气候变化领域集成服务门户(CCPortal): Variations of the East Asian monsoon over the past 800 kyr constrained by the boron isotope composition of paleo-rainwater inferred from loess-paleosol deposits in NE China

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DOI	10.1016/j.epsl.2021.116826
	Variations of the East Asian monsoon over the past 800 kyr constrained by the boron isotope composition of paleo-rainwater inferred from loess-paleosol deposits in NE China
	Lei F.; Wei H.-Z.; Yi S.-W.; Zeng L.; Lu H.-Y.
发表日期	2021
ISSN	0012821X
卷号	561
英文摘要	Based on a study of the boron (B) isotope geochemistry of the loess-paleosol sequence of the Niuyangzigou section (NYZG) in Northeast (NE) China, the boron isotopic composition of paleo-rainwater (δ11Bpr) is used for the first time as a potential proxy for tracing changes in the East Asian summer monsoon (EASM) since the mid-Pleistocene. The acid-soluble phase of loess in NE China, which is characteristically a sandy loess, has lower boron concentrations (0.26 to 0.89 μg/g) and more positive δ11B values, from −12.1‰ to +9.4‰, compared to the loess of the Chinese Loess Plateau (CLP). According to the mass balance of boron accumulation from three distinct sources, a mathematical inversion calculation is used to quantify the proportion of boron from each source and to capture the original δ11Bpr signature. The resulting δ11Bpr values range from +6.8 ± 0.95‰ in loess layers to +17.3 ± 3.32‰ in paleosol layers, and the boron accumulated in loess-paleosol layers is shown to be mainly from atmospheric precipitation and silicate weathering. Synchronous variations of reconstructed δ11Bpr and other loess-based proxies, both in NE China and in the CLP, are observed over a large spatial range and on several temporal scales. The linkage of δ11Bpr to the intensity of the EASM is attributed to the kinetic boron isotope fractionation associated with vapor-precipitate phase separation along the transport path of moisture-bearing air masses. A Rayleigh fractionation model is proposed to interpret δ11Bpr in terms of the proportion of water vapor loss after multi-step fractionation processes, which is independent of temperature. The monsoon record based on δ11Bpr shows a significant shift at ∼430 ka, implying an abrupt weakening of the EASM after the Mid-Brunhes Event (MBE), which provides evidence for regional disparities in monsoon evolution in response to the MBE. The ice volume in Northern Hemisphere is a possible factor controlling changes in the EASM in NE China over the past 800 kyr. © 2021 Elsevier B.V.
关键词	B isotopic composition East Asian summer monsoon loess-paleosol sequence paleo-rainwater Rayleigh isotope fractionation
英文关键词	Atmospheric thermodynamics; Boron; Exploratory geochemistry; Fractionation; Isotopes; Phase separation; Sediments; Silicates; Weathering; Atmospheric precipitation; Boron isotope fractionation; Chinese Loess Plateau; East Asian summer monsoon; Fractionation process; Inversion calculations; Rayleigh fractionation; Synchronous variation; Boron deposits; boron isotope; isotopic composition; isotopic fractionation; loess; monsoon; paleoclimate; paleosol; Pleistocene; rainwater; temporal variation; China; Loess Plateau
语种	英语
来源期刊	Earth and Planetary Science Letters
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/203180
作者单位	School of Geography and Ocean Science, Nanjing University, Nanjing, 210023, China; State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, Nanjing, 210023, China; School of Resources and Environmental Engineering, Ludong University, Yantai, 264025, China
推荐引用方式 GB/T 7714	Lei F.,Wei H.-Z.,Yi S.-W.,et al. Variations of the East Asian monsoon over the past 800 kyr constrained by the boron isotope composition of paleo-rainwater inferred from loess-paleosol deposits in NE China[J],2021,561.
APA	Lei F.,Wei H.-Z.,Yi S.-W.,Zeng L.,&Lu H.-Y..(2021).Variations of the East Asian monsoon over the past 800 kyr constrained by the boron isotope composition of paleo-rainwater inferred from loess-paleosol deposits in NE China.Earth and Planetary Science Letters,561.
MLA	Lei F.,et al."Variations of the East Asian monsoon over the past 800 kyr constrained by the boron isotope composition of paleo-rainwater inferred from loess-paleosol deposits in NE China".Earth and Planetary Science Letters 561(2021).