| Budget Amount *help |
¥3,200,000 (Direct Cost: ¥3,200,000)
Fiscal Year 2005: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 2004: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 2003: ¥1,100,000 (Direct Cost: ¥1,100,000)
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| Research Abstract |
In the research periods of three years, Okinawa, Hosoike moor and Kurayoshi were investigated. Okinawa Island is the southern limit of eolian dust transported by westerly winds from the Asian Inland deserts. The Hosoike in the Chugoku Mountains in Okayama Prefecture and Kurayoshi in Tottori Pref. are the northern limits of eolian dust from Asian Inland deserts distributed during the ice ages. Eolian dust in the mid-west of Korea was transported,from the northern Precambrian rock regions by winter north-westerly winds during the ice ages. In addition to three areas, loess samples from Hokkaido, Fukui and northeastern China were analyzed in the comparative study.
1)Eolian dust from Taklamakan and the Gobi deserts have been transported to Okinawa along a middle latitude course by the sub-tropical summer jet stream since MIS 10. A large portion of the parent material in the Red-Yellow soils consists of eolian dust.
2) In the Hosoike moor, fluvial material deposition prevailed during the warm
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er Interstadials, while, eolian dust deposition prevailed during the cold periods since 30,000 years BP. Eolian dust was brought from the northern Precambrian rock regions by the winter northwesterly winds during glacial periods, while, eolian dust was transported from the Chinese Inland deserts by the summer jet stream in MIS 1.
3)In Kuroyashi, loam layers have been deposited between tephras since 300 ka. Judging from ESR oxygen vacancy, most of the silt-sized quartz in loam layers is considered to be eolian dust.
4)Korean loess in mid-western Korea from MIS 10 consists of mixed material consisting of both eolian dust from the northern Asian continent and from the dried sea floor of the Yellow Sea deposited during glacial periods.
5)Judging from ESR high oxygen vacancies, the eolian dust in Hokkaido and that in Fukui were transported from the northern Asian continent during glacial periods. In northeastern China, eolian dust increased through anthropogenic vegetation changes since the 14th century. Less
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