A model of plate tectonic framework for the Southeast Asia margin in the mid-Cretaceous

Abstract

The recent IODP drillings in the South China Sea (SCS) have greatly enhanced our understanding of the tectonics and evolution of the SCS, but also raised new questions on the opening of the SCS and the pre-SCS tectonic history. Recently available data on the South China block (SCB), SCS, Indochina block, Borneo, Sumatra, Andaman, Myanmar, and the Tibetan plateau allow an updated tectonic model for the Southeast Asian margin in the mid-Cretaceous (around 100 Ma). A global scale granitoid belt can be readily identified from Sikhote-Alin in the north all the way to Northwest Borneo and to the Qiangtang terrane, as representing a giant magmatic arc system in response to the direction change of the subduction of the Izinagi plate and the Indian-Australian plate at ~100 Ma. This global subduction/magmatic system was displaced in the Early Cenozoic as the result of India-Asian collision, followed by the development of the escape tectonics characterized by strike-slip fault systems. The subsequent rifting further broke and dispersed the granitoid belts into fragments to the present locations in the Greater Southeast Asian tectonic realm.