Discovery of granulite in the Mianxian-Lueyang suture zone, Mianxian area and its tectonic significance.

Mafic granulite lithoblocks, found at many localities near Xujiaping Villag e of Caimahe Town in Mianxian County, occur in Mian-Lue suture zone as a li thoblock. Its metamorphic mineral assemblage is Cpx+Gt+Pl (An30)+Qz+ Rut. T emperature is between 657 degrees C and 772 degrees C calculated by thermom eter of Ellis et al. Pressure ranges from 0. 82 GPa to 1. 17 GPa based on b arometer by Newton et al.. Corrected values are respectively 0. 97 GPa and 1. 32 GPa. In thin-section , retrograde reaction in the mafic granulite is observed as Gt + Cpx = Hb + Pl. This reflects clockwise P-T-t path and meta morphic process with isothermal decompression, indicating collisional histr oy along Mian-Lue suture zone of Qinling orogen.