Origin of postcollisional magmas and formation of porphyry Cu deposits in southern Tibet

In contrast, to the west of ~88°E, subduction of the Indian plate has remained flat to the present day, preventing incursion of hot asthenosphere. Consequently, cooler conditions in the deep Tibetan lithosphere resulted in limited crustal melting and the production of only small volumes of high-Sr/Y granitic magmas. Trachytic melts ascending from the underthrust Indian or Tibetan plate were able to pass through the cooler lower crust and erupted in greater volume at surface, whereas only small volumes of high-Sr/Y granitoid magma were generated and are not associated with significant PCD mineralization.