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AOGS 17th Annual Meeting

28 Jun - 4 Jul 2020
Sono Belle Vivaldi Park, Hongcheon

SS04 – The Geologic Evolution of NE Asia

Thu-02 Jul 2020 | 13:30 – 15:30 | Tower B, Lavender II

Moonsup CHO
Chungbuk National University

“Early Paleozoic Linkage of the Korean Peninsula and Proto-Japan Arc with the North China Craton”

Moonsup CHO#+, Wonseok CHEONG, Yoonsup KI

Chungbuk National University


The early Paleozoic paleogeography of East Gondwanan terranes, including the North China Craton (NCC), is contentious, primarily reflecting the paucity of integrated geochronological, biogeographic, and tectonic data sets. Here we introduce new tectono-stratigraphy of the Korean Peninsula typified by the amalgamation of two contrasting terranes, Gyeonggi Marginal Belt (GMB) and Taebaeksan Basin (TB). The GMB is a fold-and-thrust belt composed of metasedimentary units of Neoproterozoic Sangwon Supergroup and Devonian Imjin Group, and affected by Permian medium-pressure metamorphism. The Sangwon Supergroup is unconformably underlain by the NCC basement rocks and characterized by the predominance of Meso- to Neoproterozoic detrital zircons; the Imjin Group, however, exhibits turbiditic lithologies and detrital zircon populations at ~950 and 450 Ma typical for the Qinling Belt. On the other hand, Cambrian–Ordovician platform sequences of the TB contain trilobites of the NCC affinity. Detrital zircons from the sandstones define three types of U-Pb age distributions characterized by: (1) double peaks at ~1.85 and 2.50 Ga diagnostic of the NCC basement; (2) minor peaks at ~1.75, 1.6, and 1.2–1.1 Ga in addition to double peaks; and finally (3) a scattered array of Meso- to Neoproterozoic zircons lacking double peaks. The marked contrasts among the three types reflect significant changes in provenance, most likely linked to variations in paleo-water depths during the ‘Sauk’ transgression. The majority of age spectra also reveal distinct occurrences of youngest populations whose ages gradually decrease up-section from ~510 to 480 Ma. Together with arc-related bulk rock and Nd isotopic compositions, early Paleozoic zircons likely represent the first-cycle detritus supplied from the proto-Japan arc formed at ~520 Ma. Taken together, early Paleozoic Korean margin of the NCC was affected by juvenile magmatism in the proto-Japan arc, perhaps extending from the Terra Australis orogen in the East Gondwana.


Biography


Moonsup Cho has served for 25 years as a professor at the School of Earth and Environmental Sciences, Seoul National University, and is currently a consulting professor at Chungbuk National University, Korea. He was a Visiting Professor at University of Western Australia (2000), Stanford University, U.S.A. (2010), and Kyushu University, Japan (2017). He is a currently a Member of the Korean Academy of Science and Technology, a Fellow of the Geological Society of America, and a Fellow of the Mineralogical Society of America. He has served as Editorial Board member for several international journals, including Lithos, Geological Society of America Bulletin, and Journal of Geological Society, London. He currently serves as Editorial Board member for Journal of Asian Earth Sciences, Geochemical Journal, and Journal of Mineralogical and Petrological Sciences.

His research covers a wide spectrum of topics dealing with the geology and tectonics of various terranes in the Korean Peninsula. In particular, he has contributed to understanding tectono-metamorphic evolution of the peninsula by introducing the sensitive high-resolution ion microprobe (SHRIMP) technique to the Korean geological community. Much of his recent work has focused on detrital zircon geochronology of the Gyeonggi Marginal Belt, encompassing the Ogcheon Metamorphic Belt and Imjingang Belt, Korea. The result is the Qinling–Gyeonggi microcontinent model which well accounts for the correlation among East Asian terranes. Part of this work was recently published as the Pyeongchang Winter Olympic paper in International Geology Review.

 

Organized by:
aogs  aogs
Supported By:
gwcb
Korean Society of Earth and Exploration Geophysicists
The Geological Society of Korea
The Korean Society of Oceanography
Korean Meteorological Society
Korean Society of Atmospheric Environment
The Korean Space Science Society
The Korean Astronomical Society
The Korean Society of Economic and Environmental Geology
The Korean Society of Remote Sensing
The Korean Association of Geographic
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