古尔班通古特沙漠南缘风沙沉积记录的中晚全新世气候变化  

Mid-Late Holocene climate change recorded by eolian sand deposition in the southern margin of Gurbantunggut Desert

作　　者：邹晓君 马运强 李志忠[1,2,3] 靳建辉[1,2,3] 刘瑞 谭典佳 陶通炼 Zou Xiaojun;Ma Yunqiang;Li Zhizhong;Jin Jianhui;Liu Rui;Tan Dianjia;Tao Tonglian(College of Geographical Science,Fujian Normal University,Fuzhou 350117,China;Key Laboratory for Humid Subtropical Eco-Geographical Processes of the Ministry of Education,Fujian Normal University,Fuzhou 350117,China;Institute of Geography,Fujian Normal University,Fuzhou 350117,China)

机构地区：[1]福建师范大学地理科学学院,福建福州350117 [2]福建师范大学湿润亚热带生态地理过程国家重点实验室培育基地,福建福州350117 [3]福建师范大学地理研究所,福建福州350117

出　　处：《中国沙漠》2023年第6期98-110,共13页Journal of Desert Research

基　　金：国家自然科学基金项目(42071011);福建师范大学研究生科研创新基金项目。

摘　　要：古尔班通古特沙漠是中国受西风环流影响最明显、面积最大的固定半固定沙漠,但全新世以来沙漠风沙活动的时空变化特征及其成因尚存争议。选取沙漠南部边缘两处沙丘(沙垄)剖面加密采样,进行光释光测年和砂样粒度组分测试,基于光释光年龄概率密度分析和风积物粒度端元分析,综合提取风积序列光释光年代和粒度参数记录的风沙气候变化信息。结果表明:(1)从风积物粒度端元组分提取的敏感组分是区域风沙活动信息的重要气候代用指标,近源搬运的粗组分主要反映沙丘尺度的风沙活动信号,远源输送的细组分反映沙漠尺度的风沙活动信号;(2)上风边缘高输沙势地区的风积序列较多记录了沙丘尺度风沙活动信号,而下风低输沙势地区的风积序列较多记录了沙漠尺度的风沙活动信号;(3)全新世中晚期以来,研究区风沙活动强度变化可划分为5.0~3.5、3.5~1.8、1.8 ka BP至今3个阶段,风沙活动的区域性和阶段性特征是北半球西风环流变化、气候干湿变化以及局地尺度风动力、砂物质来源、植被覆盖等因素综合作用的结果。The Gurbantunggut Desert is the largest fixed and semi-fixed desert in China which is affected by the westerly circulation most obviously.However,the spatio-temporal characteristics and causes of desert aeolian sand activities since the Holocene are still controversial.Therefore,we selected two sand dunes(sand ridges)profiles at the southern edge of the desert,sampled and measured optically stimulated luminescence(OSL)age and grain size composition of sand samples.Based on the probability density analysis of OSL ages and the endmember analysis of aeolian grain size,the information of aeolian climate changes recorded by OSL ages and grain size parameters was extracted comprehensively.The results show that:(1)The sensitive components extracted from the grain size end-member components of aeolian deposits are important climatic proxies for regional sand activity information.The coarse components transported from near sources reflect the aeolian activities signal at the dune scale,and the fine components transported from far sources reflect the aeolian activities signal at the desert scale.(2)The aeolian sand activity signals at dune scale were mostly recorded by the sand deposition in the upwind edge area with high sand drift potential,while the aeolian sand activity signals at desert scale were mostly recorded by the sand deposition in the downwind area with low sand drift potential.(3)Since the middle and late Holocene,the intensity of aeolian sand activity in the study area can be divided into three stages:5.0-3.5 ka,3.5-1.8 ka BP and 1.8 ka BP.The regional and periodic characteristics of aeolian sand activity were the results of the combined effects of westerly circulation changes in the Northern Hemisphere,arid and humid changes of climate,local-scale wind power,sand source,vegetation coverage and other factors.

关 键 词：风沙沉积序列 OSL年龄概率密度 粒度端元分析 中晚全新世 古尔班通古特沙漠 

分 类 号：P631[天文地球—地质矿产勘探]