EAPSI:EAPSI: Integrating English and Chinese-Language Literature on the India-Asia Collision to Better Understand the Formation and Evolution of Subduction Complexes

Metcalf Kathryn E, Tucson AZ

Investigators

Abstract

Before India and Asia collided, forming the Himalayas, the oceanic plate between the continents was subducted beneath Asia. The material scraped off from the oceanic plate during subduction, called a subduction complex, is one of the few records of the material that entered the subduction zone. Most of the material is subducted into the mantle and lost to the geologic record. Integrating data from Chinese-language and English-language sources will provide a holistic understanding of the subduction complex in southern Tibet. This project will analyze and compile maps and data available only in China with those from English-language publications and new data generated in the United States and China. This research will be conducted at the Institute of Tibetan Plateau Research in collaboration with Professor Ding Lin and his students, who have worked extensively on the subduction complex in southern Tibet. The collaboration could lead to the discovery of new continental fragments that were subducted and a new model for how subduction complexes develop. This project will integrate the extent, deformation style, and provenance of the subduction complex in southern Tibet. Primary data will be maps, unit descriptions, U-Pb detrital zircon geochronology, and sedimentary provenance. The subduction complex in southern Tibet is a complicated, little-studied unit that records the source and deformation of materials entering the subduction zone and that is composed almost entirely of block-in-matrix mélange, far thicker and more mixed than any other documented subduction complex. This block-in-matrix style of deformation over kilometers width in a few millions of years is unexplained by current subduction zone models. This award under the East Asia and Pacific Summer Institutes program supports summer research by a U.S. graduate student and is jointly funded by NSF and the Ministry of Science and Technology of China.