Late Miocene–early Pleistocene paleoproductivity variations of the Lop Nor in the Tarim Basin and its implications on aridification in Asian Interior  

作　　者：Hong Chang Zhisheng An Weiguo Liu Feng Wu Xiaoke Qiang Yougui Song 

机构地区：[1]State Key Laboratory of Loess and Quaternary Geology,Institute of Earth Environment, Chinese Academy of Sciences

出　　处：《Chinese Science Bulletin》2014年第28期3650-3658,共9页

基　　金：supported by the National Basic Research Program of China (2010CB833400);the Tibetan Plateau Special Project from Chinese Academy of Sciences (XDB03020102);the National Natural Science Foundation of China (41290252, 40921120406)

摘　　要：Extensive lacustrine deposits in the eastern Tarim Basin provide records of climate change influenced by the westerly winds and the Asian monsoon. To characterize the evolution of climate change in this region, we analyze elemental concentrations of barium(Ba) from the Ls2 drill core of Lop Nor, a paleo-lakebed located in the eastern Tarim Basin. Biogenic Ba concentrations from this drill core display a large-amplitude oscillation that generally follows a pattern similar to that of Artemisia content and ostracod assemblages, suggesting that is may serve as an index for climate change experienced in the basin. Our results indicate that biogenic Ba is especially sensitive to precipitation. All climatic proxies served in this study vary significantly over late Miocene to early Pleistocene time period. Strong aridification of eastern Tarim in the late Miocene to the early Pliocene may be attributed to a latitudinal shift in the westerly winds, which would have resulted in more moisture transported to southern and eastern Tibet. The growth of the Himalaya and Tibetan Plateau may have acted as an orographic barrier that blocked moisture sourced in the south from the northern margins of the plateau. We link weaker aridification in the late Pliocene to an increased intensity of the Indian Monsoon.Extensive lacustrine deposits in the eastern Tarim Basin provide records of climate change influenced by the westerly winds and the Asian monsoon. To char- acterize the evolution of climate change in this region, we analyze elemental concentrations of barium （Ba） from the Ls2 drill core of Lop Nor, a paleo-lakebed located in the eastern Tarim Basin. Biogenic Ba concentrations from this drill core display a large-amplitude oscillation that gener- ally follows a pattern similar to that of Artemisia content and ostracod assemblages, suggesting that is may serve as an index for climate change experienced in the basin. Our results indicate that biogenic Ba is especially sensitive to precipitation. All climatic proxies served in this study vary significantly over late Miocene to early Pleistocene time period. Strong aridification of eastern Tarim in the late Miocene to the early Pliocene may be attributed to a lati- tudinal shift in the westerly winds, which would have resulted in more moisture transported to southern and eastern Tibet. The growth of the Himalaya and Tibetan Plateau may have acted as an orographic barrier that blocked moisture sourced in the south from the northern margins of the plateau. We link weaker aridification in the late Pliocene to an increased intensity of the Indian Monsoon.

关 键 词：晚中新世 早更新世 亚洲季风 塔里木河流域 干旱化 罗布泊 古生产力 塔里木盆地 

分 类 号：P534.63[天文地球—第四纪地质学] P532[天文地球—古生物学与地层学]