摘要
川南地区晚二叠世峨眉山玄武岩韵律性旋回明显,局部夹煤层,是攀西裂谷中岩浆喷溢形成的岩体,研究认为本区玄武岩是C23-1以下含煤地层的"相变"。均衡作用和"坍塌"效应引发地壳下沉,与玄武岩岩体密切相关,从而控制了不同时期聚煤基底地形;本区晚二叠世属潮坪聚煤环境,是在总的海侵背景条件下,由海侵、基底升降和聚煤速率共同作用来造就聚煤可容空间,本区正向的同沉积构造,即基底上升,能协调三者造就有利的聚煤可容空间;"古蔺—温水正向同沉积构造","筠连蒿坝正向同沉积构造"为潮坪聚煤奠定了有利的地形条件,成为聚煤中心。该区上二叠统煤层主要属高阶煤,推测与幔源物质集聚活动有关,受深部高温幔源物质热能传导作用的影响,储蓄热能成为高温异常区,是高阶煤形成的主要原因。
The Late Permian Emeishan basalt rhythmic cycle features in southern Sichuan are obvious, locally intercalated with coal seams. The rock mass was formed by magmatic outpouring. The study reckoned that the basalt in the area is the ＂facies change＂ of coal-bearing strata under the C23-1. The isostatic compensation and ＂collapse＂ effect initiated the earth crust subsidence; it is closely related to basalt rock mass, thus controlled base topography during different periods. The Late Permian tidal flat coal accumulation environment was under the overall marine transgression background brought up coal-accumulative accommodation space through combined actions of marine transgression, basement elevation, subsidence and coal-accumulation rate. The area＇s positive synsedimentary structure or the basement elevation can coordinate the three actions brought up favorable coal-accumulative accommodation space. The Gulin -Wenshui and Junlian-Haoba positive synsedimentary structures have established favorable topographic condition for tidal flat coal accumulation and turned into coal-accumulative center. The Upper Permian coals in the area belong to high rank coals; it is speculated on the result of mantle-derived material aggregation, impacted by deep high temperature mantle-derived material heat conduction and become high temperature anomalous area, thus the main reason of the high rank coals formation.
出处
《中国煤炭地质》
2010年第2期14-18,共5页
Coal Geology of China
关键词
峨眉山玄武岩
含煤建造
均衡作用
同沉积构造
相变
聚煤带
变质
Emeishan basalt
coal-bearing formation
isostatic action
synsedimentary structure
facies change
coal-accumulative zone
metamorphism
