1992 Fiscal Year Final Research Report Summary
Comparative study of sedimentary geology and paleomagnetism of the Cretaceous Kanmon Group
| Project/Area Number |
01420012
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| Research Category |
Grant-in-Aid for General Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
地質学一般
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| Research Institution | KYUSHU UNIVERSITY |
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Principal Investigator |
OKADA Hakuyu Kyushu University, Sci.Fac., Professor, 理学部, 教授 (60037182)
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| Co-Investigator(Kenkyū-buntansha) |
HIROOKA Kimio Toyama University, Sci.Fac., Professor, 理学部, 教授 (30029467)
SAKAI Takashi Kyushu University, Sci.Fac., Assistant, 理学部, 助手 (70128023)
MIKI Takashi Kyushu University, Sci.Fac., Assistant, 理学部, 助手 (50037272)
TOMITA Suzuomi Kyushu University, Sci.Fac., Assistant, 理学部, 助手 (20037196)
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| Project Period (FY) |
1989 – 1992
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| Keywords | Kanmon Group / Wakino Subgroup / Lacustrine facies / Red beds / Paleomagnetism / Half-graben structure / Rhythmite / Kyongsang Supergroup |
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| Research Abstract |
(1) Preparation of bibliography All the available literatures related to the Cretaceous Kanmon Group have been collected and compiled as a bibliography. (2) Study of stratigraphy Along some reference geological sections,detailed stratigraphy of the Kanmon Group has been established in the type section of the Miyata area and in the Yamada Park south of Kokura. Detailed geologic map of the Yamada Park area has also been published, presenting a reference lithology of the Wakino Subgroup. (3) Lithofacies analysis Detailed lithofacies analysis was carried out on the Wakino Subgroup,and three major facies of alluvio-fluvial, marginal lacustrine and offshore lacustrine facies were discriminated. In addition, typical rhythmite facies has been recognized in the offshore lacustrine facies. It is further subdivisible into three subfacies of types A,B and C. Origins of each of these types were clarified. (3) Petrologic study of sandstones A comparative study of the sandstones of the Wakino Subgrou
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p with those of the contemporaneous Kyonsang Supergroup in the Korean Peninsula was carried out. The sandstones of the Wakino Subgroup are characterized by a predominance of lithic components such as schist, andesite, slate, etc., whereas the Kyongsang Supergroup are highly feldspathic, containing gneiss and other high-grade meta- morphic rock fragments. The provenance of the Kyongsang Supergroup was Precambrian basement, while that of the Kanmon Group was nearby plutonic rocks and Sangun metamorphic rocks. These facts suggest that the Kanmon and Kyongsang Basins were originally separated. (4) Petrologic study of red beds Red beds characterizing the Kanmon Group were petrologically and geochemically studied, and their origin was discussed in detail. (5) Paleomagnetic study Paleomagnetic analysis of the Kanmon group has clarified that the original site of deposition of the Kanmon Group was at higher latitudes than at present. (6) regional paleotectonics Tectonic significance of the Kanmon Basin was clarified in relation to the half-graben structures in the continental region. Less
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