Acta Geographica Sinica ›› 2017, Vol. 72 ›› Issue (5): 790-803.doi: 10.11821/dlxb201705003

• Climate Change and Surface Processes • Previous Articles     Next Articles

Age and provenance of Younger Dryas paleo-aeolian sandlayers in the Jin-Shaan Gorges of the Yellow River

Yuzhu ZHANG1,2(), Chunchang HUANG3, Yinglu CHEN3, Zhihai TAN4, Lirong YANG2, Yunxiang ZHANG2, Haijun QIU1, Bo LIU1, Fazhu ZHAO1   

  1. 1. College of Urban and Environmental Science, Northwest University, Xi'an 710127, China
    2. Department of Geology, Northwest University, Xi'an 710069, China
    3. College of Tourism and Environmental Sciences, Shaanxi Normal University, Xi'an 710119, China
    4. College of Environmental Sciences and Chemistry Engineering, Xi'an Polytechnic University, Xi'an 710048, China
  • Received:2016-12-15 Revised:2017-03-20 Online:2017-05-20 Published:2017-07-13
  • Supported by:
    National Natural Science Foundation of China, No.41471071, No.41401602;Project Funded by China Postdoctoral Science Fundation, No.2016M592829;Program for Key Science and Technology Innovation Team in Shaanxi Province, No.2014KCT-27

Abstract:

Fieldwork investigations were carried out in the Hukou-Longmen reach in the Jin-Shaan (Shanxi-Shaanxi) Gorges of the Yellow River. Paleo-aeolian sand layers were found interbedded in the Late Pleistocene and Holocene loess-soil profile—Beisangyu profile (BSY). Analytical results, including field investigation, magnetic susceptibility, grain-size distribution, surface textures of quartz sand, and geochemical elements, indicate that the paleo-aeolian sands are medium-sized sandy fine sands, which were formed in a dry and windy climate. And the extreme drought events recorded by paleo-aeolian sand layers were dated to 12.5-11.6 ka, with optically stimulated luminescence (OSL) dating method. The extreme drought event coincided with the Younger Dryas that was recorded by the lacustrine sediment profiles and the aeolian loess-soil profiles in the desert/loess transitional zone in the adjacent region. The paleo-aeolian sands were sourced mainly from ancient riverbed sands in the Jin-Shaan Gorges of the Yellow River. The Jin-Shaan Gorges is situated in a semi-arid zone with a temperate continental monsoonal climate. The region responds sensitively to global change. During the Younger Dryas period, the region is in an extremely dry and cold environment, with strong winter monsoon and weak summer monsoon. The water level of the Yellow River will decline obviously. Consequently, floodplains and channel bars in the river are exposed in a broad area, and a large quantity of sand material drifts to the banks of the river under the force of the wind, which becomes the main source of the paleo-aeolian sand layer in the platforms on the gentle slopes on both sides of the river valley. These results would be of great significance in further understanding the temporal regularities of the extreme drought event and the relations between extreme drought event and monsoonal climate change.

Key words: Yellow River, Jin-Shaan Gorges, Younger Dryas, paleo-aeolian sand layer, OSL dating