2001 Fiscal Year Final Research Report Summary
Integrated studies on Himalayan uplift and climatic changes - A case of Kathmandu Nappe
| Project/Area Number |
11691112
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 海外学術 |
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| Research Field |
Geology
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| Research Institution | HOKKAIDO UNIVERSITY |
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Principal Investigator |
ARITA Kazunori Hokkaido Univ., Grad. School of Sci., Asso. Prof., 大学院・理学研究科, 助教授 (30091408)
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| Co-Investigator(Kenkyū-buntansha) |
SAKAI Tetsuya Kyoto Univ, Grad, School of Sci., Assis. Prof., 大学院・理学研究科, 助手 (90303809)
TAKAGI Hideo Waseda Univ., Fac. of Education, Prof., 教育学部, 教授 (60154754)
WATANABE Teiji Hokkaido Univ., Grad. School of Earth Environmental Sci., Asso. Prof., 大学院・地球環境科学研究科, 助教授 (40240501)
SAKAI Harutaka Kyushu Univ. Grad. School of Social and Cultural Studies, Prof., 大学院・比較社会文化研究科, 教授 (90183045)
KIMURA Kazuo Naruto Univ. of Edu., Dept of Social Science Edu. Assis. Prof., 学校教育学部, 助手 (80314889)
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| Project Period (FY) |
1999 – 2001
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| Keywords | Nepal / Himalaya / moutain uplift / Asian monsoon / lake deposits / climatic changes / Paleo-Kathmandu lake / magnetostratigraphy |
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| Research Abstract |
We studied uplift processes and the resultant climatic and environmental changes since the Late Miocene in central Nepal including the Kathmandu basin, which is located on the Kathmandu Nappe and is archives of paleoclimate in the Himalaya, from interdisciplinay viewpoints such as geology, sedimentology, magnetostratigraphy, pollen and diatom analyzes, geomorphology and glaciology.
Main results are as follows:
1. Kathmandu Nappe consists of a single thrust sheet. It is edged by the underlying Main Central Thrust zone and cut on the north by an out-of-sequence thrust which has resulted in the rapid uplift since the latest Miocene of the Higher Himalaya to the north.
2. The Main Central Thrust zone has been a normal fault in brittle condition since 3 Ma, although it has been thrust zone in ductile condition until 9 〜 6Ma.
3.The stratigraphy of the upper Pliocene to Pleistocene Paleo-Kathmandu lake deposits has been established and the vertical and lateral changes of their sedimentary fades have been elucidated. But it is still unsolved whether the changes has been caused by mountain uplift or by fluctuation of water-level due to climatic changes.
4. The changes of the sedimentary environment and paleoclimate in the Kathmandu basin has been made clear.
5. The pollen analysis shows that the Kathmandu area has been cooler and more dry than the present around 25 ka.
6. The Paloe-Kathmandu lake has been the largest with a maximum shore-level upto 1440 m above sea level around 30 ka and then has been gradually reduced.
7. The temperature at the Last glacial maximum in the Sub-Himalaya to the south of Kathmandu was 7-8℃ lower and more dry than the present. Thereafter it has been gradually warm with cyclic humid climate and became to the present climate around 5 ka.
8. Three borings upto 221 m, 65 m and 5 m depth were performed in the Kathmandu basin.
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[Publications] Sakai, H., Fujii, R., Kuwahara, Y., Upreti, B.N., Shrestha, S. D.: "Core drilling of the basin-fill sediments in the Kathmandu Valley for palaeo-clmatic study: preliminary results"Journal of Nepal Geological Society, special issue. 25. 9-18 (2001)
Description
「研究成果報告書概要(欧文)」より
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[Publications] Takagi, H., Sawaguchi, T., Arita, K., Kobayashi, K., Awaji, D.: "Shear movement of the MCT zone In the Langtang Valley, central Nepal"Monthly Chikyu. 24. 241-249 (2002)
Description
「研究成果報告書概要(欧文)」より
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