四川资中铁佛场普查区须家河组沉积环境与聚煤作用

Depositional Environment and Coal Accumulating in Xujiahe Formation, Tiefochang Reconnaissance Area, Zizhong, Sichuan

以大量钻孔岩心资料为基础,对资中铁佛场普查区须家河组沉积环境进行了分析,在须家河组共识别出4个三级层序,分别对应一段、二—三段、四—五段、六段,其层序特点为:低位体系域主要为河道砂岩沉积,几乎没有煤层发育;湖侵和高位体系域主要发育湖泊三角洲相,在滨岸沼泽和分流间湾环境成煤,且高位体系域煤层发育相对较厚、较多。研究认为区内主要可采煤层(高炭、下元炭煤层)形成于滨岸沼泽和受河流控制为主的湖滨三角洲环境。

Based on a mass of borehole core data,analyzed depositional environment of the Xujiahe Formation in Tiefochang reconnaissance area,Zizhong.4 third order sequences have been recognized in the formation,corresponding to members Ⅰ,Ⅱ-Ⅲ,Ⅳ-Ⅴ and VI respectively.The sequential characteristics are： lowstand system tract is mainly channel sandstone deposit,next to nothing coal seam developed;lacustrine transgression and highstand system tracts mainly developed lacustrine deltaic facies,in onshore bog and interdistributary bay environments coal accumulated,coal seams in highstand system tract are relatively more in number and thicker.The study considered that the main mineable coal seams（Gaotan and Xiayuantan） were deposited in onshore bog and fluvial-dominated lake-shore delta environments.