Geochemical Characteristics of Major Elements and Its Paleoenvironmental Significance of Holocene Loess Profile in Southern Shanxi, China
详细信息
- 责任者：Li Tuoyu (College of Urban and Environmental Sciences ; Peking University ; Beijing 100871 ; China) ; Mo Duowen
- 刊名：Geographical Research
- 出版年：2013
- 卷期：32(8)
- 关键词：全新世 ; 黄土 ; 元素地球化学 ; 山西
- 页码：p.1411-1420
- 图表：5 illus., 3 tables, 43 refs.
- 分类号：1400
- issnNo：ISSN1000-0585
- isbnNo：CN11-1848/P
摘要
Based on the analysis of major elements,magnetic susceptibility,grain size and optically stimulated luminescence(OSL) dating of samples from the Zhongliangtiechang(ZLTC) profile in southern Shanxi Province,China,using comprehensive approaches such as Chemical Index of Alteration(CIA),loss and accumulation of major elements relative to UCC,A-CN-K diagram,the geochemical characteristics and its paleoenvironmental significance are discussed.The results show that the chemical compounds consist mainly of SiO2,Al2O3,CaO and TFe2O3.The curves of Al2O3,TFe2O3 and K2O have the same trend,and the three elements come out top in paleosol layer when the climate is warm-wet.Ca enriches while Na and K decrease in ZLTC profile relative to UCC,which possibly represents the characteristics of loess in the source region.The climate is the main factor which influences the feldspar weathering process,and the feldspar weathering is mostly showing up to plagioclase feldspar weathering.The profile is in low weathering intensity as a whole,which lies between profiles in Fufeng of Shanxi and Pengyang of Ningxia;the sequence is in accordance with recent climate conditions in the three regions.The paleosol layer is in medium weathering intensity,in which Ca and Na leached greatly;while the loess layer is in low weathering intensity.Geochemical characteristics of major elements indicate that the climate "cool-dry(9.6-10.5 ka BP)-> warm-wet(4.9-9.5 ka BP)-> warm-dry(2.5-4.9 ka BP)-> cool-dry(since 2.5 ka BP)".During 1.2-2.5 ka BP,the content of particles with grain size above 100 μm is the highest,the deposition rate is high,and Ca leaches relatively,which represents the sheet erosion is strong at that time.