GRANITOIDS RELATED TO WESTERN YUNNAN (DIANXI) TIN DEPOSITS AND THEIR METALLIZATION
Luo Junlie (B■reau of Geology and Mineral Resotirces of Yunnan Province, Kunming, Yunnan Province)
The Southeast Asia tin metallogenic domain is the southward extension of the Sanjiang tin metallogenic domain in Southwest China. The western belts and central belts of the two domains are correspondingly connected and comparable with each other, but their eastern belts are not comparable. The Dianxi tin deposits are the main part of the Sanjiang tin metallogenic domain, and their regional settings are related closely to the evolution of Paleo-and NeoTethys tectonics. This paper has made a detailed analysis of the granitoids in TengchongLianghe area and for the first time divided them into three rock groups, eight superunits, twenty-eight units and a number of intrusive bodies. In the light of petrologic evolution, geochemistry, assemblages of individual minerals and accessory minerals, REE and isotopic composition, spatial distribution and ore potentiality, the paper has studied the units and superunits. A new scheme is put forward for the classification of primary tin deposits and the metallogenic series. In addition, some preliminary conclusions of the Dianxi tin deposits are drawn which show distinctive regional features.