title: Late Miocene episodic lakes in the arid Tarim Basin, western China.
abstract: The Tibetan Plateau uplift and Cenozoic global cooling are thought to induce enhanced aridification in the Asian interior. Although the onset of Asian desertification is proposed to have started in the earliest Miocene, prevailing desert environment in the Tarim Basin, currently providing much of the Asian eolian dust sources, is only a geologically recent phenomenon. Here we report episodic occurrences of lacustrine environments during the Late Miocene and investigate how the episodic lakes vanished in the basin. Our oxygen isotopic (δ(18)O) record demonstrates that before the prevailing desert environment, episodic changes frequently alternating between lacustrine and fluvial-eolian environments can be linked to orbital variations. Wetter lacustrine phases generally corresponded to periods of high eccentricity and possibly high obliquity, and vice versa, suggesting a temperature control on the regional moisture level on orbital timescales. Boron isotopic (δ(11)B) and δ(18)O records, together with other geochemical indicators, consistently show that the episodic lakes finally dried up at ∼4.9 million years ago (Ma), permanently and irreversibly. Although the episodic occurrences of lakes appear to be linked to orbitally induced global climatic changes, the plateau (Tibetan, Pamir, and Tianshan) uplift was primarily responsible for the final vanishing of the episodic lakes in the Tarim Basin, occurring at a relatively warm, stable climate period.
authors.affiliation: State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710075, China; School of Human Settlement and Civil Engineering, Xi'an Jiaotong University, Xi'an 710049, China; zhliu@hku.hk liuwg@loess.llqg.ac.cn.
authors.forename: Weiguo
authors.initials: W
authors.lastname: Liu
authors.affiliation: Department of Earth Sciences, The University of Hong Kong, Hong Kong; and zhliu@hku.hk liuwg@loess.llqg.ac.cn.
authors.forename: Zhonghui
authors.initials: Z
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710075, China; School of Human Settlement and Civil Engineering, Xi'an Jiaotong University, Xi'an 710049, China;
authors.forename: Zhisheng
authors.initials: Z
authors.lastname: An
authors.affiliation: Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China.
authors.forename: Jimin
authors.initials: J
authors.lastname: Sun
authors.affiliation: State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710075, China;
authors.forename: Hong
authors.initials: H
authors.lastname: Chang
authors.affiliation: State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710075, China;
authors.forename: Ning
authors.initials: N
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710075, China;
authors.forename: Jibao
authors.initials: J
authors.lastname: Dong
authors.affiliation: State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710075, China;
authors.forename: Huanye
authors.initials: H
authors.lastname: Wang
keywords: Late Miocene; Milankovitch; Tarim Basin; aridification; tectonic uplift