Geology of the 2018 Winter Olympic site,Pyeongchang, Korea |
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| Authors: | Moonsup Cho Kyoungwon Min Hyeoncheol Kim |
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| Institution: | 1. Department of Earth and Environmental Sciences, Chungbuk National University, Cheongju, Korea;2. Department of Geological Sciences, University of Florida, Gainesville, FL, USA;3. Geology Division, Korea Institute of Geoscience and Mineral Resources, Daejeon, Korea |
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| Abstract: | We review the geology of the Gyeonggi Massif, Gyeonggi Marginal Belt, and Taebaeksan Basin of the Korean Peninsula, which are relevant to the 2018 Winter Olympic sites. Neoarchaean–Palaeoproterozoic gneisses and schists of the Gyeonggi Massif underwent two distinct collisional orogenies at the Palaeoproterozoic (1.88–1.85 Ga) and Triassic (245–230 Ma). These basement rocks are structurally overlain by a suite of Mesoproterozoic to Early Permian supracrustal rocks of the Gyeonggi Marginal Belt, consisting primarily of medium-pressure schists and amphibolites metamorphosed at ~270–250 Ma. In contrast, sedimentary successions in the Taebaeksan Basin, commonly fossiliferous, consist primarily of Early Cambrian–Middle Ordovician Joseon Supergroup and Late Carboniferous–Early Triassic Pyeongan Supergroup. The ‘Great Hiatus’ between the two supergroups is characteristic for the North China Craton. The marked contrast in tectonometamorphic evolution between the Taebaeksan Basin and Gyeonggi Marginal Belt suggests an existence of major suture in-between, which is most likely produced by the Permian–Triassic continental collision between the North and South China cratons. Finally, recent tectonics of the Korean Peninsula is governed by the opening of East Sea/Sea of Japan during the Late Oligocene–Early Miocene. This back-arc rifting event has resulted in an exhumation of the Taebaek Mountain Range, estimated to be 22 ± 3 Ma on the basis of apatite (U–Th)/He ages. Thus, high topography in the 2018 Winter Olympic sites is the consequence of Tertiary tectonics associated with the opening of a back-arc basin. |
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| Keywords: | Pyeongchang 2018 Winter Olympic Permian–Triassic orogeny Oligocene–Miocene uplift Gyeonggi Massif Gyeonggi Marginal Belt Taebaeksan Basin Korean Peninsula North China Craton |
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