长江中游末次冰期风成堆积及其环境指示  

Aeolian deposits in the middle reaches of Changjiang river during the last glaciation and their environmental implication

作　　者：于玲玲[1] 贾玉连[1] 陈晓玲[1] 张静然[1] 孙倩[1] 郑林[1] 

机构地区：[1]江西师范大学鄱阳湖生态环境与资源研究重点实验室地理环境学院,南昌330022

出　　处：《华中师范大学学报（自然科学版）》2010年第1期158-162,共5页Journal of Central China Normal University：Natural Sciences

基　　金：江西师范大学鄱阳湖生态环境与资源研究重点实验室开放基金项目(PK2008011)

摘　　要：该文研究了长江中游发育末次冰期的风成堆积序列.彭泽红光、小学剖面为黄土状土→中细砂堆积,其间夹有4个淤泥层;沙场剖面,为厚层的中细砂,有4个砂质亚粘土和(或)湖相淤泥夹层.OSL与^(14)C_(org)测年揭示,前者对应末次冰期早、中期,后者为末次冰期中、后期的堆积.粒度与元素指标揭示,两剖面物质组成具有统一性,可能指示沙山堆积具有统一物质来源.推测这个源地是沙山上风向的长江河谷.小学剖面黄土状土是沙山发育过程中在下风向的衍生堆积.Dated with OSL of quartz and ^24Corg methods, we investigated three sections （Xiaoxue,Laofangzi and Sand field） to clarify the sedimentary stratigraghy of sand hills and to enhance the understanding of their environmental implication. Generally, the three sections developed in the last glaciation. Chemical element Rb. Sr. Ti. Mn. Ba. Zr contents in the grain size fraction of 〈20 um of sand were nearly the same as that of loesslike soil and lacstrine sediments. Grain size distribution of sediment of sand, loess-like soil and lacustrine layers of Xiaoxue and Laofangzi sections gradually changed, which suggested that these sediments had the similar context. In Sand field section, no distinct change of mean size of the first grain size totality was found at the boundary of sand layers and lacustrine and（or）sandy silt layers, which indicated that no change of winter monsoon occurred at this interval. These evidences implied that ： 1） although it was dif- ferent in the dynamics process of sand,silt and clay,sediments of sand layers,loess-like soil layers and lacstrine layers have the same source--the windward Changjiang floodplain; 2） loess-like soil is the ramification of sand mountains in the leeward; 3） sedimentary facies change from loess-like soil to sand layers during the last ice age implied the gradually southwardly shifting Changjiang River courses in the Hukou rift valley.

关 键 词：末次冰期 沙山 黄土状土 长江河谷 

分 类 号：P512[天文地球—地质学]