Abstract

The Seosan-Taean area on the Western Gyeonggi Massif of the Korean Peninsula preserves evidence of multiple geologic events from the Paleoproterozoic to the Early Mesozoic. The purpose of this study is to interpret the structural geometry of the Taean area that can explain the repetition of the Paleoproterozoic Seosan Group in the map. We have conducted structural geometry interpretation of the Taean area based on the various geological field data. Based on the variation in hinge orientations of the map-scale folds, the study area was subdivided into four structural domains (viz., northern, central, southern, and eastern domains). The hinges are plunging to the SW in the northern and southern, to the NE in the central and, to the SSW in the eastern domains. The results indicate the presence of a map-scale NW-vergent asymmetric syncline-anticline pair with NE-SW trending hinges in the northern, central and southern domains. If these results hold up to the eastern domain, the repetition of the Seosan Group in the study area can be attributed to the map-scale asymmetric syncline-anticline-syncline, which might be related to the development of regional faults in the Taean area. Further studies on the structural geometry, kinematics, and associated deformation conditions are required for a better understanding of the structural evolution of the Western Gyeonggi Massif, which will further provide insights into the crustal evolution of the Korean Peninsula since the Paleoproterozoic.

Keywords Western Gyeonggi Massif, Taean area, Seosan Group, Taean Formation, Syncline-anticline-syncline