滇西澜沧变质带中白云母的研究及其地质意义

本文以滇西澜沧变质带中最为广泛分布的造岩矿物—白云母为对象，详细研究和 分析了其成分、多型类型及ba值等，探讨了白云母的发育规律。研究结果表明，本带中绝大多数白云母为多硅白云母，且为3T+2M,型，与蓝闪石共生的则以3T多硅白云母为主。此外，斓沧变质 带经历了蓝闪石片岩亚相的高压变质作用，与古特提斯构造演化密切相突，并可与世界著名的高 压带对比。

A Study of Muscovites from the Lancang Metamorphic Belt in Western Yunnan and Its Geological Significance

This paper is devoted to the study of muscovites, the most extensively distributed rock-forming minerals in the Lancang metamorphic belt of western Yunnan. Their composition, polytypes and bo values are analysed and examined in detail, and theca regularity of their growth is tentatively discussed. It is shown that the overwhelming majority of muscovites are phengites of 3T+2M1 type whereas those associated with glaucophane are mainly 3T phengites. Studies also indicate that the Lancang metamorphic belt underwent high-pressure metamorphism of blue schist subfacies and was closely related to the evolution of paleotethys. Therefore, it can be correlated9 with other well-known high- pressure belts i n the world.