Journal of Geographical Sciences ›› 2005, Vol. 15 ›› Issue (1): 115-122.doi: 10.1360/gs050114

• Climate and Environmental Change • Previous Articles     Next Articles

Desert-steppe migration on the Loess Plateau at about 450 kaBP

ZHAO Jingbo1,2   

  1. 1. Geography Department of Shaanxi Normal University, Xi'an 710062, China;

    2. State Key Laboratory of Loess and Quaternary, Institute of Earth Environment, CAS, Xi'an 710054, China
  • Received:2004-09-10 Revised:2004-11-22 Online:2005-03-25 Published:2010-10-23
  • Supported by:

    State Key Discipline Project of Shaanxi Normal University, No.SNNUHG04007; Key Project of the Educational Ministry, No.01JAZJD770014

Abstract:

According to the field investigation, observation by an electronic microscope and x-ray identification and chemical analysis, desert-steppe migration in the Loess Plateau at about 450 kaBP was studied. The data show that gypsum illuvial horizon indicating the desert-steppe environment developed in the early stage of the formation of the fifth layer loess in Shaoling tableland in Chang'an and Bailu tableland in Xi'an of Shaanxi are situated in the southern Loess Plateau. This indicates that remarkable drying occurred, a large-scope migration of desert steppe took place toward south and the climate zone migrated 5 degrees in latitude to south which is the largest migration range indicated by geochemical indexes. The desert-steppe and more wild environment distributed widely on the Loess Plateau at that time. The development of gypsum also indicates that the climate changed at 450 kaBP from monsoon climate to nonmonsoon climate in the Loess Plateau, and the region was not affected by summer monsoon and was in the cold and dry environment of nonmonsoon climate. Annual mean precipitation was about 200 mm, 400 mm less at that time than at present.

Key words: null