Geochemical features and tectonic setting of peraluminous granite in the Lhozag area,southern Tibet

Peraluminous two-mica(muscovite)monzogranite and tourmaline monzogranite of varying size and occurrence are distributed in Lhozag and areas to its south.These rock bodies were em placed in the Miocene and constitute the eastward extension of the Higher Himalaya granite belt.They are characterized by the high-Al and low-Fe and-Mg composition and high Sr and O isotope ratios.Geochemical study shows that they are the product of anatexis of argillaceous rocks and fractional crystallization of magmas.Peraluminous granite was emplaced along a detachment zone in the setting of larger-scale extensional de-tachment in the stage of post-collisional orogeny.The peraluminous granite formed in the late stage of ductile activity of the southern Tibetan detachment system.It is a typical post-collisional peraluminous gran-ite.