Latitude of the Lhasa terrane since the Paleocene: Implications for the India–Asia collision and Tibetan crustal shortening

This is the authors' abstract. We don't add key points for this paper.

As the distal end of the southern margin of Asia, the Late Cretaceous–Cenozoic paleolatitude of the Lhasa terrane provides a key kinematic constraint for understanding India–Asia collision and the subsequent uplift history of the Tibetan Plateau. However, its Paleogene paleolatitude remains debated. Here we report a robust paleomagnetic pole at 69.2°N, 297.2°E with an A95 = 5.2°, where A95 is the 95% confidence cone of Fisher statistics, calculated from ca. 57 Ma dikes in the Shiquanhe area of Tibet, which corresponds to a paleolatitude of 15.4° ± 5.2°N for the westernmost Lhasa terrane. Positive baked-contact tests confirm that the characteristic remanent magnetization directions are primary magnetizations acquired when magma intruded. By applying a parametric resampling method to synthesize regional paleomagnetic datasets, we provide a more rigorous assessment of latitudinal displacements and associated uncertainties. We conclude that the Lhasa terrane underwent stepwise northward motion during ca. 58–55 Ma and ca. 36–27 Ma, reaching its present latitude by ca. 27 Ma. This was accomplished by the multistage India–Asia collision and the corresponding crustal shortening. Comparison of paleolatitudes among the Lhasa terrane, the Tethyan Himalaya, Kohistan–Ladakh arc, India, and Eurasia shows that the Indian plate first collided with the Kohistan–Ladakh arc during ca. 64–63 Ma and sutured with Asia during ca. 51–49 Ma. Furthermore, we quantify the magnitude and duration of crustal shortening between different geological units across the plateau since the initial India–arc collision, providing a kinematic framework that aligns with the gradual surface uplift of the Gangdese arc, the Lhasa–Qiangtang suture, and the Himalaya.