Geochemistry and geodynamics of the strongly peraluminous granites in Darying,Qiangtang,Xizang

Strongly peraluminous two-mica alkali-feldspar granite, muscovite alkali-feldspar granite and tourmaline muscovite alkali-feldspar granite recognized, for the first time, in Darying, central Qiangtang are characterized by high fractions of SiO₂, Al₂O₃ and K₂O, high Al, low Mg, low Fe, A CNK ratios >1.1, indicating the typical muscovitebearing strongly peraluminous granites.ΣREE values range between (10.65-100.02)×10^-6 and The REE distribution patterns exhibit marked negative Eu anomalies.The high field strength elements Nb, P and Ti display negative anomalies, while the macro-ionic lithphile elements Rb, Th and Y display positive anomalies. The magma sources may be originated from clay-rich sources, representing the products of partial melting of mature continental masses. The plot of chondrite-normalized trace element patterns, R₁-R₂ diagram, Rb-Hf-Ta discriminant diagram, Rb-(Yb+Nb)and Rb-(Yb+Ta)diagrams indicate that the Darying granites are assigned to the syn-collisional granites, and have recorded the magmatic history of the Gangmar Lake structural zone during the collisional stages. The discovery of the strongly peraluminous granites in Darying has contributed to important geological information for the exploration of geological and tectonic evolution of the Qiangtang block, Xizang.