| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 2001: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 2000: ¥1,100,000 (Direct Cost: ¥1,100,000)
|
|---|
| Research Abstract |
I collected the four drilling cores of peat deposited since the last Interglacial period from Nayoro basin in Hokkaido, Yanohara moor in Fukushima Prefecture, Nakaikemi baisin in Fukui Prefecture and Kuroi basin in Hyogo Prefecture in Japan. In addition to those areas, I collected two drilling cores of peat and clay deposited since the last glacial period from Tanigumi moor in Gifu Prefecture and Cheju Island in Korea. Six cores show following climatic features as inferred from eolian dust analysis: climatic changes, wind direction, and the location of polar front in East Asia since the last Interglacial period.
Summer monsoon was predominantly and fluvial material deposited in the basins and moor by the increased summer rain during MIS 5 and MIS 1. As the polar front shifted to the North Hokkaido, eolian dust was transported from the inland desert areas in China by westerlies. In the last glacial period, the polar front migrated to the Seto Inland Sea. Eolian dust was transported from the Precambrian rock areas and the emerged sea floor by the NW winter monsoon between Hokkaido and the Seto Inland Sea. In Interstadials 24 to 1 during the last glacial period, fluvial material deposited. On the other hand, eolian dust deposition increased in the cold periods such as Heinrich events. The median diameter of eolian dust fluctuated with a saw-tooth shape provoked by the gradual glaciation and abrupt deglaciation during the last glacial period. After 14 ka, eolian dust deposition decreased, and median diameter of fluvial material increased. Obtained pattern is in agreement with the general correspondence between dust deposition and climatic changes. Eolian dust record from six cores showed trends also seen in dust records from polar regions.
|
