Collisional orogene between north and south China and its eastern extension in the Korean Peninsula

Abstract

The relative movement between the north China block (Sino-Korean craton) and the south China block (Yangtze-Cathaysian craton) had been right-lateral along a transform fault during the Late Paleozoic. Devonian deep-water deposits on oceanic crust existed only in the east Qinling and Tongbuo areas where subduction of ocean crust is evidenced by metamorphism, magmatism and deformation. Carboniferous and Permian clastics and minor carbonates of shallow marine and terrestrial facies were deposited in a series of narrow basins with general east-west trending, and were controlled by the transform fault. The biota of the basins were communicated with the contemporary sedimentary basins in south China, north China and west China. There has been no wide Mesozoic oceanic crust between the north and south China blocks. Tectonic framework of central China during the Late Paleozoic is quite similar to that of western North America during the Cenozoic. Amalgamation of Sino-Korean craton with Siberian craton at the end of Paleozoic changed the moving direction of the former to the southeast and contraction was prevailing between the already juxtaposed north and south China blocks and the intervening Dabie-Su-Lu microcontinent. The southeast corner of north China block was slipped into the concave of the microcontinent, and enabled the latter to be underthrusted to a depth of more than 80 km to form a ultra-high pressure metamorphic complex in Early and Middle Triassic time. Down-going oceanic crust is not a prerequisite of A-type subduction such as the case in Pamir. The Tan-Lu fault, primarily a hinge fault, took place at the climax of contraction between north and south China blocks in the Late Triassic. Differential uplifting and the consequent erosion of Dobie and Su-Lu terranes, which are constituted by piles of subhorizontal thrust sheets, led to an apparent left-lateral offset. Su-Lu was uplifted higher and unroofed deeper than Dabie. An ancient river system along the east-west trending suture had been drained off into Songpan-Ganzi ocean to the west. Collision of the Indian plate with the Eurasian plate shifted the relative movement between the north and south China blocks to the left-lateral and initiated the Fen-Wei graben since Paleogene. The Imjingang belt between North and South Korea connects to the suture zone in the Dabie-Su-Lu area. To the east, an active continental margin along the southern margin of the Hida belt of Japanese islands prevailed in the Late Paleozoic. The Ogcheon belt in South Korea is an Early Paleozoic rift zone which is the extension of the Huanan aulacogen in south China. The Gyeonggi and Ryeongnam massifs of South Korea recorrelated to Yangtze and Cathaysian massifs in the mainland of China.