The challenge of quantification of ‘Greater India’ by paleomagnetism

古近纪印度板块与欧亚板块的碰撞导致了青藏高原的形成，并对气候系统产生了强烈影响。了解碰撞的年龄和方式对于了解喜马拉雅-西藏造山运动的演化至关重要。这一建议建议进行古地磁研究，以提高对印度板块北部边缘（大印度）碰撞前程度的认识，从而确定印度大陆与欧亚板块接触的年龄。北印度板块边缘特提斯-喜马拉雅（TH）的古近系序列只出现在三个位置。古地磁资料限制了大印度的大小，从TH西部（Gamba）开始；然而，它们的意义最近受到了质疑。第二个地点（定日），也在TH西部，尽管进行了几次尝试，但没有产生合适的结果。剩下的开放机会是TH西部的Zanskar山脉，从那里没有数据限制碰撞前的大印度范围。本文将以Zanskar地区晚古新世双闪石灰岩为研究对象，进行详细的古地磁研究和深入的岩石地磁分析，以表征剩余磁化的起源。这也将包括与Gamba等效序列的比较。如果成功，我们将获得一个大大改进的大印度范围数据集，并首次获得印度板块边缘西侧的此类数据集。

The continental collision of the Indian and Eurasian Plates in the Paleogene led to the formation of the Tibetan Plateau and strongly influenced the climate system. Knowing the age and mode of the collision is crucial for understanding the evolution of the Himalayan-Tibetan orogeny. This proposal suggests a paleomagnetic study to improve the knowledge on the pre-collision extent of the northern Indian Plate margin (Greater India), which is needed to determine the age when the continental Indian and Eurasian Plates got in contact. Paleogene sequences in the Tethyan Himalaya (TH) at the northern Indian plate margin only occur at three locations. Paleomagnetic data constraining the size of Greater India exist from the western TH (at Gamba); however, their significance was recently put into question. The second location (at Tingri), also in the western TH, did not yield suitable results despite several attempts. The remaining open opportunity is the Zanskar Range in the western TH, from where no data constraining the pre-collisional Greater India extent are yet available. The Late Paleocene Dibling Limestones in Zanskar will be the target of this proposal, conducting a detailed paleomagnetic study and in-depth rock magnetic analyses in order to characterize the origin of remanent magnetization. This will also include a comparison with the equivalent sequence at Gamba. If successful, we will gain a substantially improved data set constraining the Greater India extent, and obtain the first such data from the western side of the Indian Plate margin.