THE GENERAL CHARACTERISTICS OF SHIGU METAMORPHIC BELT IN WESTERN YUNNAN PROVINCE
滇西石鼓变质带基本特征

Shigu Metamorphic Belt is situated in Northwestern Yunnan Province, which is a low to middle grade regional metamorphic belt and has been divided into chlorite, biotite, almandine, staurolite, kyanite and sillimanite zones.The equilibrium association of andalusite-kyanite characteristics of the Shigu Metamorphic Belt indicates that the P-T curve of regional metamorphism is evolved along the line of facies transition between andalusite and kyanite and pass roughly through the three facies point of Al_2SiO_5, and is belong to the low to middle pressure facies series. The main metamorphic period of Shigu Metamorphic Belt is considered as Late Hercynian movement, because an age of 258 Ma has been obtained by K-At isotopic method. The Shigu Metamorphic Beltk is situated in south of Jinsha River Tectonic Belt. It is different from those of Changshan Mountain Group and Ailaoshan Moutain Group, because both of latter have developed extensive dynamic metamorphism, but Shigu Metamorphic Belt is considered as a regional progressive metamorphic belt. It is not possible that the Jinsha River Tectonic Belt is continuous with Ailaoshan Mountain Tectonic Belt.