摘要
昆阳群地层岩石极低级变质作用的主要特点 :碎屑状绿泥石 白云母 (绢云母 )堆垛集合体发育 ,且多平行层理定向排列 ;个别堆垛集合体见有明显的弯曲或膝折现象 ,表明经受平行层理的压缩作用。根据堆垛集合体、层理及早世代水力破裂 充填石英微细脉体间关系 ,认为极低级变质作用是区域变形构造 热事件之前的产物 :变质温度在 15 5～ 35 0°C之间 ,变质级、地层时代及岩层在地层柱中的位置渐趋一致 ,与区域变形强度缺乏谐调关系。
The main characteristics of very low metamorphism of Kunyang Group are as follows. The clastic chrolite-muscovite(sericite)stack is developed, parallel to the bedding. And a few stacks are evidently curved, which shows the compression parallel to the bedding. According to the relation-ship between stack, bedding and hydraulic fractured-filled quartz veinlet, the very low metamorphism is regarded as the product before the regional deformation structure-thermal event. Its metamorphic temperature is from 155°C to 350°C. And the metamorphic grade is gradually consistent with the formation period and location in strata column of rock, inharmonious with the regional deformation intensity. These characteristics show that they belong to the burial metamorphism in a rift environment under extensional setting of the earth crust.
出处
《云南地质》
2001年第4期369-375,共7页
Yunnan Geology
关键词
极低级变质作用
裂陷槽
昆阳群
滇中
岩石
Very Low Metamorphism
Taphrogeosyncline
Kunyang Group
Central Yunnan
