梅河盆地古近纪梅河组有机质富集规律及沉积演化研究  

Deposition evolution and enrichment pattern of organic matter of the Meihe Formation in the Paleogene,Meihe Basin

作　　者：徐银波[1,2] 柳蓉[1,2] 刘招君[1,2] 孙平昌[1,2] 王建鹏 姚树青[4] 胡晓峰[1,2] 赵汉卿[1,2] 

机构地区：[1]吉林大学地球科学学院,吉林长春130061 [2]吉林大学油页岩与共生能源矿产成矿及勘查开发重点实验室,吉林长春130061 [3]中石化胜利油田西部新区研究中心,山东东营257045 [4]中石化胜利油田地质科学研究院,山东东营257015

出　　处：《煤炭学报》2013年第11期2007-2016,共10页Journal of China Coal Society

基　　金：国家潜在油气资源(油页岩勘探开发利用)产学研用合作创新建设资助项目(OSP/R-01);国家自然科学青年基金资助项目(41302097);吉林省科技发展计划(青年科研基金)资助项目(20090167)

摘　　要：为完善梅河盆地油页岩、煤等能源矿产形成机制,通过对梅河盆地全取芯井岩芯的详细观察,以系统的有机地球化学测试分析为基础,结合本区区域地质特征,研究了梅河盆地梅河组沉积环境演化及有机质富集规律。在梅河组识别出冲积扇、扇三角洲和湖泊3种沉积相,梅河组底部砂砾岩段主要发育冲积扇中扇,下部含煤段为扇三角洲平原和前缘,中部泥岩段则为半深湖—深湖,上部含煤段和绿色岩段分别为湖沼和浅湖沉积,其中煤主要发育在扇三角洲河道间沼泽和湖沼相,而油页岩沉积于半深湖—深湖环境中。梅河组自下而上泥岩中有机质含量呈现出先增加后减少的趋势,有机质类型则由Ⅲ型变为Ⅱ2,Ⅱ1再变为Ⅲ型,有机相也由E—A—E。综合研究表明,由构造演化和古气候引起的基准面、沉积环境、有机质供给和保存条件的变化,导致沉积的泥岩中有机质丰度和类型明显不同,在盆地初始沉降阶段中期和萎缩阶段初期,稳定浅水地带高等植物大量繁殖,同时陆源碎屑供给较少,水底具有良好的保存条件,易于形成煤层沉积;而在盆地最大沉降阶段,稳定深水区域,伴随着较高的湖泊生产力和良好的保存条件,形成油页岩沉积。Based on the detailed observations of the whole core, bulk of organic geochemical analysis, and combined with regional geological characteristics, the evolution of depositional environments and enrichment pattern of organic matter of mudstone of the Meihe Formation in the Meihe Basin was studied, and this will be enriched the theory of oil shale and coal metallogenic mechanism of the Meihe Basin. Three types of sedimentary facies were identified in the Meihe Formation including alluvial fan, fan-delta and lake facies. Mid-fan subfacies of alluvial fan is developed in the bottom of Sandy-Conglomerate Member, and fan delta deposited in the Lower Coal-bearing Member. In the middle Mudstone Member, the mainly depositional environment is semi deep-deep lake. Lacustrine bog and shallow lake are developed in the Upper Coal-bearing Member and the Green-rock Member separately. It should be noted that, oil shaledeveloped in the semi deep to deep lake, and coal layers deposited in the swamp. The organic matter content in mud- stone shows a decreasing trend after increasing upward, meanwhile the type of kerogen changes from type III to II2 and II1 ,then becomes to type III,and this caused the organic facies changes from E to A,and becomes E finally. Compre- hensive studies show that, the base level, depositional environment evolution, organic matter supply and preservation conditions caused by tectonic and paleoclimate evolution result in different types and abundance of organic matter in mudstone. Due to the limit terrestrial debris supply,good preservation condition and explosion of higher plants,it is fa- vorable for coal seam to occur in the stable shallow water area in the mid-stage of initial subsidence and the beginning of the basin shrinkage stage. While with the high lake productivity and good preservation conditions, oil shale deposited in the stable deep water area during the largest basin subsidence stage.

关 键 词：有机质 富集规律 沉积演化 古近纪 梅河盆地 

分 类 号：P539[天文地球—古生物学与地层学]