| Abstract:In terms of REE geochemical characteristics the tin/tungsten-bearing granites of transformation series or S-type in South China call be subdivided into four distribution patterns；(1) REE-normal type, character ized by ∑REE = 250—50 ppm, ∑Ce/∑Y≥1 andδEu<0.4, and examplifted by Hukeng, 1)enbuxian, Huashan, Dajishan and Huangsha granites;(2) Light REE-enriched type, characterized by∑REE>250ppm,∑Ce/∑Y>6, and examplified by Malage granite;(3) Heavy REE-enriched type, charactelized by ∑REE>250 ppm and ∑Ce/∑Y<0.15, and examplified by Xihuashan, Yinyan and Xishan granites; (4) REE-depleted type, characterized by EREE<50 ppm and examplified by Yashan and Limu granites. These geneses can be intezpreted as caused by different histories jn the formation and evolution of granitic magma. These leatures result from the differences in nature ol source rocks and their initial REE background, degree of partial melting, completeness of deep-seated differentiation in the magmatic chamber and in situ differentiation at higher levels after their emplacement, remelting of underlying crystalline basement and younger granitic rocks which had not been completely consolidated and effects of F, CO2 and other volatile components. A combination of these factots might account for the geneses of Sn/W-bearing granites. |
