气候变化领域集成服务门户(CCPortal): Grain-size-dependent geochemical characteristics of Middle and Upper Pleistocene loess sequences from the Junggar Basin: Implications for the provenance of Chinese eolian deposits

CCPortal

DOI	10.1016/j.palaeo.2019.109458
	Grain-size-dependent geochemical characteristics of Middle and Upper Pleistocene loess sequences from the Junggar Basin: Implications for the provenance of Chinese eolian deposits
	Li, Xiaojing; Zan, Jinbo; Yang, Rongsheng; Fang, Xiaomin; Yang, Shengli
通讯作者	Zan, JB (通讯作者)
发表日期	2020
ISSN	0031-0182
EISSN	1872-616X
卷号	538
英文摘要	Thick loess-paleosol sequences are widely distributed in the arid inland basins of northwestern China. The geochemical composition of these sediments provides important constraints on the provenance of Chinese eolian deposits. However, grain-size-dependent geochemical characteristics of Early-Middle Pleistocene loess deposits from these arid inland basins have not been investigated. The paucity of such studies hinders a full understanding of provenance changes of loess deposits from the Chinese Loess Plateau (CLP). In the present study, we performed a detailed major, trace and rare earth element analysis of multiple grain-size fractions of Middle Pleistocene loess deposits from the Dongwan section (DW) in the Junggar Basin. We found that the major, trace and rare earth element concentrations of the DW loess are grain-size-dependent, with higher concentrations in the fine fraction. In addition, the < 5 mu m and 5-20 mu m fractions are more homogeneous in composition than the coarse fractions, indicating that they were extremely well mixed prior to deposition. Compared to contemporaneous loess deposits from the CLP and surface loess samples from Tajikistan and Ili Basin in Xinjiang, the loess deposits of the DW section have higher major element ratios of TiO2/Al2O3 and K2O/Al2O3, and REE ratios of La-N/Yb-N, Gd-N/Yb-N and La-N/Sm-N, indicating that the loess deposits in the Junggar Basin have distinctive local or regional geochemical characteristics. These results support the view that the Junggar Basin is not a potential source region of the loess in the CLP, at least since the Middle Pleistocene. Furthermore, temporal variations in the major element and REE ratios of the coarse fractions (20-75 mu m and > 75 mu m) from the DW section changed significantly at similar to 0.5 Ma, which may have arisen from intensified physical erosion or increased wind speeds in the northern Tianshan area.
关键词	TIBETAN PLATEAU MAGNETIC-PROPERTIES PALEOSOL SAMPLES ILI BASIN DESERT EVOLUTION SEDIMENTS UPLIFT FRACTIONS RECORDS
英文关键词	Major elements; Trace elements; Rare earth elements; Chinese Loess Plateau; Tianshan; Central Asia
语种	英语
WOS研究方向	Physical Geography ; Geology ; Paleontology
WOS类目	Geography, Physical ; Geosciences, Multidisciplinary ; Paleontology
WOS记录号	WOS:000508751800040
来源期刊	PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY
来源机构	中国科学院青藏高原研究所
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/259816
推荐引用方式 GB/T 7714	Li, Xiaojing,Zan, Jinbo,Yang, Rongsheng,et al. Grain-size-dependent geochemical characteristics of Middle and Upper Pleistocene loess sequences from the Junggar Basin: Implications for the provenance of Chinese eolian deposits[J]. 中国科学院青藏高原研究所,2020,538.
APA	Li, Xiaojing,Zan, Jinbo,Yang, Rongsheng,Fang, Xiaomin,&Yang, Shengli.(2020).Grain-size-dependent geochemical characteristics of Middle and Upper Pleistocene loess sequences from the Junggar Basin: Implications for the provenance of Chinese eolian deposits.PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY,538.
MLA	Li, Xiaojing,et al."Grain-size-dependent geochemical characteristics of Middle and Upper Pleistocene loess sequences from the Junggar Basin: Implications for the provenance of Chinese eolian deposits".PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY 538(2020).