摘要
针对滇黔北威信凹陷晚二叠世含煤岩系的“海相-海陆过渡相-陆相”三相变化地带,利用地层剖面上的沉积构造、岩石组合、古生物特征等沉积相判别标志分析研究区的沉积环境及其空间演化,并总结煤质变化规律。在此基础上,通过识别层序与体系域关键界面,建立研究区晚二叠世含煤岩系的层序地层格架,充分讨论研究区厚煤层在层序地层格架下的聚煤规律。研究区自西向东依次为河流冲积平原体系、三角洲-潮坪体系及碳酸盐岩台地体系,成煤环境主要为河流冲积平原中的泛滥盆地河漫沼泽和三角洲-潮坪沉积体系中的上三角洲平原;厚煤层在层序地层中的位置与古地理背景有关,研究区C15,C19煤层形成于最大海泛面附近,C25煤层形成于初始海泛面附近;根据煤质变化规律和煤厚变化特征,在研究区西部的彝良-盐津一带有寻找优质煤炭资源的潜力。
Sedimentary structures,petrological assemblages and paleontological features from the cross section in the Weixin Sag are studied in order to analyze the sedimentary environment,special evolution and summarize the change regularity of coal quality in the facies variation area of marine facies-land and sea transition facies-land facies.On the basis of identification of sequence and system tract interface,the framework of sequence stratigrapy of late Permian coal-bearing layer is established and the coal accumulation law under the sequence stratigrapy framework is discussed. From the west to the east,the sedimentary facies in the area are in the order of river alluvial plain depositional system,delta-tidal flat depositional system and carbonate platform depositional system respectively.The coal-forming environment is mainly the overbank swamps in the river alluvial plain and the upper delta plain in the delta-tidal flat depositional system.In sequence stratigraphy,the position of thick coal seam is related to paleogeographic background.The C15 and C19coal seams in the study area is formed near the maximum flooding surface,and the C25 coal seam is formed near the first marine-flooding surface.According to the change rule of coal quality and coal thickness,it is proposed that the Yiliang-Yanjin region has the potential of high quality coal resources.
作者
文俊
任光明
庞维华
卢君勇
张鹏
周洋
Wen Jun;Ren Guangming;Pang Weihua;Lu Junyong;Zhang Peng;Zhou Yang(No.207 Geological Team of Sichuan Bureau of Geology & Mineral Resources,Leshan 614000,China;Chengdu Institute of Geology and Mineral Resources,China Geological Survey,Chengdu 610081,China)
出处
《矿物岩石》
CAS
CSCD
北大核心
2019年第3期85-94,共10页
Mineralogy and Petrology
基金
中国地质调查局项目《乌蒙山区地质矿产综合调查》（编号：DD20160019)
关键词
威信凹陷
晚二叠世
含煤地层
沉积环境
层序地层
聚煤规律
Weixin Depression
late Permian
coal-bearing formation
sedimentary environment
sequence stratigraphy
coal accumulation
