North and South China suturing in the east end: What happened in Korean Peninsula?

Abstract

The history of basin formation and crustal deformation of the Korean Peninsula is here critically reviewed to show it is an important tectonic architecture of the collision between North and South China in Early Mesozoic. To synthesize our current geologic and paleomagnetic knowledge, we propose a new crustal detachment and extrusion model for the continental collision and rotation between the North and South China Blocks (NCB and SCB) east of the Tancheng–Lujiang fault. We emphasize that the Yellow Sea Transform Fault (YSTF) played a key role in accommodating the collisional history of the two blocks in the east end. The YSTF allowed the Korean Peninsula exempted from being directly involved in the NCB–SCB collision. During the Early Triassic collision phase of the two blocks, a large piece of the upper crust of the northeastern part of the SCB was detached and slumped over the Korean Peninsula and fragmentally deposited in the metamorphosed Okcheon Trough. In the course of the exhumation of the Sulu ultra-high-pressure (UHP) metamorphic belt in the Middle Triassic, the northern part of the SCB extruded eastward toward Korea. A general time correlation of the Songnim orogeny of Korea and the early exhumation of the Sulu UHP metamorphic belt suggests their genetic relation. The exhumation of the Sulu UHP metamorphic belt triggered the mid Triassic extrusion tectonics, which in turn facilitated the clockwise rotation of the SCB. The eastward extrusion and clockwise rotation of the SCB (relative to NCB) exerted a large amount of eastward compression to the Korean Peninsula and led to the Middle–Late Triassic Songnim orogeny. Geologic and paleomagnetic information synthesized in this paper has revived and reinforced the belief for the single Sino-Korean Craton which comprises Korea and north China since the Precambrian time.