Seismic Reflection Imaging of a Deep‐Penetrating Red River Fault in the Yinggehai Basin, Northwest of the South China Sea

Abstract

AbstractThe Yinggehai Basin (YB) in the northwest of the South China Sea (SCS) has preserved the complete evolution of the Red River Fault (RRF), whose motion over time has largely contributed to shaping the current tectonic framework of the southeastern Tibetan Plateau and Indochina Block. Here we, for the first time, image the RRF, crustal architecture, and crust‐mantle boundary (i.e., Moho) in detail under the YB from two high‐resolution 40‐km‐depth seismic reflection pre‐stack migration profiles. Our seismic reflection images provide direct seismic evidence to support a deep‐penetrating RRF, most likely crosscutting the Moho. In this sense, the RRF was a large‐scale shear zone, along with the clockwise rotation of the Indochina Block, to accommodate the Indochina Block extrusion during Oligocene‐early Miocene and form the YB. We highlight that the material extrusion along deep‐penetrating faults dominated the Tibetan Plateau deformation in response to the India‐Asia collision at an early stage.