Timing of the India‐Kohistan Ladakh Arc and India‐Asia Collisions Based on Detrital Muscovite Provenance of the Indus Group, Ladakh, NW India

Abstract The juxtaposition of the Kohistan‐Ladakh arc (KLA) between the India and Asia plates in northwest India poses a unique challenge in determining the timing of the India‐Asia collision. The paramount question is whether the KLA collided first with India or Asia. To reconstruct the sequence of collisions, we present a new data set comprising >400 detrital muscovite single grain 40 Ar/ 39 Ar ages from the Indus Group—a key stratigraphic unit within the Indus Basin, along the Indus suture zone. Provenance analysis reveals the introduction of detrital muscovite from the Asian Pamir‐Karakoram region into the Indus Basin by ∼42–38 Ma. Building upon prior studies, we support a two‐stage model wherein the KLA collided with India by at least ∼60–50 Ma along the Indus suture zone, followed by the collision of the amalgamated India–KLA block with Asia, initiating the terminal India‐Asia collision along the Shyok suture zone by at least ∼42–38 Ma. This is the first stratigraphy‐based study in the Indus suture zone advocating for a more recent minimum age for the terminal India‐Asia collision, leveraging the largest reported detrital muscovite 40 Ar/ 39 Ar age data set from the Indus Basin. Within the broader framework of the ∼60–50 Ma collision in south Tibet, our results support a maximum 10–20 Myr diachronous east‐to‐west India‐Asia collision. Additionally, our data document the influx of Indian plate‐sourced muscovite into the upper sections of the Indus Group at ∼26–23 Ma, indicating exhumation of Himalayan metamorphic sources during the later stages of the India‐Asia collision.