Abstract
Abstract. The Taklimakan Desert in the Tarim Basin is the largest desert in Central Asia, and is regarded as one of the main dust sources to the Northern Hemisphere. Late Cenozoic sedimentary sequences with intercalated in-situ aeolian dune sands in this area preserve direct evidence for the Asian desertification. Herein, we report a high-resolution multi-proxy climatic record from the precise magnetostratigraphic dated Hongbaishan section in the central Taklimakan Desert. Our results show that a fundamental climate change, characterised by significant cooling, enhanced aridity, and intensified atmospheric circulation, occurred at 2.8 Ma. Good correlations between paleo-environmental records in the dust sources and downwind areas suggest a broadly consistent climate evolution of northwestern China during the late Cenozoic, which is probably driven by the uplift of the Tibet Plateau and the Northern Hemisphere glaciation.
Highlights
These events led to the formation of large deserts in northwestern China and the accumulation of aeolian deposits in the downwind areas of the Chinese Loess Plateau (CLP) and the North Pacific (NP) (e.g. Liu, 1985; Rea et al, 1985)
The aeolian records from the NP showed that aeolian deposits existed across the entire Cenozoic, exhibiting stepwise increases in the mass accumulation rate, and suggesting progressively enhanced aridity in the source regions (e.g. Rea et al, 1985, 1998)
Since the wind intensity and/or the distance to the source regions are the main controlling factors affecting the concentration of the polydomain ferrimagnets (Begét and Hawkins, 1989; Chlachula, 2003; Zan et al, 2010), and because of the late Cenozoic sediments in the central Tarim Basin are proximal deposits (Zhu et al, 1980; Si et al, 2009), it is apparent that a higher magnetic susceptibility indicates a stronger intensity of the atmospheric circulation, and vice versa
Summary
The progressive retreat of the Tethys Sea and the stepwise uplift of the Tibetan Plateau during the Cenozoic resulted in the aridification and desertification in the Asian interior (e.g. Ramstein et al, 1997; Zhang et al, 2007; Manabe and Broccoli, 1990; Kutzbach et al, 1993; Ding et al, 1995; An et al, 2001; Lu et al, 2010; Molnar et al, 2010; Miao et al, 2012). Ramstein et al, 1997; Zhang et al, 2007; Manabe and Broccoli, 1990; Kutzbach et al, 1993; Ding et al, 1995; An et al, 2001; Lu et al, 2010; Molnar et al, 2010; Miao et al, 2012) These events led to the formation of large deserts in northwestern China and the accumulation of aeolian deposits in the downwind areas of the Chinese Loess Plateau (CLP) and the North Pacific (NP) To obtain more direct evidence for the Asian aridification and desertification, a better knowledge of the Cenozoic sedimentary records from the source regions is essential. In the central Taklimakan Desert, continuous late Cenozoic sequences with intercalated in-situ aeolian dune sand preserve direct evidence for the Asian desertification. Wang et al.: Late Cenozoic environment change from central Taklimakan Desert, China
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