carbon isotopes of C35 from higher plant alkanes. The paleoenvironmental and paleoclimatic evolution will be also reconstructed by analyzing pollen assemblage, carbonate oxygen stable isotopes and compound-specific hydrogen isotopes of leaf lipids. Thus, the relationship between climatic change and vegetation replacement through the Eocene-Miocene of the Qaidam Basin may be revealed, which may thus provide us clues to the current vegetation response to the climate change.