150 ka B.P.以来萨拉乌苏河流域主元素变动旋回  

The change cycles of major element in Salawusu River valley since 150 ka B.P.

作　　者：李后信[1] 李保生[1] 祝一志[2] 靳鹤龄[3] David Dian ZHANG 阎满存[5] 张宇红[1] 罗开利[1] 姚春霞[1] 

机构地区：[1]华南师范大学地理系,广东广州510631 [2]中国科学院地球环境研究所黄土与第四纪地质国家重点实验室,陕西西安710061 [3]中国科学院寒区旱区环境与工程研究所,甘肃兰州730000 [4]香港大学地理与地质学系 [5]清华大学水利水电工程系,北京100084

出　　处：《地球化学》2002年第5期424-432,共9页Geochimica

基　　金：国家自然科学基金(49971009);中国科学院地球环境研究所黄土与第四纪地质国家重点实验室资助项目(SKLLQG0008);国家重点基础研究发展规划资助项目(G2000048701)

摘　　要：萨拉乌苏河流域米浪沟湾剖面150kaB.P.以来存在27个由风成砂与河湖相和古土壤构成的沉积旋回。通常后两者的Al2O3、TFe、Mn、TiO2、K2O、MgO、CaO和Na2O含量明显高于前者,而SiO2则相反,构成了与沉积旋回相应的150kaB.P.以来27个元素变化旋回。结合各元素的化学迁移特性、研究区所在的鄂尔多斯高原东南部洼地地貌特征以及季风沙区位置,论证了风成砂中SiO2含量增高,Al2O3、TFe、Mn、TiO2、K2O、MgO、CaO和Na2O相对降低,与干寒多风气候及其影响下石英的大量迁入有关,而河湖相和古土壤中SiO2相对迁移、Al2O3等呈聚集的势态,与暖湿气候作用下稳定性元素Al2O3、TFe、Mn、TiO2和非稳定性元素K2O、MgO、CaO、Na2O都能够从四周地表汇集于本区这种特殊的比较封闭的低地有关。研究表明,萨拉乌苏河流域150kaB.P.以来27个元素变化旋回与该时期北半球冰期-间冰期气候波动诱发的亚洲冬夏季风在毛乌素沙漠的多次更迭具有成因上的联系。There are 27 sedimentary cycles that are made up of aeolian facies and fluviolacustrine facies or palaeosol in Milanggouwan section in Salawusu River valley. The contents of Al2O3, TFe, Mn, TiO2, K2O, MgO, CaO and Na2O in the later two are higher than those in the former, and the contents of SiO2 take on converse change. It constitutes 27 element change cycles corresponding with above mentioned sedimentary cycles since 150 ka B.P. Based on the chemical migrating peculiarity of each element and the geomorphological feature of the south east depression of Ordos Plateau where the section stands, it is illustrated that the higher contents of SiO2 and the lower contents of Al2O3, TFe, Mn, TiO, K2O, MgO, CaO and Na2O in aeolian sands are related to cold dry windy predominated climate and to the amount immigration of quart, and the converse distribution situation in fluviolacustrine facies and palaeosol bear relation to this special relative obdurate depression where stable elements Al2O3, TFe, Mn, TiO and unstable elements K2O, MgO, CaO and Na2O can both gather together. The study shows that, in Salawusu River valley, the 27 cycles element change cycles since 150 ka B.P. bears relationship with the repeatedly alternation between winter monsoon and summer monsoon in the Mu Us Desert, influenced by the climate vicissitudes in the northern hemisphere during glacial periods and interglacial periods since 150 ka B.P.

关 键 词：萨拉乌苏河流域 气候旋回 沉积旋回 米浪沟湾剖面 内蒙古自治区 暖湿气候作用 

分 类 号：P595[天文地球—地球化学] P532[天文地球—地质学]