全新世浑善达克沙地粒度旋回及其反映的气候变化  

Climate Changes Revealed by Grain-size Cycles of Holocene in Hunshandake Desert

作　　者：张洪[1] 靳鹤龄[1] 苏志珠[1] 孙忠[1] 

机构地区：[1]中国科学院寒区旱区环境与工程研究所,甘肃兰州730000

出　　处：《中国沙漠》2005年第1期1-7,共7页Journal of Desert Research

基　　金：国家重点基础研究发展规划--中国北方沙漠化过程及其防治研究(TG2000048701);中国博士后科学基金(200303440)共同资助

摘　　要：利用浑善达克沙地北部锡林浩特风成砂/古土壤剖面的粗颗粒含量、标准偏差、中值粒径、平均粒径和粘粒含量等气候代用指标,对浑善达克沙地10ka以来的沉积物粒度进行了系统分析研究。结果表明气候变化存在4个阶段:10 7～9 6kaBP气候相对干冷;9 6～6kaBP气候温暖湿润;6～3 4kaBP气候干冷暖湿波动频繁;3 4kaBP以来气候以干旱为主。The Hunshandake desert is located in the west of Inner Mongolia, China. This region is sensitive to climate change with annual temperature between 0\^9～5\^5℃ and annual precipitation between 240\^3～422\^6 mm. The samples were gotten at 5-cm intervals in the Xilinhaote section(43°52′36\^6″N, 116°05′34\^1″E)which is 2\^8 m high and lies in the Hunshandake desert. In the laboratory the character of the grain-size composition and the changes of the grain-size parameters were analyzed. The relationships of the indicators of monsoon like M_(z) (mean particle diameter), M_(d) (median size), D/SC (the ratio of the coarse sands to the sum of fine sands and clay), the coarse sands fraction(>63 μm), σ_(1) (standard deviation) and the clay fraction(<2 μm) with the monsoon variables were analyzed. The winter monsoon becomes strong when M_(z), M_(d) and the clay fraction become low, but D/SC and σ_(1) become high; on the contrary, the summer monsoon becomes strong when M_(z), M_(d) and the clay fraction become high, but D/SC and σ_(1) become low.\;According to the relationships, the climate changes since 10 ka BP could be divided into 4 stages: 10\^7～9\^6 cal ka BP, cold and arid; 9\^6～6 cal ka BP, warm and humid; 6～3\^4 cal ka BP, fluctuated between cold/arid and warm/humid; 3\^4 cal ka BP to present, arid predominated. The climate changes in the Hunshandake desert are similar with other regions in China and in the world. It is mainly affected by the winter monsoon and the summer monsoon.

关 键 词：气候变化 全新世 气候代用指标 浑善达克沙地 古土壤 沉积物粒度 风成砂 锡林浩特 干旱 北部 

分 类 号：P532[天文地球—古生物学与地层学] P467[天文地球—地质学]