| Pedogenic processes in loess-paleosol sediments: Clues from Li isotopes of leachate in Luochuan loess | |
He, Mao-Yong1,2; Dong, Ji-Bao1,2; Jin, Zhangdong1,2,3; Liu, Chun-Yao4; Xiao, Jun1,2; Zhang, Fei1,2; Sun, He5; Zhao, Zhi-Qi6; Gou, Long-Fei1; Liu, Wei-Guo1,2; Luo, Chong-Guang7; Song, You-Gui1,2 ; Ma, Long8,9; Deng, Li1,2,10,11
| |
| Corresponding Author | He, Mao-Yong(hemy@ieecas.cn) ; Jin, Zhangdong(zhdjin@ieecas.cn) |
| 2021-04-15 | |
| Source Publication | GEOCHIMICA ET COSMOCHIMICA ACTA
 |
| ISSN | 0016-7037 |
| Volume | 299Pages:151-162 |
| Abstract | Tracing pedogenic processes is fundamental for reconstructing climatic and environmental changes using loess deposits. Lithium isotopes can serve as a sensitive tracer to unravel these processes, owing to its active behaviors without effect by redox and biological reactions. This study investigated the Li contents and delta Li-7 values of leachate and residue ([Li](leachate), [Li](residue), delta Li-7(leachate) and delta Li-7(residue)) of the upper 12.5m Luochuan loess-paleosol sediment (since the last interglacial) on the Chinese Loess Plateau, in order to better understand pedogenic processes in loess. The [Li](leachate), varying from 0.39 to 1.97 mu g/g, is mainly derived from the adsorption phase, with a significant variation in delta Li-7(leachate), from -6.55 parts per thousand to +12.88 parts per thousand. Both [Li](leachate) and delta Li-7(leachate) variations reflect weathering and adsorption processes during different periods. The [Li](residue) vary from 34.4 to 46.3 mu g/g (averaging 38.4 mu g/g) and their delta Li-7(residue) vary from -3.66 parts per thousand to +2.44 parts per thousand (averaging -0.22 +/- 1.68 parts per thousand), both in agreement with the upper continental crust values. At initial stage after loess deposited (stage I), high [Li](leachate) but low delta Li-7(leachate) are results of preferential adsorption of Li-6 by clays and migration of 7Li with soil solution during weathering and eluviation processes. When overlying loess was deposited and experienced pedogenesis as the stage I, Li-7 migrated downward and was adsorbed by clays (stage II), resulting in high [Li](leachate) and delta Li-7(leachate) in underlying loess. When loess has superimposed pedogenic and adsorption processes as the stages I and II, loess became as paleosol with highest delta Li-7(leachate) in underlying carbonate accumulation layer. A persistent increase in delta Li-7(leachate) indicates dominant control of post-depositional adsorptions on Li fractionation along solution migrations during weathering and eluviation of overlying deposits, and vice versa. These results highlight that variations in [Li](leachate) and delta Li-7(leachate) can be used to trace soil water migration processes and the magnitude of pedogenic processes in loess-paleosol sediment at different periods. (C) 2021 Elsevier Ltd. All rights reserved. |
| Keyword | Lithium isotopic composition Loess-paleosol deposits Pedogenic processes Weathering Eluviation Migration |
| DOI | 10.1016/j.gca.2021.02.021 |
| Indexed By | SCI ; SCI |
| Language | 英语 |
| Funding Project | CAS Interdisciplinary Innovation Team ; NSFC[41930863] |
| WOS Research Area | Geochemistry & Geophysics |
| Funding Organization | CAS Interdisciplinary Innovation Team ; NSFC |
| WOS Subject | Geochemistry & Geophysics |
| WOS ID | WOS:000632521900009 |
| Publisher | PERGAMON-ELSEVIER SCIENCE LTD |
| Citation statistics | |
| Document Type | 期刊论文 |
| Identifier | http://ir.ieecas.cn/handle/361006/16193 |
| Collection | 加速器质谱中心 第四纪科学与全球变化卓越创新中心 |
| Corresponding Author | He, Mao-Yong; Jin, Zhangdong |
| Affiliation | 1.Chinese Acad Sci, Inst Earth Environm, State Key Lab Loess & Quaternary Geol, Xian 710061, Peoples R China 2.CAS Ctr Excellence Quaternary Sci & Global Change, Xian 710061, Peoples R China 3.Xi An Jiao Tong Univ, Inst Global Environm Change, Xian 710049, Peoples R China 4.UCL, London Geochem & Isotope Ctr LOGIC, Gower Pl, London WC1E 6BT, England 5.Hefei Univ Technol, Sch Resources & Environm Engn, Hefei 230009, Peoples R China 6.Changan Univ, Sch Earth Sci & Resources, Xian 710054, Peoples R China 7.Chinese Acad Sci, Inst Geochem, State Key Lab Ore Deposit Geochem, Guiyang 550002, Peoples R China 8.Northwest Univ, Dept Geol, State Key Lab Continental Dynam, Xian 710069, Peoples R China 9.Northwest Univ, Dept Geol, Shaanxi Key Lab Early Life & Environm, Xian 710069, Peoples R China 10.Shaanxi Key Lab Accelerator Mass Spectrometry Tec, Xian 710061, Peoples R China 11.Natl Observat & Res Stn, Crit Zone & Terr Surface Flux, Chinese Loess Plateau, Xian 710061, Peoples R China |
| Recommended Citation GB/T 7714 | He, Mao-Yong,Dong, Ji-Bao,Jin, Zhangdong,et al. Pedogenic processes in loess-paleosol sediments: Clues from Li isotopes of leachate in Luochuan loess[J]. GEOCHIMICA ET COSMOCHIMICA ACTA,2021,299:151-162. |
| APA | He, Mao-Yong.,Dong, Ji-Bao.,Jin, Zhangdong.,Liu, Chun-Yao.,Xiao, Jun.,...&Deng, Li.(2021).Pedogenic processes in loess-paleosol sediments: Clues from Li isotopes of leachate in Luochuan loess.GEOCHIMICA ET COSMOCHIMICA ACTA,299,151-162. |
| MLA | He, Mao-Yong,et al."Pedogenic processes in loess-paleosol sediments: Clues from Li isotopes of leachate in Luochuan loess".GEOCHIMICA ET COSMOCHIMICA ACTA 299(2021):151-162. |
| Files in This Item: | There are no files associated with this item. | |||||
Items in the repository are protected by copyright, with all rights reserved, unless otherwise indicated.
Edit Comment