Right‐lateral shear along the Northwest Pacific Margin and the India‐Eurasia Collision

Abstract

Right‐lateral shear along the eastern margin of Asia, from the Eocene to the Present has led to the opening of pull‐apart basins, intracontinental such as the Bohai basin, or oceanic such as the Japan Sea. We suggest in this paper that this right‐lateral shear is a consequence of indentation of Asia by India. As in small‐scale analog experiments, we conclude that antithetic wrench faults accommodate the counterclockwise rotation of large domino blocks between two major left‐lateral shear zones (Tien Shan‐Baikal‐Stanovoy for the northern one, and Qin Ling for the southern one). We discuss the compatibility of this mechanism, which involves a rather small amount of extrusion, with the fast eastward expulsion described for southeast Asia. We re‐emphasize the role played in the opening of marginal basins by the Pacific subduction as a free boundary to the east.