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Journal of Desert Research ›› 2018, Vol. 38 ›› Issue (3): 516-523.DOI: 10.7522/j.issn.1000-694X.2018.00012

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Climate Change Revealed by Geochemical Major Elements during Holocene in the Southeastern Mu US Desert

Su Zhizhu1, Wu Yujing2, Kong Mengyuan2, Ma Yijuan2, Liang Aimin3,4, Liu Miaomiao5, Zhang Caixia3   

  1. 1. Historical Culture School, Shanxi University, Taiyuan 030006, China;
    2. College of Geography Science, Taiyuan Normal University, Jinzhong 030619, Shanxi, China;
    3. Key laboratory of Desert and Desertification, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China;
    4. University of Chinese Academy of Sciences, Beijing 100049, China;
    5. College of Environment and Resources, Shanxi University, Taiyuan 030006, China
  • Received:2017-08-09 Revised:2017-08-23 Online:2018-05-20 Published:2018-11-06

Abstract: The Mu US Desert located in the semi-arid area of northwest edge of China's monsoon region is typically sensitive to the global climate change, so this area is usually regarded as ideal area for research of climate change and desert evolution. The Jinjie profile (38°44'45″N, 110°09'56″E) of Shenmu County that located in Southeastern of Mu US Desert, has developed representative aeolian sand-paleosoil sedimentary structure. We analyzed sediment in Jinjie profile, based on data of OSL dating, geochemical major element oxides and the ratio of these elements, in combination with magnetic susceptibility and grain size. The result showed that:(1)The sediment of Jinjie profile was mainly composed of SiO2 and Al2O3, with the contents of 69.72%-81.40% and 11.04%-12.71%, the other major element oxides' contents are in order of Na > K > Fe > Ca > Mg. Chemical activity of different geochemical elements in the section showed obvious variability:K, Na and Si were more migrated and leached; while Ca, Mg, Fe, Al were obviously enriched. (2)The geochemical parameters can be used as the sensitive index to indicate the variability of Asian summer monsoon and winter monsoon. (3)The climate change in Southeastern of Mu US Desert since 7.9 ka BP can be classified into 6 stages:7.9-7.3 ka BP, the paleosoil layer is developed, the summer monsoon was powerful and the climate was warmest and wettest during this period, chemical weathering is strong and indicating accessing to the Holocene Optimum; 7.3-6.8 ka BP, the aeolian sand is developed, and the winter monsoon became stronger and the climate was cold and dry; 6.8-4.3 ka BP, the climate was warm and wet as a whole but still occurs two climatic fluctuations which become dry and cold from warm and wet, more than, there were six aeolian events were recorded at 6.6-6.3 ka BP, 6.1 ka BP, 5.9 ka BP, 5.7-5.5 ka BP, 5.3-5.0 ka BP, 4.7-4.4 ka BP; 4.3-2.5 ka BP, the winter monsoon became stronger again, the cold and dry climate was dominated; 2.5-1.8 ka BP, the climate was warm and humid, but the summer monsoon is weaker than the Holocene Optimum; Since 1.8 ka BP, the climate becomes colder and arider. The climate change in the study area reflects the strong and weak changes of East Asian monsoon and is coincident with the regional and global climate change.

Key words: geochemical major elements, climate change, Holocene, Mu US Desert

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