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Geological Structures of the Taean Formation in the Gomseom Area, Southwestern Gyeonggi Massif
경기육괴 남서부 곰섬 일대 태안층의 지질구조
Econ. Environ. Geol. 2019 Apr;52(2):159-68
Published online April 30, 2019;  https://doi.org/10.9719/EEG.2019.52.2.159
Copyright © 2019 the Korean society of economic and environmental gelology.

Inho Kim, Ae-Ji Kim, Hayoung Woo and Seung-Ik Park*
김인호 ·김애지 ·우하영 ·박승익*

Department of Geology, School of Earth System Science, Kyungpook National University, Daegu 41566, Republic of Korea
경북대학교 지구시스템과학부 지질학전공
Received April 3, 2019; Revised April 26, 2019; Accepted April 27, 2019.
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
 Abstract
The western Gyeonggi Massif, where records evidence of Phanerozoic subduction/collision tectonics, is an important area to understand the crustal evolutionary history of the Korean Peninsula. This study presents geometric and kinematic characteristics of the geological structures of the Taean Formation in the Gomseom area, southwestern Gyeonggi Massif. We interpreted the geometric relationships between structural elements, and conducted stereographic and down-plunge projections for structural domains. As a result, at least three different deformational events (D1, D2 and D3) are recognized in the study area. In the first deformational event (D1), regional foliations being well defined by the preferred orientation of muscovite and biotite were formed. In the second deformational event (D2), NNE-trending low-angle contractional faults and related crenulation lineations/cleavages were formed. The crenulation lineations shallowly plunge toward SSW~SSE or NNW~NNE. In the third deformational event (D3), SE-plunging folds and NE-trending high-angle faults were formed as ‘fault-related fold’ and ‘fold-accommodation fault’, indicating that the D3 folds and faults are genetically linked to each other. This contribution provides important insights into the structural evolution of the Taean Formation along western Gyeonggi Massif, where had evolved as subduction/collisional orogenic belts in the East Asia.
Keywords : Gyeonggi Massif, Taean Formation, deformation sequence, fault-related fold, fold-accommodation Fault

 

June 2019, 52 (3)