Magma-mixing genesis of quartz monzodiorite in the Weiya Xinjiang

There wildly occurs magma mixing in the Weiya vanadium-bearing titianomagnetite ore district,which evidenced by not only lots of diorite enclaves in granitoid rocks,granitoid enclaves in diorite and dispersion each other,but also forming a mixing product in the contact zone of granite and diorite:magma mixed rocks.Based on comparison of field characteristics,lithology and mineralogy, it is found that the quartz monzodiorit rockbody in the middle part of the ore district is identical petrography with the magma mixed rocks and thus the rockbody might belong to magma-mixing genesis.All rock types present typical magma mixing characteristics in petrography and mineral chemistry.There are wide spread disequilibrium mineral textures in these rocks such as rapakivi texture of Kf (potassium feldspar),circum-phenocrast structure,acicular apatite texture,glomerogranular crumb structure by hornblende and biotite,plagioclasecrystalloblastwith a lot of capture crystals.Plot data of main oxides versus SiO_2(wt %)from plagioclase and hornblende compose of well linearity similar to Hake diagram of bulk-rock analysis.Composition of essential rock-forming minerals and huge Kf phenocrast section indicate that exchange of the chemical compositions exist in magma mixing.It is suggested by composition of biotite that the magma mixing in this area is derived from crust-mantle mixing source.