黄土记录的中亚干旱区东部全新世气候与环境演化  

Climatic and environmental evolution during the Holocene in the eastern Arid Central Asia recorded by loess-paleosol sequences

作　　者：范义姣 马箫忆 刘慧 王树源 杨军怀 陈梓炫 高福元 贾佳 夏敦胜[1] FAN Yijiao;MA Xiaoyi;LIU Hui;WANG Shuyuan;YANG Junhuai;CHEN Zixuan;GAO Fuyuan;JIA Jia;XIA Dunsheng(Key Laboratory of Western China’s Environmental Systems,Ministry of Education,College of Earth and Environmental Sciences,Lanzhou University,Lanzhou 730000,China;College of Geography and Environmental Engineering,Lanzhou City University,Lanzhou 730070,China;College of Geography and Environmental Sciences,Zhejiang Normal University,Jinhua 321004,Zhejiang,China)

机构地区：[1]兰州大学资源环境学院西部环境教育部重点实验室,甘肃兰州730000 [2]兰州城市学院地理与环境工程学院,甘肃兰州730070 [3]浙江师范大学地理与环境科学学院,浙江金华321004

出　　处：《冰川冻土》2021年第3期818-826,共9页Journal of Glaciology and Geocryology

基　　金：国家自然科学基金项目(41877444)资助。

摘　　要：选取位于中亚干旱区东部新疆天山地区的两个典型黄土沉积剖面,通过磁学参数(χARM/SIRM)、亮度(L*)、有机碳/氮同位素(δ13Corg和δ15N)等记录,对研究区内全新世以来的气候环境进行重建。结果表明:早全新世,χARM/SIRM、L*指示黄土成壤较弱、有机质含量低,δ13Corg记录表明区域降水较少,共同反映该时期地表植被覆盖低、相对干旱的气候环境;中晚全新世,χARM/SIRM、L*和δ13Corg记录的湿度逐渐增加,黄土δ15N偏正变化,指示地表生态系统生产力增强、植被覆盖增加,表明该区域气候适宜期发生在中晚全新世。中亚干旱区东部全新世以来的气候环境特征,与北半球高纬度冰盖、太阳辐射强度的变化密切相关。Two typical loess-paleosol sequences(KS16 and LJW10),located in the Tianshan region of Xinjiang in the eastern Arid Central Asia(ACA),were selected to reconstruct the climatic and environmental evolution during the Holocene.The susceptibility parameters(χARM/SIRM),lightness(L*),organic carbon/nitrogen iso⁃tope(δ13Corg andδ15N)of the KS16 section(43°25′56″N,83°56′35″E,1314 m a.s.l.)in the Ili Basin were analyzed comprehensively.In addition,we combined theδ15N of LJW10 section(43°58′29″N,85°20′10″E,1462 m a.s.l.),located in the northern Tianshan Mountains,and the proxies(χARM/SIRM,L*,δ13Corg,δ15N,)of KS16 section to reconstruct regional climatic and environmental evolution during the Holocene,which is help⁃ful to understanding the synergistic effects of climate change and ecological environment in the eastern Arid Cen⁃tral Asia.The results show that:During the early Holocene,theχARM/SIRM and L*both indicated the pedogene⁃sis was relatively weak and the organic matter content was low in the loess,with positiveδ13Corg showed regional precipitation was limited,which reflected the low vegetation coverage and relatively arid climate environment during this period.During the middle and late Holocene,the variations ofχARM/SIRM,L*andδ13Corg showed the moisture gradually increased,and theδ15N record presented more positive,which all indicated that the climatic optimum occurred at this period.The climatic and environmental characteristics of the eastern Arid Central Asia during the Holocene are closely related to the variations of the high latitude ice sheet and the intensity of insola⁃tion in northern hemisphere.

关 键 词：黄土 δ13Corg δ15N 全新世 新疆天山地区 中亚干旱区东部 

分 类 号：P532[天文地球—古生物学与地层学]