拉萨-冈底斯地块白垩系孢粉植物群研究

The Lhasa-Gandise block represents the frontier of the Eurasia in its collision with the Indian Plate and thus is the most sensitive region to the Indo-Eurasian collision. So far, little is known about the palaeovegetation on this block during the Cretaceous or, the night before the collision. In this research, we will focus on palynology on the Cretaceous successions at the most representative areas of this region, including Baxoi, Lhorong, Baingoin and Gêrze counties. Through detailed systematic classification, identification and statistics, the compositional features and evolution history of the palynofloras will be described in detail through the Cretaceous Period. The palaeogeography and palaeoclimate will be analyzed and major vegetation transition events will be investigated according to the main components and characteristic markers of the vegetation. The influencing factors and geological significance of these evolutionary events in the palaeovegetation will also be discussed through regional and global correlation. The research will provide indispensable background knowledge of the terrestrial ecosystem for the study on how the Indo-Eurasian plate collision impact the regional biotas and palaeoenvironments.

拉萨-冈底斯地块位于印度-欧亚板块碰撞的前缘地区，对印度-欧亚板块碰撞的反应最直接也最敏感。但是目前为止，人们对区内白垩纪这一印度-欧亚板块碰撞前夜的古植被所知甚少。本课题计划以八宿-洛隆、班戈和改则等该区白垩系代表性地区为重点选择合适剖面开展孢粉学研究，通过对其中的孢粉化石进行详细的系统分类和鉴定统计，分析揭示区内白垩纪孢粉植物群组成面貌和演化历史，根据植被主要成分和特征指示分子分析古地理、古气候和重大植被转型事件，通过区域和全球性对比分析、探讨驱动古植被演化的影响因素和地质意义，为研究印度-欧亚板块碰撞对区域古生物和古环境的影响提供必需的陆地生态系统背景知识。

拉萨-冈底斯地块是青藏高原的重要组成部分，目前为止，人们对其白垩纪的古植被所知甚少，孢粉学研究处于空白。本课题计划以八宿-洛隆、班戈和改则等区内代表性白垩系发育地区为重点选择合适剖面开展孢粉学研究，通过孢揭示区内白垩纪孢粉植物群组成面貌和古植被演化历史，并尝试探讨古地理、古气候和古植被演化的影响因素等科学问题。课题在执行期间对上述地区开展了广泛的野外地质考察，实测、采集了12条地层剖面开展研究。从藏东拉贡塘组、多尼组，申扎和改则一带的多尼组中获得了丰富的孢粉化石，首次构建了拉萨-冈底斯块体晚侏罗世至晚白垩世孢粉组合序列，包括晚侏罗世Classopollis高含量组合、早白垩世早期贝里阿斯期-巴雷姆期Classopollis-Dicheiropollis组合、早白垩世晚期阿普特期–阿尔布期Bisaccates–Ephedripites (Spiralipites)组合和晚白垩世早期赛诺曼期–早三冬期Ephedripites (Spiralipites)–Classopollis–Exesipollenites组合，重建了区内古植被和古气候历史，指出晚侏罗世晚期至早白垩世早期气候干热，早白垩世晚期，气候有所变凉、变湿，晚白垩世气候再次转向干旱、温暖。课题共发表10篇期刊论文，其中SCI论文8篇、NI期刊论文1篇，同时还在本领域有影响力的期刊“Palaeogeography, Palaeoclimatology, Palaeoecology（三古）”和“Journal of Asian Earth Sciences（亚洲地质）”上组织出版相关研究主题专辑2部。课题圆满完成了预定的研究任务，实现了研究目标。