The challenge of quantification of ‘Greater India’ by paleomagnetism

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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.