Department of Geology��Northwest University��Xi’an 710069��China

The Foping granulites are located in the South Qinling Orogenic Belt�� The origin of these rocks plays an important role in understanding the tectonic interaction between the Qinling Orogen and the Yangtze Block during Mesozoic time�� This work carried out systematic mineralogical and geochemical investigations on the Foping granulites by employing electron probe��infra- red spectrum��and whole- rock chemical analytical methods�� The results indicate that the granulites are primarily felsic in composition and composed mainly of plagioclase��quartz�� almandine��pyrope��hypersthene��and minor biotite and calcic amphibole�� The granulites are characterized by en- richment in light rare earth elements and large ion lithophile elements�� and depletion in high field- strength element�� with significant negative anomalies of Nb and Ta�� These features are indicative of subduction- related geochemical signature�� In combination with geological and radiometric age data�� this study suggests that the formation of the protoliths of the Foping granulites was associated with the northward subduction of the Mianlue oceanic lithosphere be- neath the South Qinling Block�� In the Middle- -Late Triassic��the continent- continent collision between the South Qinling and the Yangtze blocks resulted in the granulite- facies metamorphism that led to the formation of the Foping granulites��