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本文报道了云南省境内发现的榴闪岩。在双江县勐库一带进行的1∶5万区域地质调查初步将前人厘定的湾河蛇绿混杂岩带向北延伸了20 km,并在其中发现了多个榴闪岩形成的构造透镜体。榴闪岩坚硬致密,石榴石呈中细粒状散布在角闪石中,部分呈细粒条带状产出,显示了原始的火成堆积结构。从现有的多期退变质矿物组合大致可以推断出变质峰期的矿物组合可能为:绿辉石+石榴石+金红石+石英。该榴闪岩在产出的区域构造位置、岩石类型上都可与藏东八宿地区的退变质榴辉岩进行对比。这一发现为滇西地区特提斯构造演化提供了更多的约束条件。
This paper reports the discovery of the marlite in Yunnan Province. The 1: 50000 regional geological survey carried out in Mengku area of Shuangjiang County tentatively extended the predecessor’s Wanhe ophiolitic mélange zone northward by 20 km and discovered a number of tectonic lenses body. The garnet is hard and dense. The garnet is finely grained in the hornblende and is partly finely banded and shows the original pyroclastic structure. From the existing multi-stage retrograded metamorphic mineral assemblages, it can be inferred that the metamorphic peak mineral assemblage may be: omphacite + garnet + rutile + quartz. The amphibolite can be compared with the retrograded eclogites in the Baxu area of eastern Tibet in terms of regional tectonic positions and rock types. This finding provides more constraints for the Tethyan tectonic evolution in western Yunnan.