Tin and tungsten:potential dominant mineral species in the Gangdise belt, Xizang

The giant Gangdise compound magmatic belt in Xizang is known as another important metallogenic zone in China, in which copper, lead, zinc, gold and iron are hosted as dominant mineral species. In addition, tin and tungsten should also be potential dominant mineral species in the Gangdise belt. The frequent and severe plate movements during the Mesozoic and Cenozoic in the belt resulted in the formation of the arc granites, collisional orogenic granites and postorogenic granites. The collisional orogenic granites were originated from the partial melting of the continental crust, and thus have the metallogenic specialization of tin and tungsten. These granites coexist with the arc granites in the southern, central and northern Gangdise granite belts including more than 40 granite masses in each of the granite belts dated at the Cretaceous and Palaeogene.On the basis of petrographic, lithochemical, geochemical signatures of REE and trace elements, the Qiboxiari, Sangba, Yatangna, Lubagang, Yunong and Gengzhang tin-forming granitic masses are recognized in the crust-melted granitic belts cited above. The source beds of tin and tungsten include Nyainqentanglha Group Complex, Lower Palaeozoic, Middle -Upper Jurassic and Lower Cretaceous strata on the basis of the trace element abundances. The tin and tungsten mineralization is well documented by the features of multistage tectonic activities and plastic and brittle deformational, traces and exploration of the existing tin and tungsten deposits (mineralized localities)_in the Gangdise belt.