中国季风沙区晚更新世以来环境及其变化  

Environment and Its Changes in the Monsoon Sandy Region of China during the Late Pleistocene and Holocene

作　　者：李保生[1] 吴正[1] David Dian ZHANG 范安康[3] 阎满存[4] 孙武[1] 靳鹤龄[5] 董光荣[5] 祝一志[6] 高全洲[7] 张甲申[8] 

机构地区：[1]华南师范大学地理系,广州510631 [2]香港大学地理及地质学系 [3]华东师范大学教育部 [4]清华大学水利水电工程系,北京100084 [5]中国科学院寒区旱区环境与工程研究所,兰州730000 [6]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,西安710061 [7]中山大学地理系,广州510275 [8]北京大学城市与环境学系,100871

出　　处：《地质学报》2001年第1期127-137,共11页Acta Geologica Sinica

基　　金：国家自然科学基金(编号49971009);华东师范大学教育部城市与环境动态过程重点实验室基金

摘　　要：本文以对毛乌素沙漠萨拉乌苏河流域米浪沟湾地层剖面晚更新世—全新世砂丘与河湖相、古土壤互为叠覆的高分辨率的气候地层记录的认识出发,同时基于对中国北方现代冬春季节风沙、尘霾活动发生的区域性气候—地质过程的理解,将今释古,反演了该时期中国季风区沙漠沙地曾经历的27个沙漠扩缩的周期性变化,并认为该剖面风砂沉积是过去地质时代季风沙区乃至整个中国沙区类似由现代这种冬春季西伯利亚—蒙古反气旋风系即冬季风向南伸展导致的若干风沙风尘动态过程的结果,而河湖相和古土壤的发育则主要与季风沙区受惠于东亚夏季风的影响有关。Situated at the southeast magrin of the Mu Us Desert, the Milanggouwan stratigraphical section in the Salawusu River Valley records 27 depositional sequences of the aeolian dune layers alternating with the fluvio-la-custrine facies and palaeosols from the Late Pleistocene to Holocene. Grain-size analysis and measurements of the susceptibility of the section show that their changes in the section may be well correlated with the variations of the aeolian dune layers, fluvio-lacustrine facies and palaeosols. Usually, the particles of aeolian dunes are coarser and well sorted with lower susceptibility values (Sv), their MX (mean particle diameter),σ(standard deviation) and Sv being 2.33-3.48Φ, 0. 26-0. 90 and 2 - 10 (10-8 m3/kg SI) respectively; whereas the particles of the fluvio-lacustrine facies and palaeosols are finer, moderately to poorly sorted with higher susceptibili- ty values, their MX, σ and Sv falling within the range of 3. 04-5. 06Φ, 0. 61 - 1. 77 and 10-20 (10-8 m3/kg SI) respectively. Hereby it is considered with reference to the study results obtained by previous researchers that the above-mentioned alternately evolutionary sequences were, in fact, mainly induced by the climatic changes. The aeolian sand dune was deposited chiefly during the 'desert period' , formed under dry and cold climatic conditions; the fluvio-lacustrine facies and palaeosol are chiefly the product during the 'inter-desert period' , accumulated under warm humid climatic conditions. Thereby, the dune layers in the Milanggouwan section and its overlying fluvio-lacustrine facies or/and palaeosol may be regarded as a sedimentary cycle. A total of 27 cycles are recorded in the section. Each cycle represents a complete process from the cold dry to warm humid climate, and the region has experienced 27 climatic cycles of alternating cold dry and warm humid. Based on the understanding of the regional climate of the wind-drifting sands and the dust haze, induced by the southward stretch of the Sibrian-Mongolian anticyclones in the pr

关 键 词：中国季风区 晚更新世-全新世 湾地层剖面 沙漠期 气候波动 季风沙区 沉积环境 

分 类 号：P425.55[天文地球—大气科学及气象学]