Variscan terrane of deep-crustal granulite facies in Yushugou area, southern Tianshan

The Yushugou terrane of deep-crustal granulite facies in southern Tianshan consists of two parts, granulite and metaperidotite. The whole terrane is a metamorphism of (high-pressure) granulite facies, and typical mineral asso ciations are: Gt-Cpx-Pl-Tit-Ilm(+/- Qz) (silica-saturated and oversaturated mafic rocks), Ct-Ky (pseudomorph)-Pl-Ru-Ilm +/- Qz (metapelitic rocks) and Spi-Opx-Cpx-Ol (meta-ultramafic rocks). The peak-stage P-T conditions are 795-964 degrees C, 0.97-1.42 GPa, which are obtained with mineral chemistry , assemblage analyses and P-T estimation. The Sm-Nd isochron age of peak-st age metamorphic minerals is (315 +/- 3.62) Ma. M of these indicate that the terrane is a deep-crustal body, which subducts to the depth of 40-50 km in the middle late-Paleozoic, undergoing metamorphism of (high-pressure) gran ulite facies, and exhumed again to the surface by tectonic uplifting.