CORRELATION OF UPPER MESOZOIC SEDIMENTARY AND VOLCANOGENIC DEPOSITS OF KOREA AND THEIR DEPOSITIONAL SETTINGS

Abstract

The Upper Mesozoic deposits of the northern and southern parts of the Korean Peninsula significantly differ from each other. The Upper Jurassic-Neocomian deposits of North Korea are represented by the differentiated volcanics and tuffaceous-terrigenous rocks. In the south, they are composed of the discretely distributed continental terrigenous sediments. The upper Hauterivian-middle Albian deposits bear features in common throughout the Korean Peninsula. They are of the continental terrigenous type (with several cycles of sedimentation), and their thickness sharply increases in the southern part of the Korean Peninsula, where, in addition, basaltoids of the intraplate type occur. In North Korea, the upper Albian-Upper Cretaceous deposits are represented by continental terrigenous rocks of a limited distribution range, whereas in South Korea, by a thick volcanogenic-plutonic basic-to-acid rock series. Settings of the Late Mesozoic sedimentation in the Korea-Japan region are reconstructed. In the Late Jurassic-Neocomian, the lateral structural succession included: (1) the North Korean marginal volcanogenic belt, (2) a system of fore-arc troughs (South Korea and Inner zone of Japan), and (3) deep-sea trench (the boundary between Inner and Outer zones of Japan). Subduction setting also existed at the late Albian-Late Cretaceous stage, however the lateral succession of structures (including the Korean-Japanese volcanic belt) was displaced toward the paleo-Pacific. The late Hauterivian-middle Albian period was marked by cessation of subduction, by intense crustal compression in the continental margin, and by formation of intermontane depressions bounded by faults.