昌都微地块早新生代运移过程的古地磁约束

本项目针对青藏高原东南缘侧向挤出和旋转变形过程存在争议这一现状，拟选择位于喜马拉雅东构造节东部和北部研究薄弱的昌都微地块开展早新生代-早中新世的精细古地磁学研究。该地块是条狭长的自西西北向南南东向渐进展布的条带，其几何形状可能是响应印度-欧亚板块碰撞围绕东构造结发生变形的弯山构造。针对弯山构造四个区域早新生代-早中新世不同时段广泛出露的沉积岩和火山岩地层，开展精细的古地磁测试分析和火成岩同位素年代学测定，以期获得四个区域早新生代-早中新世的纬向运移历史和旋转变形历史及其时空演化关系；同时，通过区域构造线迹方向变化与旋转的相关性分析和聚类统计分析，约束昌都微地块早新生代的整体旋转变形过程；对比周边已有的古地磁数据和地质证据，探讨高原东南缘在印度-欧亚板块碰撞过程中的侧向挤出和变形过程及其动力学机制。本项目的开展对于认识高原隆升变形过程和演化模式及动力学机制等具有重要意义。

To quantify the present debates on the southeastward extrusion and rotation of the southeastern Tibetan Plateau, this study aims to carry out detailed Early Cenozoic-Early Miocene paleomagnetic study of the poorly studied Qamdo micro-terrane. The terrane is a narrow strip gradually changed from WWN to ESS direction, which is likely an orocline belt around the eastern Himalaya syntaxis by the India-Asia collision. The work will carry out detailed paleomagnetic and geochronological studies of the well exposed Early Cenozoic-Early Miocene strata in four localities from different parts of the orocline belt, to obtain their latitudinal movement and rotation histories and establish their spatial and temporal correlations. Meanwhile, through correlation and cluster analysis of the regional tectonic lines with the paleomagnetic rotation results, we tempt to constrain the Early Cenozoic rotation process of the Qamdo micro-terrane. Then by comparing with the adjacent available paleomagnetic and geological evidence, we aim to decipher the extrusion and deformation processes and kinematics of the southeastern Tibetan Plateau during the India-Asia collision. This work will comprehensive understating on the uplift, deformation and kinematics of the Tibetan Plateau.