陕西省中侏罗统延安组层序地层格架与煤层形成  

Middle Jurassic Series Yanan Formation Sequence Stratigraphic Framework and Coal Seam Formation in Shaanxi Province

作　　者：王东东[1] 邵龙义[1] 李智学[2] 任海香[2] 李明培[1] 田野[1] 贺丹[2] 

机构地区：[1]中国矿业大学(北京)地球科学与测绘工程学院,北京100083 [2]陕西省煤田地质局勘察研究院,陕西西安710054

出　　处：《中国煤炭地质》2011年第8期22-27,共6页Coal Geology of China

基　　金：国土资源大调查(1212010633901);国家科技重大专项(2011ZX05009-002)项目共同资助;河南省生物遗迹与成矿过程重点实验室开放基金(OTMP1008)

摘　　要：在系统收集陕西省中侏罗统延安组野外露头、钻井、测井、古生物等资料的基础上,对其沉积环境、层序地层格架进行研究,并分析了煤层的沉积特征。研究认为延安组发育的沉积体系有河流体系、三角洲体系及湖泊体系;研究区南部黄陇地区在整个延安组沉积期均发育河流体系;中、北部地区在延一段早期和延五段沉积期以河流沉积为主,三角洲体系主要发育在延一段中晚期-延四段沉积期,主要分布在西北部榆林-神木-府谷和定边-靖边-吴旗地区;湖泊体系主要发育在延一段中晚期-延四段沉积期,主要分布在安塞-志丹-甘泉地区;在研究区的沉积体系中,煤层主要发育在河流泛滥平原沼泽和三角洲平原沼泽环境。通过对延安组关键层序界面的识别与追踪,可将延安组划分为3个三级层序和9个体系域,3个层序在研究区西部和北部保存较全,向东、南方向层序III的保存程度逐渐变差,到南部黄陇地区仅残存层序I和部分层序II的地层;在层序地层格架中,厚煤层主要发育在湖侵体系域晚期(最大湖泛面附近)、早期和高水位体系域中晚期。Based on systematic collection of Middle Jurassic Series Yanan Formation outcrop,borehole,well logging,paleontologic data in the Shaanxi Province,carried out the formation＇s sedimentary environment,sequence stratigraphic framework studies and analyzed coal seam sedimentary features.The study considered that,sedimentary systems in Yanan Formation have fluvial,deltaic and lacustrine systems.In the Huangling-Longxian region in southern study area,fluvial sedimentary system was developed during the entire Yanan Formation depositional stage,while in middle and northern study area,mainly during the early First Member and Fifth Member depositional stages;deltaic sedimentary system mainly developed during the middle and late First Member to Fourth Member depositional stages and distributed in the northwestern Yulin-Shenmu-Fugu and Dingbian-Jingbian-Wuqi regions;lacustrine sedimentary system mainly developed during middle and late First Member to Fourth member depositional stages,and mainly distributed in the Ansai-Zhidan-Ganquan region.In the sedimentary systems,coal seams are mainly developed in fluvial flood plain bog and deltaic plain bog environments.Through identifying and tracing of key sequence boundaries in Yanan Formation,3 third-order sequences and 9 systems tracts have been partitioned,the 3 sequences have rather well preserved in western and northern study area,while in southern study area Huangling-Longxian region,only sequence I and part of sequence II remained.In the sequence stratigraphic framework,thick coal seams were developed mainly during late stage of lacustrine transgressive systems tract（near maximum lacustrine-flooding surface）,early stage and middle-late stage of highstand systems tract.

关 键 词：沉积相 层序地层 煤层形成特征 延安组 陕西省 

分 类 号：P539.2[天文地球—古生物学与地层学] P534.52[天文地球—地质学]