Paleomagnetic Constraint on the Age of the Shyok Suture Zone.

The India‐Eurasia collision is a key case study for understanding the influence of plate tectonic processes on Earth's crust, atmosphere, hydrosphere, and biosphere. However, the timing of the final India‐Eurasia continental collision is debated due to significant uncertainty in the age of the collision between the Kohistan‐Ladakh arc (KLA) and Eurasia along the Shyok suture zone. Here we present paleomagnetic results that constrain the Karakoram terrane in northwest India to a paleolatitude of 19.9 ± 8.9°N between 93 and 75 million years ago (Ma). Our results show that the Karakoram terrane was situated on the southern margin of Eurasia in the Late‐Cretaceous. Our results indicate that the KLA and Eurasian continent had a not converged until <61.6 Ma, placing a Paleocene older limit on the age of final closure of the Shyok suture zone. This suggests that the India‐Eurasia collision in northwestern India likely occurred after the closure of the oceanic basin between the KLA and Eurasia. The Paleocene collision event affecting India that has been widely interpreted to represent final India‐Eurasia collision instead records the arc‐continent collision between the KLA and the northern edge of India prior to final India‐Eurasia collision. Final India‐Eurasia collision in northwest India most likely occurred after the closure of the oceanic basin between the KLA and Eurasia. Plain Language Summary: We use the magnetism of rocks to determine the latitude of the southern edge of Eurasia before the India‐Eurasia continental collision. The results show that the southern edge of Eurasia was situated at 19.9 ± 8.9°N between 93 and 75 million years ago. This latitude means that a volcanic island chain called the Kohistan‐Ladakh arc (KLA) was situated significantly south of the Eurasian continent at the start of the India‐Eurasia collision. Our results suggest that the final stage of continental collision between India and Eurasia in northwest India occurred along the Shyok suture zone, a geological boundary where a major ocean basin once existed between the KLA and Eurasia. Key Points: The Karakoram terrane was on the Eurasian margin at 20°N between 93 and 75 MaThe final closure of the Shyok suture zone occurred after 61.6 million years agoThe Kohistan‐Ladakh arc accreted onto India prior to final India‐Eurasia continental collision [ABSTRACT FROM AUTHOR]