大杨树盆地北部九峰山组岩相古地理特征及演化

Characteristics and evolution of lithofacies-paleogeography for the Jiufengshan group in the north Dayangshu basin

运用沉积学理论,结合岩相组合、岩石类型及沉积建造标志,研究大杨树盆地九峰山组沉积体系特征及时空配置关系.结果表明:研究区发育冲积扇、冲积平原、三角洲平原及河流沉积体系.九峰山组下段沉积时期,湖泊体系最为发育,以湖泊体系为中心发育小范围的三角洲平原、冲积平原和冲积扇,物源来自北部及东侧的盆地边缘隆起带;九峰山组上段沉积时期受盆地内火山活动及大兴安岭隆起影响,湖泊体系整体向南退却,三角洲平原、冲积平原及冲积扇体系范围逐渐扩大,为九峰山组最主要的聚煤时期,物源来自盆地两侧及北部隆起地带.该研究为大杨树盆地九峰山组资源勘探提供指导.

Based on the sedimentological theory,the paper researches the sedimentary system and space-time allocation relationship of Jiufengshan formation in the Dayangshu basin according to the analysis of the lithofacies association,the rock type and sedimentary structure.The results show that there are alluvial fan,alluvial plain,deltaic plain and river sedimentary system in the research area.The lake sedimentary system developed extensively during the lower Jiufengshan group.Besides,located the alluvial fan,alluvial plain and deltaic plain are developed around the center lake and the source mainly comes from the north and east of the basin uplift margin.Due to the volcanic activity and the great hinggan mountains uplift,the lake sedimentary system begins to fade away towards the south and the alluvial fan,alluvial plain and deltaic plain sedimentary system have a great wide distribution during the upper Jiufengshan formation.Therefore,this period is the coal forming period of the Jiufengshan formation and the source is from the two sides of the basin and the north uplift area.The research on character and evolution of lithofacies-paleogeography for the Jiufengshan group can be used to guide the coal exploration of the Dayangshu basin.