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Changes of dust flux and paleo-environments during the Last Glacial Age in Japanese Islands.

日本列岛末次冰期沙尘通量与古环境的变化。

基本信息

批准号：
06680161
负责人：
NARUSE Toshiro
金额：
$ 1.34万
依托单位：
HYOGO UNIVERSITY OF TEACHER EDUCATION
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-06680161/
关键词：
eolian dust dust flux loess paleosols last glacila age ESR 広域風成塵日本列島

项目摘要

1. Eolian dust flux increased during the last Glacial age more than that of the Holocene. The increases of dust flux in both stages 2 and 4 during the last Glacial age suggests an enforcement of prevailing wind and monsoon during two stages. A bigger dust flux in the stage 2 than stage 4 reflects (1) stronger westerlies and winter monsoon, and (2) a wider emergence of continental shelf which becomes an important dust source.2. Electron spin resonance (ESR) spectra of fine quartz grains less than 20 micro-meter have been measured to identify the source areas of eolian dust. Fifty-nine samples of loess, soils, paleosols and bore cores from China, Korea and Japan were measured. ESR signal intensity of eolian dust quartz is a useful tracer for the provenance of the quartz.3. The measurement values (in arbitrary unit) of eolian dust fine quartz of stage 2 in China and Korea were as follows ; Taklamakan and Quidam : 6.2 to 8.2, Upper Malan loess : 5.8 to 8.3, Korean soils : 6.0 to 7.7. The quartz of Chinese loess and Korean soils are remarkably similar to ranges of ESR intense signal. This similarity is attributed to their common eolian origin from the arid and semi-arid Asian continental areas during the isotope stage 2.4. Japanese Islands are divided into three areas from the view point of ESR spectra of fine quartz. (1) Yonaguni Island soil quartz was 9.8 originated in the Precambrian rock area of southern Asian continent. (2) Soil quartz from Okinawa to Fukui were 5.8 to 8.5 which coinsided with those of Chinese loess. It shows that eolian dust was brought from the Asian arid and semi-arid areas such as Tibetan Plateau. Taklamakan and Gobi deserts etc (3) Soil quartz from Aomori to Hokkaido were more than 10, originated in the Precambrian rock area of north Asian continent.Fine quartz of three areas were brought from the Asian continent by the prevailing winds of several ways in the stage 2.

1. 末次冰期的风尘通量增加幅度大于全新世。末次冰期期间第 2 阶段和第 4 阶段沙尘通量的增加表明这两个阶段期间盛行风和季风的加强。第2阶段沙尘通量大于第4阶段，反映了（1）西风和冬季风更强，（2）大陆架出现范围更广，成为重要的沙尘源。2．测量了小于 20 微米的细石英颗粒的电子自旋共振 (ESR) 光谱，以确定风成尘的来源区域。对来自中国、韩国和日本的 59 个黄土、土壤、古土壤和岩心样品进行了测量。风成尘石英的ESR信号强度可作为石英来源的有效示踪剂。 3．中国和韩国第二阶段风尘细石英的测量值（任意单位）如下；塔克拉玛干和奎达姆：6.2至8.2，马兰上部黄土：5.8至8.3，朝鲜土壤：6.0至7.7。中国黄土和韩国土壤的石英与ESR强信号范围非常相似。这种相似性归因于它们共同的风成起源于同位素阶段 2.4 的干旱和半干旱亚洲大陆地区。从细石英的ESR光谱的角度来看，日本列岛分为三个区域。（1）与那国岛土壤石英为9.8，产于南亚大陆前寒武纪岩石区。 (2)冲绳至福井的土壤石英含量为5.8～8.5，与中国黄土的石英含量一致。这说明风尘是从青藏高原等亚洲干旱、半干旱地区带来的。塔克拉玛干、戈壁沙漠等 (3) 青森至北海道土壤石英 10 余种，产于北亚大陆前寒武纪岩石区。其中 3 个地区的细粒石英是由第二阶段多路盛行风从亚洲大陆带来的。