MINERALOGICAL AND PETROLOGICAL CHARACTERISTICS OF THE ECLOGITE FACIES ROCK COMBINATION AT MAOWU AREA IN THE SOUTH DABIE OROGENIC BELT

Being different from other eclogites in the Dabie orogen,the eclogite facies rock combination occurring in Maowu area in the southern Dabie orogen contains enstatites,so far there is no report about this. The eclogite facies rock combination includes two-mineral eclogite,enstatite eclogite,garnet orthopyroxenite, garnet pyroxene peridotite and enstatite mylonite.They are probably formed by eclogite facies metamorphism of magmatic protoliths.There are pure enstatite occurring in the rock combination.The clinopyroxenes in the eclogites are relatively Na_2 O low.Except the two-mineral eclogite,the garnets are rich in pyrope,the pyrope end member reaches 71.8%.According to the chemical compositions of the eclogites,the eclogites can be divided into two types:a.Fe-Ti type;b.Mg-Cr type.The rock forming pressure is about 18-26kb,and the temperature is about 931-1076.So they belong to high-temperature eclogites.The eclogite facies rock combination was quickly exhumed to shallow crust level along deep shear zone,and showes no overprinting metamorphism induced by deep level pressure reduction.