비봉-광천지역 변성 화성암류의 암석 성인 및 지구조적 의미

Abstract

The Hongseong area in the southwestern Gyeonggi Massif of the Korean Peninsula consists of Paleoproterozoic, Neoproterozoic, and Paleozoic complexes that were regionally metamorphosed during the Triassic collision between the North and South China blocks. The southern and eastern parts of the area consist mainly of Paleoproterozoic unit including porphyroblastic orthogneiss and banded paragneiss. In contrast, the northwestern part of the area consists of the Early Paleozoic Wolhyeonri unit, the Neoproterozoic Deokjeongri unit and Late Paleozoic Taean unit. The Wolhyeonri unit consists of paragneiss, schist, metavolcanics, impure marble, orthogneiss, and quartzite. The Deokjeongri unit consists of amphibole-bearing orthogneiss, biotite granitic orthogneiss, and leucogranite. The Wolhyeonri unit is overlain unconformably by Taean unit consisting Late Paleozoic low-grade metasediments. The rocks of these unit were intruded by Middle Jurassic granites and were partly covered by Cretaceous volcano-sedimentary rocks. Especially, The Bibong, Baekdong and Gwangcheon from the Hongseong area in the southwestern part of the Gyeonggi Massif, are well known for the lenticular ultramafic and metabasite bodies, which preserve evidence for subduction and collision. The latest study focused on metaigneous rocks including metabasite and metavolcanics in the Bibong, Baekdong, and Gwangcheon areas.