中天山彩霞山一带麻粒岩的发现和热力学研究

Discovery and thermodynamics of granulite in the Caixia mountain,Xinjiang,China

报道了在新疆中天山彩霞山一带元古代地层中发现麻粒岩。根据麻粒岩的主要组成矿物单斜辉石、斜方辉石、黑云母、斜长石、角闪石的电子探针分析结果，重点讨论了各主要造岩矿物的形成条件，并对麻粒岩形成的温压条件进行了初步计算。结果表明：麻粒岩形成经过两个阶段，麻粒岩形成于0．88～1．17GPa，880～890℃条件下；角闪石一斜长石退变组合形成温度620～640℃，压力0．30～0．37GPa。

This paper presents the granulite facies metamorphic rock found for the first time in the Caixia mountain, Xinjiang. The mineral assemblages of the granulite are clinopyroxene, orthophyroxe, biotite, plagioclase, amphibole, quartz. According to the results of mineral electron probe analyses, the formation conditions of granulite are discussed and P-T conditions are calculated. The results show that the formation of granulite have two stages： early granulite-facies rocks formed under the conditions of 0. 88 ～ 1. 1 GPa and 880 ～ 890℃; the later amphibole-facies retrogressive metamorphism paragenesis formed under the conditions of 0.30～0.37 GPa and 620～640℃, belonging to a typical low-pressure type.