On the features of reactivation of the Sino-Korean plate

Abstract

The Sino-Korean plate has undergone strong reactivation, since the Palaeozoic and Mesozoic time in particular. A study of the features of the reactivation is made in accordance with the concept of plate tectonics. Two stages of reactivation are recognized, the Palaeozoic and Meso-Cenozoic reactivations, with an importent turning point taking place in the late Palaeozoic. In the first stage, two mobile belts—running roughly in an E-W direction along the northern and southern peripheries of the ancient Sino-Korean plate—were formed. The variations of some geological features including geochemical ones across these belts show that the occurrence of the mobile belts was precisely controlled by the active continental margins existing at that time. After the late Palaeozoic the direction of the mobile belts changed drastically. The Mesozoic belt consists mainly of the Shandong and Taihang tectonomagmatic zones with tectonic depressions among them, extending in NNE direction. The change in direction of the above mentioned mobile belts is due to the closing of the Mongolian and Qinqi-Dabie palaeo-oceans and because the eastern edge of the Sino-Korean plate became an active continental margin at that time. The authors suggest that there was no so-called automatic activation within the Sino-Korean plate.