REE Geochemistry of a Weathering Profile in Guangxi, Southern China, and Genesis of Ion-Adsorption Type REE Deposit
Zhao Zhi
Wang Denghong
Pan Hua
Qu Wenjun
Abstract：X-ray diffraction (XRD),major and rare earth elements (REEs) geochemical characteristics of samples in a weathering profile from Guangxi were studied in order to reveal the geochemical behaviors of REEs during weathering.The profile can be divided into four layers from surface downwards:the humic layer (A1),the sub-clay layer(A2),the net-veined weathered layer (B1),and the completely weathered layer (B2).Clay minerals and chemical indexes of alteration (CIA) rapidly decrease from top to bottom.Samples from A1,A2 and Bl are enriched in Ce,Nd and heavy REE relative to their parent rocks.All samples are depleted in ion-exchangeable heavy REE and are relatively enriched in Y.Ion-exchangeable light and heavy REEs are enriched in the completely weathered layer.The ion-exchangeable REEs in the weathered granite are sourced mainly from labile REE-bearing minerals,such as allanite and titanate.The enrichment of heavy REE in samples from A1,A2 and B1 may have been caused by the residual zircon and xenotime,or the formation of supergene mineral,such as churchite-Y.The degree of weathering of granite leads to the change of the fractional degree of ion-exchangeable light and heavy REE.
Keywords：weathering profilerare earth elemention-exchangeable REEweathering degreegranitegeochemistry
Publication Date：2017-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：10( 1697-1706 )