[런천세미나] 지구환경과학부 구성원을 위한 특별강연(2)-최덕근 명예교수
일시 : 2022-01-24(월) 13:30 ~ 15:30
연사 : 최 덕 근 명예교수
소속 : 지구환경과학부
문의 : 02-880-6724
장소 : 온라인(zoom)
온라인(zoom) 주소: https://snu-ac-kr.zoom.us/j/86101696824
판구조론으로 본 한반도 형성과정
(Assembling the Korean Peninsula)
최 덕 근 (Choi, D.K.)
The Korean Peninsula is known to have been formed by tectonic processes involving assembly of the Sino-Korean Land (SKL) and South China Land (SCL) in the Triassic. This presentation focuses on sedimentation and tectonic evolution of the Korean Peninsula during the Neoproterozoic and Paleozoic, tectonically most dynamic period in the geologic history of the peninsula. The peninsula is tectonically divided into the northern, central, and southern blocks, which are further subdivided into eleven tectonic provinces. Prior to the Mesozoic, the northern and southern blocks belonged to the SKL, while the central block to the SCL. The so-called Okcheon Belt is treated as a tectonic collage formed by amalgamation of two sedimentary basins with different origins, i.e., the Chungcheong Basin and Taebaeksan Basin. The Chungcheong and Taebaeksan basins belonged to the SCL and SKL, respectively, until they merged to form the Okcheon Belt in the Triassic.
The Chungcheong Basin was the site for the Okcheon Supergroup, which is a Neoproterozoic sedimentary succession of volcanic, glaciogenic, siliciclastic, and carbonate rocks. The Chungcheong Basin was suggested a part of an intracratonic rift basin, the Nanhua Basin of the SCL, in the Neoproterozoic. Two volcanic successions were accumulated during rifting stages and constitute the lower part of the Okcheon Supergroup. These are succeeded by a thick sequence of glaciogenic diamictites representing the Cryogenian global snowball Earth event and the immediately overlying cap carbonate bed recorded deglaciation. This was followed by deposition of dark gray slate/phyllite facies and carbonate facies in a warm and poorly oxygenated basin. The Taebaeksan Basin comprises the Cambrian-Ordovician Joseon Supergroup and the Carboniferous-Permian Pyeongan Supergroup, which are separated by a disconformity representing a ~140-myr-long hiatus. The Joseon Supergroup is a mixed siliciclastic-carbonate succession deposited in an epeiric sea, Joseon Sea, in the early Paleozoic. Early Paleozoic sedimentation commenced at ~520 Ma with global sea-level rise and terminated at ~460 Ma presumably due to uplift of the Joseon Sea in the process of breakup of the SKC from Gondwana. Sedimentation in the Taebaeksan Basin resumed in the late Paleozoic and formed a thick siliciclastic succession, Pyeongan Supergroup, which consists of marginal marine and non-marine alluvial deposits. The depositional setting of the Pyeongan Supergroup was a retroarc foreland basin formed by buildup of a magmatic arc, Inner Mongolia Paleo-uplift, along the northern margin of the SKL. Late Paleozoic sedimentation ceased at ~250 Ma due to the collision of the SKC and SCL along the Sulu-Imjingang Belt.
A number of tectonic models have been proposed for the Permian-Triassic assembly of the Korean Peninsula, but the indented wedge model is considered to best explain the geological features of the peninsula. The indented wedge model warrants northward subduction of the central block (part of the SCL) beneath the northern block (part of the SKL) along the Sulu-Imjingang Belt in the Triassic. It is proposed that the Imjingang Belt and the Gyeonggi Massif represent parts of an accretionary wedge formed by continental plate subduction of the SCL beneath the SKL. The long-lasting interplay of tectonics and sedimentation of the northern, central, and southern blocks, while traveling from Rodinia to Pangea, ended up with formation of the proto-Korean Peninsula in the Triassic.
판구조론으로 본 한반도 형성과정
(Assembling the Korean Peninsula)
최 덕 근 (Choi, D.K.)
The Korean Peninsula is known to have been formed by tectonic processes involving assembly of the Sino-Korean Land (SKL) and South China Land (SCL) in the Triassic. This presentation focuses on sedimentation and tectonic evolution of the Korean Peninsula during the Neoproterozoic and Paleozoic, tectonically most dynamic period in the geologic history of the peninsula. The peninsula is tectonically divided into the northern, central, and southern blocks, which are further subdivided into eleven tectonic provinces. Prior to the Mesozoic, the northern and southern blocks belonged to the SKL, while the central block to the SCL. The so-called Okcheon Belt is treated as a tectonic collage formed by amalgamation of two sedimentary basins with different origins, i.e., the Chungcheong Basin and Taebaeksan Basin. The Chungcheong and Taebaeksan basins belonged to the SCL and SKL, respectively, until they merged to form the Okcheon Belt in the Triassic.
The Chungcheong Basin was the site for the Okcheon Supergroup, which is a Neoproterozoic sedimentary succession of volcanic, glaciogenic, siliciclastic, and carbonate rocks. The Chungcheong Basin was suggested a part of an intracratonic rift basin, the Nanhua Basin of the SCL, in the Neoproterozoic. Two volcanic successions were accumulated during rifting stages and constitute the lower part of the Okcheon Supergroup. These are succeeded by a thick sequence of glaciogenic diamictites representing the Cryogenian global snowball Earth event and the immediately overlying cap carbonate bed recorded deglaciation. This was followed by deposition of dark gray slate/phyllite facies and carbonate facies in a warm and poorly oxygenated basin. The Taebaeksan Basin comprises the Cambrian-Ordovician Joseon Supergroup and the Carboniferous-Permian Pyeongan Supergroup, which are separated by a disconformity representing a ~140-myr-long hiatus. The Joseon Supergroup is a mixed siliciclastic-carbonate succession deposited in an epeiric sea, Joseon Sea, in the early Paleozoic. Early Paleozoic sedimentation commenced at ~520 Ma with global sea-level rise and terminated at ~460 Ma presumably due to uplift of the Joseon Sea in the process of breakup of the SKC from Gondwana. Sedimentation in the Taebaeksan Basin resumed in the late Paleozoic and formed a thick siliciclastic succession, Pyeongan Supergroup, which consists of marginal marine and non-marine alluvial deposits. The depositional setting of the Pyeongan Supergroup was a retroarc foreland basin formed by buildup of a magmatic arc, Inner Mongolia Paleo-uplift, along the northern margin of the SKL. Late Paleozoic sedimentation ceased at ~250 Ma due to the collision of the SKC and SCL along the Sulu-Imjingang Belt.
A number of tectonic models have been proposed for the Permian-Triassic assembly of the Korean Peninsula, but the indented wedge model is considered to best explain the geological features of the peninsula. The indented wedge model warrants northward subduction of the central block (part of the SCL) beneath the northern block (part of the SKL) along the Sulu-Imjingang Belt in the Triassic. It is proposed that the Imjingang Belt and the Gyeonggi Massif represent parts of an accretionary wedge formed by continental plate subduction of the SCL beneath the SKL. The long-lasting interplay of tectonics and sedimentation of the northern, central, and southern blocks, while traveling from Rodinia to Pangea, ended up with formation of the proto-Korean Peninsula in the Triassic.
