作　　者： ; ; ; ; ; ; ; ;

机构地区： 中山大学地理科学与规划学院地理科学系

出　　处： 《地理学报》 1998年第B12期44-51,共8页

摘　　要： 根据约128ka BP以来查格勒布鲁剖面沉积地球化学特征的变化规律,研究了末次间冰期以来本区对全球气候波动的响应。随着全球气候的波动,间冰期和间冰阶时,东亚夏季风的降水尾间到达甚至越过本区向西扩展,给本区带来一定的降水,使之具有生草成壤的类似于干草原的环境,该时期剖面中发育湖相、黄土和古土壤沉积,SiO_2/Al_2O_3比值下降,平均值分别为9.33、7.58和7.51;冰期和冰阶时,东亚夏季风向东南方向退缩,本区受干冷的冬季风控制,降水稀少,植被稀疏,风沙活动强烈,剖面中发育风成砂沉积,SiO_2/Al_2O_3比值上升。据气候干寒程度的差异,风成砂的性状可划分为3类,即风成砂(Ⅰ)、风成砂(Ⅱ)和风成砂(Ⅲ),它们的SiO_2/Al_2O_3,比值分别为15.42、15.40和10.32,代表着从流动沙丘砂向固定-半固定沙丘砂的过渡。 The Chagelebulu section lies in the southern fringe of Badain Jaran Desert, Inner Mongolia , China. In this paper, the compositions of bulk chemical element of fifty-seven sediments in the section were analyzed with the method of fluorescence X-ray, which reflect the climatic evolu-tion in this area in response to global change since the last interglacial period. The periodic swing of the East Asia summer monsoon rain fringe in this area is the main reason to explain the complex facies changes of the section since 128 ka BP, i.e. , lacustrine deposit, the layer of peb-ble with sand, loess, paleosoil and eolian sand interlaced with each other frequently from the bottom to the top of the section. The weathering degrees of those deposits are different from each other. We arranged those deposits according to their silica-alumina ratios that were thought to be the reflection of their weathering from low value to high value degrees as follow-ing:Eolian sand ( I ) -Aeolian sand ( I )eolian sand (?- the layers of pebble with sand Q3Z lacustrine deposits昋31 lacustrine deposits loess paleosoil.With the fluctuation of the Quaternary glacial climate, the East Asia summer monsoon rain fringe could reach and even exceed this area during interglacial periods or stages and post-glacial period when the desert environment was transformed into a kind of steppe one, and the dunes were fixed completely or partly. Lacustrine deposit, loess and paleosol were formed in those pe-riods in the section which silica-alumina ratio is 9-33, 7.58 and 7.51, respectively. Former fixed dunes activated again during glacial period or stages when the dry and cold winter monsoon dominated the area. and eolian sand spread extensively in this area. Eolian sand was formed in those periods in the section which could be divided into 3 kinds according to their activation de-grees, i. e. eolian sand ( I ), eolian sand ( I ) and eolian sand ( B ) mentioned in this paper, which silica-alumina ratio is 15. 42, 15. 40 and 10. 32, respectively, reflecting the

关 键 词： 沉积地球化学 风成砂 剖面 东亚夏季风 降水 全球气候 冬季风 性状

领　　域： [天文地球] [天文地球] [天文地球] [天文地球]