Abrupt environmental changes during the last 30 kyr in the southern margin of the Taklimakan Desert, a record from an oasis. (1st December 2018)

• Record Type: Journal Article
• Authors: Shu, Peixian; Li, Baosheng; Wang, Hong; Cheng, Peng; An, Zhisheng; Zhou, Weijian; Zhang, David Dian; Dodson, John; Niu, Dongfeng; Si, Yuejun; Wen, Xiaohao; Qiu, Yahui
• Is Part Of: Quaternary science reviews. Volume 201(2018)
• Page Start: 29
• Page End: 43
• Publication Date: 2018-12-01
• Subjects: Oasis -- Radiocarbon dating -- Abrupt environmental change -- Last glaciation -- Holocene -- Taklimakan desert; Geology, Stratigraphic -- Quaternary -- Periodicals; Stratigraphie -- Quaternaire -- Périodiques; 551.79
• DOI: 10.1016/j.quascirev.2018.09.036
• Languages: English
• ISSNs: 0277-3791

Abstract

Abstract: The Taklimakan Desert, the largest sand sea in China, is one of the most important sources of dust in the world. Millennial-scale abrupt climate changes during the last glacial and Holocene periods occurred in the region. However, these records remain poorly understood because dating eolian, lacustrine, and fluvial sediments and establishing reliable environmental proxies are challenging in this setting. Here, we use accelerator mass spectrometry (AMS), grain size, and Rb/Sr ratios of bulk sediments from an oasis sequence in the Taklimakan Desert. While some 14 C dates results are not in the stratigraphic order, most of them can be grouped in four age groups during the Last Glacial. We infer that reversals of radiocarbon age based on total organic carbon (TOC) was controlled by organic carbon (OC) input from the regional carbon pool. We selected 14 C dates from the four age groups, to develop an age-depth model for a basin-wide chronology. Peaks in a cumulative probability curve of radiocarbon dates, with high Rb/Sr ratios and fine mean grain sizes, reveal four wet periods during the Last Glaciation, and one wetter/warmer period during the Holocene. The regional moisture variability appears to be influenced by the Asian summer monsoon and mid-latitude Westerlies. The Holocene wetter/warmer period facilitated human occupation of the oasis. Highlights: A substantial reversal of radiocarbon dates on total organic carbon from an oasis sequence was found to be controlled by regional organic carbon input. We developed a reasonable age-depth model for the basin-wide chronology. The oasis record provides evidence for abrupt environmental changes associated with five wet periods during the last 30 kyr in Taklimakan Desert. The wetter and warmer conditions during the Holocene facilitated human occupation in the oasis of the Taklimakan Desert.