新疆博格达山地区古生代与中生代之交植物群演替

Upper Palaeozoic—Mesozoic continental deposits crop out along the northern and southern foothills of the Bogda Mountains, Xinjiang Uygur Autonomous Region. Abundant fossil plants are preserved in those deposits. The Bogda Mountains is an ideal place to do the research on floral successions during the Palaeozoic-Mesozoic transition, as well as vegetational responses to the end-Permian mass extinction event. During our previous work, several hundreds of specimens have been collected and analyzed, fundamental stratigraphic framework based on cyclostratigraphy and zircon dating has been established. In this project, we will focus on fossil plant taxonomy based on the collection from the Changhsingian, Induan and Olenekian deposits. Moreover, floral composition and succession will be analyzed. Finally, the influence of the end-Permian mass extinction event on terrestrial plants will be evaluated by multidisciplinary evidence.

新疆博格达山南、北两麓发育了连续的晚古生代—中生代陆相地层，且含有丰富的植物化石，是研究古生代—中生代之交植物群演替和二叠纪末大绝灭事件对陆生植物影响的理想区域。本课题拟立足于先期研究积累的数百块化石植物标本为基础，以基于旋回地层学、U-Pb锆石高精度定年数据建立的年代地层学作为基本保障，加之本课题设计的对区域内更多地质剖面的进一步工作，开展对古生代—中生代之交植物群的针对性研究。综合运用生物地层学、旋回地层学、锆石年代学、地球化学等手段限定二叠纪—三叠纪界线范围；深入开展植物系统分类学、植物古生态学等相关研究，力争全面揭示研究区长兴期、印度期和奥伦尼克植物群的整体面貌和演替规律，探索植物对二叠纪末生物大灭绝事件的响应状况。

本项目以我国新疆北部博格达山南、北两麓的二叠—三叠纪陆相地层以及其中的化石植物为研究对象，并通过化石中所蕴含的证据进行古气候学和古生态学研究。经过综合地层学的研究，重新厘定了研究区的晚二叠世—早三叠世地层框架，通过CA-ID-TIMS测年、岩石地层学、生物地层学和旋回地层学等方法，在吐鲁番南桃东沟剖面准确锚定P-T界线。通过化石木材学的研究，命名了5个裸子植物新属种，极大地丰富了研究区二叠纪末生物大灭绝之前陆地森林植被的多样性。利用化石植物中的古气候和古环境信号，推测了晚二叠世—晚三叠世的气候变化。