Rotated Transtensional Basins Formed During Back‐Arc Spreading in Japan: Simultaneous Rapid Tectonic Rotation and Basin Subsidence

Abstract

Strike-slip basins often develop where strike-slip faulting occurs relative to the plate motion, including at plate boundary transform zones, continental collision zones, and subduction zones. Well-known examples include the San Andreas Fault, the Red River Fault, and the Great Sumatra Fault, respectively. Many studies have classified strike-slip basins based on the geometry of the bounding faults and the kinematic setting of the basin (e.g., Nilsen & Sylvester, 1995), including fault-bend basins (e.g., Ridge Basin, California), stepover basins (e.g., Dead Sea Basin), transrotational basins (e.g., Los Angeles Basin, California), and transpressional basins (e.g., Ventura Basin, California). All of these types of basins develop under strike-slip or transtensional conditions and are subject to variable amounts of rotational strain (Waldron, 2005). However, the development of strike-slip basins has previously been investigated using simplified models, and the effects of basin rotation and the relationship between rotation and basin development have not been well studied. It is only in transrotational basins that tectonic crustal rotation has been considered, and even then basin rotation is usually ignored because transrotational basins are modeled as gaps that form between rotating basement blocks.Along the eastern margin of East Asia, back-arc spreading occurred in several locations during the Cenozoic, including in the Sea of Japan. During the opening of the Sea of Japan, several strike-slip and normal faults developed, resulting in rifting and also the formation of basins (e.g., Jolivet et al., 1994). Dextral strike-slip faults caused back-arc spreading and formed the Sea of Japan (Figure 1) according to the pull-apart basin model that was first proposed by Lallemand and Jolivet (1986). These faults include the Tym Poronaisk Fault and Hidaka