毛乌素沙漠东南缘滴哨沟湾剖面DGS1层段粒度特征及其指示的全新世气候变化  

Climate Variations Recorded by the Grain-size from the DGS1 Segment in the Southeast of China′s Mu Us Desert During the Holocene

作　　者：舒培仙 李保生[1,2] 牛东风[1] 王丰年[3] 温小浩[1] 司月君[4] 陈琼[1] 

机构地区：[1]华南师范大学地理科学学院,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]惠州学院旅游系,广东惠州516007 [4]广西师范学院规划与地理科学学院,广西南宁530001

出　　处：《地理科学》2016年第3期448-457,共10页Scientia Geographica Sinica

基　　金：国家重点基础研究发展计划(973计划)(2013CB955903)项目;国家自然科学基金(41471159)项目资助~~

摘　　要：分析滴哨沟湾剖面全新统DGS1段的粒度数据,认为流动沙丘砂、泥炭、砂质古土壤、古固定-半固定沙丘砂到湖沼相和次生黄土的颗粒总体上变细,分选变差。结合腹足类动物化石和湖沼相地层中石英砂粒表面电镜扫描,认为DGS1粒度结果实际上是全新世以来多次冬夏季风的交互演替过程的气候-地质记录。据此,将DGS1粒度信号记录的全新世气候分为4个阶段——全新世早期好转期、全新世鼎盛期、大暖期向寒冷期转变波动期和降温不稳定的沙漠化频繁变化时期。The DGS 1 segment in the Dishaogouwan section from the Salawusu River valley is a typical stratum to study the climate variations in the Holocene. Based on the dating ages and analysis of the grain-size features within the DGS 1,we find that the particle gradually becomes finer but the sorting rate becomes poorer from mobile dune sands, peat, paleosols, semi-fixed sand dunes to the lacustrine facies and secondary loess; the grain-size parameter values of M2（Ф）, σ1（40, SK1 in the dune sands are lower than those in the lacustrine facies or secondary loess, and the Kc value shows opposite trends; the M, ranges from 2.26 to 3.36 （average 2.55） in the dune sands, 2.33 to 6.33 （average 4.28） in the lacustrine facies and 4.25 to 5.27 （average 4.58） in the secondary loess; the σ1（Ф） ranges from 0.51 to 2.51 （average 0.97） in the dune sands, 0.81 to 3.25 （average 2.13） in the lacustrine facies and 1.10 to 2.46 （average 1.46） in the secondary loess; the SK1 ranges from 0.0I to 0.45 （average 0.29） in the dune sands, 0.09 to 0.53 （average 0.32） in the lacustrine facies and 0.22 to 0.38 （average 0.36） in the secondary loess; the KG ranges from 0.92 to 1.70 （average 1.42） in the dune sands, 0.65 to 1.80 （average 1.13） in the lacustrine facies and 1.22 to 1.51 （average 1.44） in the secondary loess. They display distinct variations that correspond to the sedimentary changes. The surface microstructure of the quartz grains in the lacustrine facies under the electron microscope scanning shows typical aeolian characteristics with good round- ness, without precipitated silica, but with pits on the surface. Together with the freshwater gastropod fossils dis- covered in the stratigrapgical layers, we suggest that the grain-size cycles in the DGS 1 segment actually reflect the climate variations in the alternation of East Asian winter and summer monsoons in the Holocene, and the climate of the Holocene can be divided into four stages： the warming period of the Early Holoce

关 键 词：滴哨沟湾剖面 粒度 气候变化 全新世 毛乌素沙漠 

分 类 号：P532[天文地球—古生物学与地层学]