1992 Fiscal Year Final Research Report Summary
Geological correlation of southwest Japan and Korean Peninsula-tectonics for spreading of active continental margin-.
| Project/Area Number |
02045023
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| Research Category |
Grant-in-Aid for international Scientific Research
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| Allocation Type | Single-year Grants |
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| Section | University-to-University Cooperative Research |
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| Research Institution | Shimane University |
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Principal Investigator |
IIZUMI Shigeru Faculty of Science, Shimane University, 理学部, 教授 (80032639)
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| Co-Investigator(Kenkyū-buntansha) |
KWON Sung Tack College of Science, Yonsei University, 理学部, 助教授
MOON Hi Soo College of Science, Yonsei University, 理学部, 助教授
YU Kang Min College of Science, Yonsei University, 理学部, 副教授
LEE Ha Young College of Science, Yonsei University, 理学部, 教授
ISHIGA Hiroaki Faculty of Science, Shimane University, 理学部, 助教授 (80183002)
AKASAKA Masahide Faculty of Science, Shimane University, 理学部, 助教授 (20202509)
SAWADA Yoshihiro Faculty of Science, Shimane University, 理学部, 助教授 (80196328)
TAKAYASU Katsumi Research center for coastal lagoon environments, Shimane University, 汽水域研究センター, 教授 (00127490)
ITO Haruaki Faculty of Science, Shimane University, 理学部, 教授 (80032423)
TOKUOKA Takao Faculty of Science, Shimane University, 理学部, 教授 (30025358)
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| Project Period (FY) |
1990 – 1992
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| Keywords | Southwest Japan / Korean peninsula / Melange / Granite / Cretaceous / Tertiary / Rb-Sr age / K-Ar age |
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| Research Abstract |
The title of the project is geological correlation of southwest Japan and Korean Peninsula-tectonics for spreading of active continental margin-. Some members of the project visited Yongwol area and examined geologically the Pamuchi melange unit in the Yongwol coal field, and revealed following geologic events ; 1) extensional development of the Late Permian Pamuchi paleo-sea represented by the occurrence of the late Middle to early Late Permian siliceous rocks interbedded with the Lower Permian lagoonal facies limestones, 2) Closure of the Pamuchi basin in Latest Permian to Triassic which resulted to the formation of the Pamuchi melange unit. The latter event coincides significantly to that of the Late Permian Maizuru and Ultra-Tanba Terrains of SW Japan which was investigated in detail on the basis of petrographical data of sandstones. Other members of the project stayed in southeastern part of Korea to do field work for Cretaceous-Miocne igneous and sedimentary rocks. Similar to the granitoid rocks in the San'in Zone, SW Japan, most Cretaceous-Paleogene intrusive rocks in SE Korea are I-type magnetite-series. These rocks show low initial Sr isotope ratios comparable to those in the San'in Belt, SW Japan. Two repesentative plutons show Rb-Sr whole rock isochron ages of 53 and 58 Ma. These data may suggest that the most granitoid rocks in SE Korea are Paleogene in age, and their magmas were derived from similar source materials to those beneath the San'in Belt. Whole rock and hornblende K-Ar age determination revealed that Miocene volcanic rocks have similar ages to those in the San'in district, but the period of the most intensive volcanism was slightly older in SE Korea than in SW Japan. In contrast with San'in district, southwest Japan, volcanism of alkaline rock series initiated in the Cretaceous in SE Korea. This is an important factor to consider magmatic and tectonic evolution of the continental margin accompanied by the opening of Japan Sea.
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