湘中地区煤系变形及煤变质作用特征分析

西安科技大学 地质与环境学院,陕西 西安 710054

煤系变形; 变质作用; X射线衍射分析; 扫描电镜分析; 煤化学结构

Coal seam deformation and metamorphism characteristics in central Hunan
LI Huan-tong,LI Jian-zhuo,LI Yang,LIANG Hui,LI Lian-hai

(College of Geology and Environment,Xi'an University of Science and Technology,Xi'an 710054,China)

coal deformation; metamorphism; X-ray diffractogram; scanning electron microscope; coal chemical structure

DOI: 10.13800/j.cnki.xakjdxxb.2017.0618

备注

湘中地区测水组、龙潭组煤在强烈的岩浆热活动的影响下,叠加在区域变质作用背景之上,同时多期次、多层次的构造变形,使煤化作用过程复杂化。采用煤质分析、X射线衍射、扫描电子显微镜等实验手段,对湘中地区测水组、龙潭组煤系的煤化学组分及结构特征、显微构造分析,探讨煤系变形及煤变质作用特征。结果 表明:煤变质带总体为北东向展布,在规模较大的含煤向斜周缘呈反向环带,呈反希尔特定律现象; 层滑断裂引起的应力集中叠加岩浆热作用使局部地区煤变质程度增高,煤的物理性质、结构改变,形成构造煤; 由于新化寒婆坳向斜天龙山岩体的构造-热耦合作用,煤中常见有镶嵌结构,且煤大分子结构趋向有序化,面网间距d002减小,芳香层片堆砌度增大,具有动力变质作用的典型结构特征,高煤级煤逐渐过渡为隐晶质石墨,由细小鳞片组成集合体,粒径在50~250 nm.

Coupling effect between magmatic thermo-metamorphism and plutonic metamorphism-Ceshui and Longtan Formation in Central Hunan suffer multi-phase,multi-layers,mtulti-tectonic-thermal events during Indo China-Yanshanian period,which result in more complex coalification process.This paper discusses chemical composition,molecular structure,microstructure phenomena to deepen the knowledge for the correlation of coal deformation and metamorphism with structural environment in Central Hunan by coal quality analysis,XRD and SEM methods.The results show that:the distribution of coal metamorphic belt shows NE general,but the evolution of coal metamorphic belt in major coal-bearing syncline edge presents different evolution which changes from anthracite coal to metabituminous coal,which has the phenomenon of anti-Hilt law; seam-gliding structure generated stress concentration and magmatic thermo-metamorphism result in the increase of coal rank during coalification,the physical properties and texture has changed to form tectonic coal simultaneously.Because of structure and thermal coupled interaction in Xinhua Hanpo'ao syncline,and embedded structure is common in high rank coal,moreover its molecule structure shows a tendency to ordering,d002 value decreased,result in increasing the stack height of aromatic plane,which present typical characteristics of dynamometamorphism; High rank coal resolved itself into aphanitic graphite which is characterized by graphite flakes,and the crystallite size is from 50 to 250 nm.