| Project/Area Number |
62540585
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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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 | Ehime University |
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Principal Investigator |
TAKAHASHI Jiro Faculty of Education, Ehime Univ., Associate Professor, 教育学部, 助教授 (70116945)
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| Co-Investigator(Kenkyū-buntansha) |
KASHIMA Naruhiko Faculty of General Education, Ehime Univ.,Professor, 教養部, 教授 (10036197)
MATSUO Hidekuni Faculty of Science, Ehime Univ., Professor, 理学部, 教授 (20019798)
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| Project Period (FY) |
1987 – 1988
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| Project Status |
Completed (Fiscal Year 1988)
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| Budget Amount *help |
¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 1988: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1987: ¥1,100,000 (Direct Cost: ¥1,100,000)
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| Keywords | Sotoizumi Group / Upper Cretaceous / Western Shikoku / 放散虫化石 / 白亜紀末期の堆積盆 |
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| Research Abstract |
The purpose of this study is to interpret the depositional and geologic structural environments of the Upper Cretaceous in western Shikoku. Results of the field investigation opint to the following conclusions:
1. The so-called Sotoizumi Group is continental shelf sediments which are composed of sandstone, shale and conglomerate, locally with slump beds. 2. The Izumi Group is a marine formation which was deposited in the tectonic basin along the Median Tectonic Line. The deposits are mainly composed of sandstone associated with mudstone, conglomerate and vitric tuff, and are characterized by alternating beds of sandstone and mudstone. 3. The Uwajima Group, which have been generally called the Shimanto Supergroup,consists mainly of sandstone and fossiliferous shale alternatingin various thicknesses and proportions, and is occasionally interbedded with conglomerate and slump beds. This group deposited under the marine conditions which are the continental shelf, teh continental slope and the deep sea plain. 4. The Kikunotani formation in Shirokawa Town once believed to be Early Cretaceous in age is now placed in Middle Jurassic to Rarly Cretaceous as a result of the recent discovery of radiolarians.
Tectonics of Late Cretaceous in western Shikoku is a problem awaiting future solution.
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