Holocene Moisture Variation Recorded by Aeolian Sand-Palaeosol Sequences of the Gonghe Basin, Northeastern Qinghai-Tibetan Plateau, China  

作　　者：LIU Bing ZHAO Hui JIN Heling CHEN Fahu 

机构地区：[1]Key Laboratory of Desert and Desertification,Northwest Institute of Eco-Environment and Resources,Chinese Academy of Science,Lanzhou 730000,China [2]Key Laboratory of Western China's Environmental Systems,Ministry of Education,Lanzhou 73000,China [3]Key Laboratory of Alpine Ecology,Institute of Tibetan Plateau Research,Chinese Academy of Sciences,Beijing 100101,China

出　　处：《Acta Geologica Sinica(English Edition)》2020年第3期668-681,共14页地质学报（英文版）

基　　金：This study was supported by the Strategic Priority Research Program of Chinese Academy of Sciences, Pan-Third Pole Environment Study for a Green Silk Road (Grant No. XDA 2009000001);the National Natural Science Foundation of China (Grants No. 41977393 and 41671204)

摘　　要：The northeastern Qinghai-Tibetan Plateau(QTP) of China is located at the triple junction of the Asian winter and summer monsoons and the westerlies, where paleoclimatic evolution has an important scientific significance for recognizing the spatial-temporal pattern of Asian monsoons in the past and predicting environmental change in the future. Nevertheless, the framework of the Holocene moisture variation and related mechanisms remain controversial, owing to complex hydroclimatic conditions triggered by the landform of the large mountain-arid basin. Here, we employed geochemical proxies from typical aeolian sand-palaeosol sequences in the Gonghe Basin, northeastern QTP, together with Optically Stimulated Luminescence(OSL) dating, to reconstruct the pattern of effective moisture variation and associated mechanisms in this region. Our results indicate that the regional effective moisture was at its lowest until 9–8 ka, and approached a maximum during 8–4/3 ka of the middle Holocene. Afterwards, the climate became relatively dry in general, but with a transient humid interval around 2–1 ka. Our geochemical evidence indicates that the dry early Holocene probably can be attributed to a strong winter monsoon forced by remnant ice sheet, combined with the high evaporation caused by solar insolation. Also, shifts of humid-dry are closely linked to the Asian summer monsoonal strength and therefore the balance of evaporation-precipitation in the middle and late Holocene. Thus, the pattern of the Holocene effective moisture variation is characterized as the ‘monsoon model’ in a closed intermontane arid and semi-arid basin near the western Asian monsoonal limit.

关 键 词：effective moisture geochemical analysis aeolian deposits HOLOCENE Gonghe Basin 

分 类 号：P534.632[天文地球—第四纪地质学]