大印度在碰撞前的构造伸展量和古纬度演化过程是正确理解印度-欧亚大陆碰撞时限的前提。特提斯喜马拉雅早白垩世古地磁结果是解决大印度构造伸展和白垩纪运动学演化的关键科学问题。本项目拟通过对藏南错那-隆子地区拉康组剖面采取构造地质与古地磁相结合、同位素年代定年和磁性地层相结合，沉积岩与火山岩相结合的研究手段，厘定拉康组沉积时代，利用灰岩中的玄武岩夹层、磁倾角E/I校正技术和剩磁各向异性的倾角校正技术三种方法综合评定拉康组灰岩磁倾角浅化影响，获取在精确年代格架下东特提斯喜马拉雅早白垩世可靠的古地磁结果。基于东冈瓦纳大陆裂解前的古板块重建，通过对比澳大利亚板块西缘古地磁结果，探讨大印度在白垩纪的伸展规模和运动学演化过程，为印度-欧亚大陆碰撞启动时间提供约束。

The ancient Greater Indian plate plays an important part in understanding the timing and process of India-Asia collision, yet its pre-collisional extent has been difficult to estimate. Based on the geological mapping of eastern Tethyan Himalaya, this proposal plans to conduct systematic paleomagnetic and geochronological study on the Early Cretaceous Lakang Formation in Longzi-Cuona area of south Tibet. The results of this work will obtain well-dated Early Cretaceous poles of Greater India’s northern edge though magnetostratigraphy and geochronologic study. The acquisition of this paleolatitude, in combination with the paleomagnetic results from Tethyan Himalaya and Western Australia, allows us to constrain the size and kinematic north drift of Greater India, and further dating the onset of India-Asia collision.