QQ客服 官方微博 反馈留言

	Geochemistry of red residua underlying dolomites in karst terrains of Yunnan-Guizhou Plateau II. The mobility of rare earth elements during weathering
	Ji H. B. ; Wang S. J. ; Ouyang Z. Y. ; Zhang S. ; Sun C. X. ; Liu X. M. ; Zhou D. Q.
	2004
关键词	REE fractionation abnormal enrichment the convex-up patterns red residua karst terrain cerium anomalies trace-elements mass-balance long-term sm-nd fractionation sediments carbonate profile soil
英文摘要	The aim of this study is to characterize the evolution of the rare earth elements (REE) in the Pingba red residua on karst terrain of Yunnan-Guizhou Plateau. The in-situ weathering and the two-stage development of the profile had been inferred from REE criterions. The REE were significantly fractionated, and Ce was less mobilized and separated from the other REEs at the highly enriched top of the profile. This is consistent with the increase of oxidation degree in the regolith. And it is also suggested that the wet/dry climate change during chemical weathering caused Ce alternative change between enrichment and invariance in the upper regolith. Chondrite-normalized REE distribution patterns for samples from dolomites and the lower regolith are characteristic of MREE enrichment and remarkable negative Ce-anomalies patterns (similar to the convex-up REE patterns). The following processes are interpreted for the patterns in this study: (1) the accumulation of MRRE-rich minerals in dolomite dissolution, (2) water-rock interaction in the weathering front, and (3) more leaching MREE from the upper part of the profile. The latter two explanations are considered as the dominant process for the formation of the REE patterns. Samples from the soil horizon exhibit typical REE distribution patterns of the upper crust, i.e., La-N/Yb-N = 10 and Eu/Eu* = 0.65. All data indicate that the leaching process is very important for pedogenesis in this region. The experiments demonstrating that abnormal enrichment of REE at the upper regolith-bedrock interface is caused by a combination of volume change, accumulation of REE-bearing minerals, leaching of REE from the upper regolith, and water-rock interaction during rock-soil alteration processes. Our results support the conclusion that the weathering profile represents a large, continental elemental storage reservoir, whereas REE enrichment occurs under favorable conditions in terms of stable tectonics, low erosion and rapid weathering over sufficiently long time. (C) 2003 Elsevier B.V. All rights reserved.
出处	Chemical Geology
卷	203
期	1-2
页	29-50
收录类别	SCI
语种	英语
ISSN号	0009-2541
内容类型	SCI/SSCI论文
源URL	[http://ir.igsnrr.ac.cn/handle/311030/23779]
专题	地理科学与资源研究所_历年回溯文献
推荐引用方式 GB/T 7714	Ji H. B.,Wang S. J.,Ouyang Z. Y.,et al. Geochemistry of red residua underlying dolomites in karst terrains of Yunnan-Guizhou Plateau II. The mobility of rare earth elements during weathering. 2004.

个性服务

查看访问统计

相关权益政策

暂无数据

收藏/分享

除非特别说明，本系统中所有内容都受版权保护，并保留所有权利。