THE FEATURES OF THE GLAUCOPHANE SCHIST IN THE SOUTHERN PART OF THE LANCANG JIANG METAMORPHIC BELT

This paper preliminarily summarizes the metamorphic rocks and the restoration of their original rocks in the southern part of the Lancang Jiang metamorphic belt in the Huiminxiding region. The glaucophane greenschist facies series is distinguished. According to the appearance of the low-temperature and high-pressure minerals such as glaucophane, barroisite, phengite, riebeckite and stilpnomelane and the. detailed mineralogical study of 3T-type phengite, the temperature and pressure of the glaucophane greenschist facies series are determined to be 200—250℃ and 6—7 kb respectively, the geothermal gradient 12℃/km, and the age of the low-temperature highpresure metamorphism 240—260 m.y.P.Thus it is thought that the Lancang River metamorphic belt is situated in the subduction zone of a plate.