Rare earch element contents and patterns in major skarn minerals from Shizhuyuan W, Sn, Bi and Mo deposit, South China.

Abstract

Rare earth element (REE) contents and distribution patterns in the major rock-forming minerals (vesuvianite, wollastonite, garnet, pyroxene, hornblende, epidote and fluorite) from the Shizhuyuan W, Sn, Mo and Bi-containing skarn deposit of Hunan Province of South China have been determined. Three types of REE distribution patterns were found: 1) vesuvianite and wollastonite, formed at the expense of carbonates and shales of the Upper Devonian Shetianqiao Formation during thermal metamorphism stage, show linear light REE enrichment and small Eu anomalies; 2) garnet, the most abundant mineral in the skarn deposited at metasomatic stage, exhibits high REE enrichment and considerable negative Eu anomalies; 3) epidote and fluorite, precipitated during retrograde alteration stage, display very strong negative Eu anomalies. Comparison of relative REE abundances in these minerals with those in the carbonates and shales as well as in the Qianlishan Yanshanian granite suggests that REE compositions of the vesuvianite and wollastonite appear to have been inherited from precursor carbonates and shales, whereas REE contents and patterns in the metasomatic and the retrograde alteration products, such as garnet and epidote, seem to have been determined by the interactions between the reacting minerals and hydrothermal solutions originated from Qianlishan granite.