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Pedogenic significance of eolian dust in Japanese soils

日本土壤中风积尘的成土意义

基本信息

批准号：
60560066
负责人：
INOUE Katsuhiro
金额：
$ 1.09万
依托单位：
Iwate University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1985
资助国家：
日本
起止时间：
1985 至 1986
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-60560066/
关键词：
Eolian dust Loess Tephra <^(14)C> age Palaeo-sand dune 種子島喜界島

项目摘要

The results obtained in this study are as follows:1. The parent material and pedogenesis of Red-Yellow soils in Ryukyu Islands: (1) On the basis of their chemical properties, clay mineral composition and oxygen isotopic ratio of fine quartz, Red-Yellow soils on the Kunigami terrace in Okinawa were formed on eolian dust deposits derived from China. (2) Red soils and Yellow soils were, respectively, formed on the eolian dust deposits at the interglacial ages and the glacial ages. (3) The dithionite soluble iron ( <Fe_d> ), acid oxalate soluble iron ( <Fe_o> ) and total iron ( <Fe_t> ) of Red-Yellow soils in Ryukyu Islands were determined. By using a relationship between the <Fe_o> / <Fe_d> ratio and the ( <Fe_d> - <Fe_o> )/ <Fe_t> ratio, Red soils were clearly distinguished from Yellow soils.2. Tephra and eolian dust deposits in Tanegashima: (1) The stratigraphy of the Jyusanban profile in Tanegashima was identified. Tephra and eolian dust layers in the profile were isolated by determining the phosphate retention, pH(NaF) value, amounts of acid oxalate soluble Al and predominant clay minerals. (2) By using the marker-tephra layers (Ah and AT ashes), which their ages of eruption were already known, the rate of dust deposition in the last glacial age is estimated to be about 7-8.7 g/ <cm^2> /1,000 years in Tanegashima. 3. From <^(14)C> ages and chemical and clay mineralogical properties of eolianites in Kikai, it is estimated that the eolian dust deposition was marked at the last glacial age.

本研究取得的结果如下： 1．琉球群岛红黄土的母质和成土作用：（1）根据其化学性质、粘土矿物成分和细石英的氧同位素比，冲绳国头台地的红黄土是由来自中国的风成尘沉积物形成的。 (2)间冰期和冰河期的风尘沉积物上分别形成红土和黄土。 (3)测定了琉球群岛红黄色土壤的连二亚硫酸盐可溶性铁(<Fe_d>)、酸性草酸盐可溶性铁(<Fe_o>)和全铁(<Fe_t>)。利用<Fe_o>/<Fe_d>比值和(<Fe_d>-<Fe_o>)/<Fe_t>比值之间的关系，可以清楚地区分红土和黄土。2．种子岛的火山灰和风成尘沉积物：（1）识别了种子岛十三板剖面的地层。通过测定磷酸盐保留量、pH(NaF) 值、酸性草酸盐可溶性铝和主要粘土矿物的量，分离剖面中的火山灰和风积尘层。 (2) 利用喷发年龄已知的标记火山灰层（Ah 和 AT 灰烬），估计种子岛末次冰期的尘埃沉积率约为 7-8.7 g/ <cm^2> /1,000 年。 3. 根据Kikii地区风成岩的<^(14)C>年龄以及化学和粘土矿物学性质，估计风成尘沉积在末次冰河时代很明显。