青藏高原及其周边地区早古近纪底栖大有孔虫的演化规律

特提斯喜马拉雅地区的下古近系沉积地层包含有印度-欧亚大陆初始碰撞的关键信息，在该地区建立高分辨率生物地层格架是精确约束初始碰撞年龄的前提条件之一。建立高分辨率生物地层的基础是准确了解沉积地层内古生物的发展演化规律。本项目拟以西藏古汝地区和巴基斯坦Balakot和Muzaffarabad地区的下古近系含大有孔虫碳酸盐岩沉积地层为研究对象，以野外剖面测量、样品密集采集和实验室内岩石薄片磨制为基础，在这些地区建立基于大有孔虫的、区域可对比的生物地层格架；结合同位素地球化学手段，查寻早古近纪一系列古环境古气候突变事件（尤其是古新世-始新世极热事件）在这些地区的保存情况；对于保存有突变事件的层位将进行重点研究，调查这些突变事件期间气候变化和碳循环的耦合关系、大洋缺氧情况以及大有孔虫对这些事件的具体响应过程，探讨大有孔虫在气候环境突变情况下的演化过程。最终揭示早古近纪大有孔虫在东特提斯洋的演化规律。

Lower Paleogene sedimentary rocks in the Tethyan Himalaya contain key information about the initial India-Asia continental collision. One of the prerequisites for precisely dating the initial collision is to construct high-resolution biostratigraphy in the sedimentary strata, which relies heavily on our understanding of biotic evolution preserved in these sedimentary strata. This project will investigate the lower Paleogene larger foraminiferal carbonate sequences exposed at Guru (south Tibet) and Balakot/Muzaffarabad (Pakistan). Based on section logging, densely sample collection in the field and thin-sections in the laboratory, a regional high-resolution larger foraminiferal biostratigraphy will be constructed. Combined with isotopic geochemical data, the preservation of a series of paleoclimatic and paleoenvironmental events (particularly the Paleocene-Eocene thermal maximum) in these areas will be explored. For stratigraphic intervals preserving some of these events, special efforts will be made to understand the relationship of climate change and carbon cycling, the extent of ocean anoxia, and response of larger benthic foraminifera to these events. In the end, evolution of the early Paleogene larger benthic foraminifera in eastern Neo-Tethyan Ocean will be elucidated.