风成沉积物色度记录的毛乌素沙漠全新世以来气候变化  

Climate Change in the Mu Us Desert since Holocene Based on Soil Chromaticity

作　　者：刘荔昀 鲁瑞洁 刘小槺 Liu Liyun;Lu Ruijie;Liu Xiaokang(State Key Laboratory of Earth Surface Processes and Resource Ecology/Engineering Center of Desertification and Blown-Sand Control of Ministry of Education/Key Laboratory of Environmental Change and Natural Disaster of Ministry of Education,Faculty of Geographical Science,Beijing Normal University,Beijing 100875,China;School of Geography and Tourism,Shaanxi Normal University,Xi'an 710119,China)

机构地区：[1]北京师范大学地理科学学部地表过程与资源生态国家重点实验室/防沙治沙教育部工程研究中心/环境演变与自然灾害教育部重点实验室,北京100875 [2]陕西师范大学地理科学与旅游学院,陕西西安710119

出　　处：《中国沙漠》2019年第6期83-89,共7页Journal of Desert Research

基　　金：国家自然科学基金重点项目(41330748);国家重点研发计划重大自然灾害监测预警与防范重点专项(2017YFC1502401)

摘　　要：以毛乌素沙漠4个全新世风成砂-古土壤剖面为研究对象,对沉积物色度变化进行分析。结果表明:亮度主要受有机质影响,从而间接反映降水;红度与磁化率负相关,与平均粒径呈正向趋势,因此红度主要取决于风力对红色物质的输入,即反映风力大小。古土壤发育时期,亮度偏低,红度、黄度偏低;风成砂沉积时期,亮度较高,红度、黄度较高。据此将毛乌素沙漠全新世以来的气候演变划分为4个阶段:约10.0 ka BP以前,以风沙环境为主,干燥寒冷、风力较大;10.0-7.5 ka BP,总体环境较之前好转,风沙活动减弱,局部区域发育古土壤;7.5-3.0 ka BP,气候以暖湿为主,古土壤普遍发育,风沙活动较弱;约3.0 ka BP至今,气候趋于干冷,风沙活动强烈,但期间也存在暖湿波动。Using colour index of the four aeolian deposits sections(GLT section, WPL section, ZBT section, CC section), the chronology of these sediments sequences was built by 14C and OSL dating. The climate change of the Mu Us Desert was reconstructed since Holocene. The brightness(L*) is influenced by organic matters which may indirectly reflects the precipitation. Redness(a*) is negatively correlated with the magnetization rate and positively correlated with the average particle size(Mz). Therefore, redness mainly depends on the input of wind force to red matter, which reflects the wind force. At the intervals of paleosol development, the values of the redness, yellowness and lightness are low. And during the cold-dry period, the aeolian activity is strong. The values of the redness, yellowness, lightness are high. In general, the development of Holocene climate has been divided into four stages: The area was dominated by dry, cold and windy aeolian environment before 10 000 BP. During 10 000-7 500 BP, the environment of the desert was better than before, the aeolian activities were weakened, and the palaeosol developed. At the 7 500-3 000 BP intervals, the climate was mainly warm and humid, the palaeosol widely developed, with episodic aeolian activities. Since 3 000 BP to present, the climate tends to be dry and cold. Although the aeolian activities were strong, there were also warm and wet fluctuations during the period.

关 键 词：全新世 色度 毛乌素沙漠 气候变化 

分 类 号：P531[天文地球—古生物学与地层学]