GEOLOGICAL AND GEOCHEMICAL CHARACTERISTICS OF INTERMEDIATE-ACID INTRUSIVE ROCKS IN ALTYN AND EAST KUNLUN OROGENIC BELT AND THEIR SIGNIFICANCES

Based on the 1∶250 000-scale regional geological mapping in the north of Qinghai-Tibet Plateau and contrasting the intermediate-acid intrusive rocks in the Altyn and eastern Kunlun orogenic belt,regarding of geology,petrology and geochemistry.The results show that the rock type,assemblage of rock types,rock era,magma series,source of magma and geodynamic setting can be contrasted completely.It is indicated that S-type granite in the former Jinning and Jinnin age was fromed by partial or cyclic melting of adulthood TTG continental crust in the collision geodynamic setting probably,and I and A-type granites in caledonian and variscan,presumably in a thinning of continental lithosphere or continental rift dynamic seting,may be derived from magma which was fromed by partial melting of lower crustal rocks intruded by mafic-ultramafic magma from mantle.The magma may be derived from the lower crust of vice-metamorphic eclogite phase and granulite phase.On the basis,combined with previous research,it is proposed that the basements of the Altyn and East Kunlun orogenic belt belong to the same ancient land system.