Reconstruction of monsoon in western part of Japan since the last Interglacial age viewed from eolian dust

在为期三年的研究期间，对冲绳、细池沼地和仓良进行了调查。冲绳岛是由亚洲内陆沙漠的西风带来的风沙的南部边界。冈山县Chugoku山脉的细池和鸟取县的Kurayoshi是亚洲内陆沙漠在冰河时期形成的风沙的北部边界。韩国中西部的风沙是在冰河时期被冬季西北风从北部的前寒武纪岩石区吹来的。除3个地区外，还对北海道、福井和中国东北地区的黄土样本进行了比较研究。(1)自MIS 10以来，塔克拉玛干和戈壁沙漠风沙被亚热带夏季急流沿中纬度路线输送到冲绳。红黄土的母质中有很大一部分是风沙。(2)细池沼泽在温暖期以河流物质沉积为主，而在寒冷期以风沙沉积为主。风成沙尘主要是冰期冬季西北风从北部前寒武纪岩石区吹来的，而中国内陆沙漠的风成沙尘主要是由MIS 1.3夏季急流吹来的。从ESR氧空位判断，壤土层中粉砂级石英大部分为风成尘。(4) MIS 10在韩国中西部的朝鲜黄土是由北亚大陆风沙和黄海干燥海底在冰期沉积的混合物质组成的。5)从ESR高氧空位判断，北海道风沙和福井风沙是冰期从北亚大陆运来的。14世纪以来，中国东北地区的风沙因人为植被变化而增加。少

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 … More 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