DOI: 10.5194/cp-14-271-2018
Scopus记录号: 2-s2.0-85043366440
论文题名: Eolian dust dispersal patterns since the last glacial period in eastern Central Asia: Insights from a loess-paleosol sequence in the Ili Basin
作者: Li Y. ; Song Y. ; Fitzsimmons K.E. ; Chang H. ; Orozbaev R. ; Li X.
刊名: Climate of the Past
ISSN: 18149324
出版年: 2018
卷: 14, 期: 3 起始页码: 271
结束页码: 286
语种: 英语
Scopus关键词: dispersal
; eolian deposit
; grain size
; Heinrich event
; Holocene
; Last Glacial
; loess
; magnetic susceptibility
; midlatitude environment
; paleoclimate
; paleosol
; teleconnection
; Atlantic Ocean
; Atlantic Ocean (North)
; Central Asia
; Far East
; Ili Basin
英文摘要: The extensive loess deposits of the Eurasian mid-latitudes provide important terrestrial archives of Quaternary climatic change. As yet, however, loess records in Central Asia are poorly understood. Here we investigate the grain size and magnetic characteristics of loess from the Nilka (NLK) section in the Ili Basin of eastern Central Asia. Weak pedogenesis suggested by frequency-dependent magnetic susceptibility (I‡ fd%) and magnetic susceptibility (MS) peaks in primary loess suggest that MS is more strongly influenced by allogenetic magnetic minerals than pedogenesis, and may therefore be used to indicate wind strength. This is supported by the close correlation between variations in MS and proportions of the sand-sized fraction. To further explore the temporal variability in dust transport patterns, we identified three grain size end-members (EM1, mode size 47.5ĝ€μm; EM2, 33.6ĝ€μm; EM3, 18.9ĝ€μm) which represent distinct aerodynamic environments. EM1 and EM2 are inferred to represent grain size fractions transported from proximal sources in short-Term, near-surface suspension during dust outbreaks. EM3 appears to represent a continuous background dust fraction under non-dust storm conditions. Of the three end-members, EM1 is most likely the most sensitive recorder of wind strength. We compare our EM1 proportions with mean grain size from the Jingyuan section in the Chinese loess plateau, and assess these in the context of modern and Holocene climate data. Our research suggests that the Siberian High pressure system is the dominant influence on wind dynamics, resulting in loess deposition in the eastern Ili Basin. Six millennial-scale cooling (Heinrich) events can be identified in the NLK loess records. Our grain size data support the hypothesis that the Siberian High acts as teleconnection between the climatic systems of the North Atlantic and East Asia in the high northern latitudes, but not for the mid-latitude westerlies. © 2018 Author(s). Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/109588
Appears in Collections: 影响、适应和脆弱性 气候变化事实与影响
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作者单位: State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, 710061, China; Research Group for Terrestrial Palaeoclimates, Max Planck Institute for Chemistry, Mainz, 55128, Germany; College of Earth Science, University of Chinese Academy of Sciences, Beijing, 100049, China; Institute of Geology, National Academy of Sciences of Kyrgyz Republic, Bishkek, 720040, Kyrgyzstan; Research Center for Ecology and Environment of Central Asia, Chinese Academy of Sciences, Ürümqi, 830011, China
Recommended Citation:
Li Y.,Song Y.,Fitzsimmons K.E.,et al. Eolian dust dispersal patterns since the last glacial period in eastern Central Asia: Insights from a loess-paleosol sequence in the Ili Basin[J]. Climate of the Past,2018-01-01,14(3)