摘要
糜棱岩是在构造应力作用下发生明显塑性变形、具有明显的运动指向标志、集中呈带状产出的构造岩。根据实用性和目的性建立庆棱岩的描述性和成因两个分类系列。在描述性分类中，将糜棱岩分为细粒糜棱岩、中粒糜棱岩和粗粒糜棱岩３个类型。各类型再进一步分为均匀、均匀碎斑和非均匀碎斑３个亚类。在成因分类中，将糜棱岩分为低温脆一韧性糜棱岩、中温韧性糜棱岩和高温超韧性糜棱岩３个类型，再分为低温石英脆一韧性糜棱岩、中温石英韧性糜棱岩、中温石英一斜长有韧性糜棱岩及高温斜长石一钾长石超韧性糜棱岩、高温钾长石一辉石超韧性糜棱岩、高温辉石－橄榄石超韧性糜棱岩６个亚类。
The authors consider that mylonite is one type of tectonite which shows obvious plastic deformed features, contains marks of movement-sense and outcrops in narrow belt.Mylonitic texture and grain-size reduction should not be treated as the main criteria for recognizing mylonite. Blastomylonite is an indeterminate term causing confusion in its meaning and should be abandoned in use. It is proposed that two systems of classification of mylonite, i. e., descriptive classification and origin classification, should be established. In the descriptive classification, mylonite is divided into three categories, finegrained mylonite, medium-grained mylonite and coarse-grained mylonite mainly according to the grain-size of matrix mineral. Every category could be then divided into three subcategories by adding 'homogeneous', 'homoclastic (homoporphyroclastic)' and 'heteroclastic(heteroporphyroclastic)' to the mylonite name respectively on the basis of investigating the distributional status and size-difference between porphyroclasts. In the origin classification, mylonite is first divided into low-temperature brittle-ductile mylonite, middle-temperature ductile mylonite and high-temperature ultraductile mylonite, and then further divided into low-temperature quartz brittle-ductile mylonite, middle-temperature quartz ductile mylonite, middle-temperature quartz-plagioclase ductile mylonite, high-temperature plagioclase-Kf-feldspar ultraductile mylonite, high-temperature Kf-feldspar-pyroxene ultraductile mylonite and high-temperature pyroxene-olivine ultraductile mylonite.
出处
《现代地质》
CAS
CSCD
1994年第1期73-78,共6页
Geoscience
基金
国家自然科学基金
关键词
糜棱岩
构造岩
麻粒岩相
分类
mylonite, tectonite, granulite facies, classification of mylonite
