Constraining the Nature and Formation Age of the Shyok Suture Zone in Ladakh, NE India

Massachusetts Institute Of Technology, Cambridge MA

Investigators

Abstract

The spectacular height and length of the Himalayan Mountain Belt has inspired generations of people across the world. The mountain chain was formed during the collision of the Indian and Eurasian continents approximately 40-50 million years ago. Before this collision occurred, an ocean called the Neotethys separated the two continents and the timing of its disappearance remains an open question. This project will better constrain the timing of the collision between the two continents by age dating and paleomagnetic measurements in the Kohistan-Ladakh region of northern India. A better constraint on the timing of the collision and disappearance of the Neotethys ocean is essential not only for our understanding of the Himalayas, but also for addressing other big questions such as the how tectonic plates reorganize during major collisional events and the influence of tectonic forces on global climate. The principal goals of this project are to better constrain the nature and age of the Shyok suture zone, and to test alternative models for the Kohistan-Ladakh-Eurasia collision. If the Shyok suture is younger than the Indus suture, then the Shyok-Tsangpo suture zone, not the Indus-Tsangpo suture zone, records the final collision of India and Asia, and two subduction systems were present in the Neotethys ocean until approximately 50 Ma. We will conduct a detailed study combining field geologic mapping, petrology/geochemistry, U-Pb zircon geochronology, and paleomagnetic measurements. This work will constrain the currently unknown age and provenance of multiple sedimentary sequences in the suture zone as well as provide new information on the geochemical characteristics and ages of plutonic rocks within the suture and in neighboring terranes. Additionally, the proposed paleomagnetic work will determine the unknown paleolatitudes of both the Kohistan-Ladakh arc and Eurasian margins during the crucial time of the India-Eurasia collision and thus allow us to evaluate the different collision scenarios. The work related to this project constitutes a comprehensive and multifaceted documentation of a pivotal yet unconstrained suture zone in the Himalaya and offers the opportunity to capitalize on the recently increased access to crucial exposures in Ladakh, India. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.