Provenance of the upper Miocene-Pliocene Red Clay deposits of the Chinese loess plateau
Provenance of the upper Miocene-Pliocene Red Clay deposits of the Chinese loess plateau
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DOI：
10.1016/j.epsl.2014.09.026
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发表时间：
2014-12-01
影响因子：
5.3
通讯作者：
Fang, Xiaomin
中科院分区：
文献类型：
--
作者：
Nie, Junsheng;Peng, Wenbin;Fang, Xiaomin
了解中国晚新生代黄土及其下伏的红粘土沉积的物源，将有助于了解亚洲干旱化的历史和机制。尽管对中国黄土高原第四纪黄土来源的认识取得了很大进展，但下伏的中新世—上新世红粘土层序的物源仍是未知的。在此，我们基于中部的锆石U-Pb年龄给出了第一个红粘土层序的物源历史。U-Pb年龄群的目测和统计分析，以及与潜在源区结果的对比表明：(1)晚中新世最底层的红粘土（沉积年龄约8 Ma）可能来源于附近的六盘山和柴达木盆地；(2)中间红土(5)；(C) 2014 Elsevier B.V.版权所有
A clear understanding of the provenance of late Cenozoic Chinese loess and the underlying Red Clay deposits will shed light on the history and mechanisms of Asian aridification. Although much progress has been made in understanding the source of Quaternary loess on the Chinese Loess Plateau (CLP), the provenance of the underlying upper Miocene-Pliocene Red Clay sequence is largely unknown. Here we present the first provenance history of the Red Clay sequence based on zircon U-Pb ages from the central CLP. Visual and statistical analyses of the U-Pb age populations and comparison with results from potential source regions reveals that (I) the lowermost Red Clay of the late Miocene (depositional age of similar to 8 Ma) is likely sourced from the nearby Liupan Mountains and the Qaidam Basin; (2) the middle Red Clay (5.5-4 Ma) of the early-mid Pliocene is sourced mainly from the Taklamakan desert, transported via lower-level westerly winds; (3) the upper Red Clay of the late Pliocene (similar to 3 Ma) is sourced from mixed areas, although western source materials from middle-northern Tibetan plateau (including Qaidam Desert sediments and materials eroded from the Qilian Mountains) sediments appear to dominate; and (4) the Quaternary loess is also sourced from mixed source regions, albeit with dominant northern CLP proximal desert sediments transported via winter monsoon winds, which in turn may be transported from mountain source regions of the northeastern Tibet and Gobi Altai via major river systems. This long term shift in sources suggests a progressive eastward aridification during the Pliocene in Asia with the specific timing of provenance shifts synchronous with large-scale climatic transitions and Tibetan uplift, demonstrating that Asian desertification is controlled by both factors. (C) 2014 Elsevier B.V. All rights reserved.