摘要
本文主要应用沉积体系及层序地层分析的思路和方法,利用大量的野外露头及钻孔资料将侏罗系延安组第Ⅱ成因地层单元解析为3个低级别建造块——A、B和C亚单元;以亚单元为单位,在三维空间内识别了三角洲-湖泊沉积体系的多种成因相及组合,重建了体系域,总结了体系演化的规律性;对聚煤作用进行了成因探讨。
The genetic stratigraphic unit Ⅱ of Jurassic Yan' an Formation in Shenmu district of Ordos Basin consists of three subunits(i. e. subunits A,B and C),which belong to the delta-lacustrine de-positional system. The genetic facies of the system consist in three associations : delta plain association (including distributary channel, abandoned distributary channel, natural levee, overbank deposits, small lake on delta plain,interdistributary bay,crevasse splay,crevasse delta,crevasse channel and swamp), delta-front association (including mouth bar, subaqueous distributary channel, subaqueous levee and subaqueous overbank deposits), pro-delta deposits and open lacustrine deposits. The deposi-tional system tract of subunit A consists of four deltaic lobes,that of subunits B,C of three and four deltaic lobes respectively. The main resource area of deltaic lobes distributed along NE-SW,is located in the east part. Each subunit is composed of transgressive event in the early stage,and the deltaic progradation event in the late stage. From subunit A to subunit C,the characteristics of evolution of depositional system are as follows-the smaller the transgressive scale, the stronger the deltaic progradation process and coal-forming. When deltaic lobes were abandoned, the coal-forming began. The best coal-forming realm is the abandoned deltaic plain,the better interdelta bay,no coal in open lake.
出处
《地球科学（中国地质大学学报）》
EI
CAS
CSCD
北大核心
1992年第2期113-120,T001,共9页
Earth Science-Journal of China University of Geosciences
关键词
三角洲-湖泊
沉积体系
聚煤
genetic stratigraphic unit, depositional system tract, delta-lacustrine depositional system,genetic facies,coal-forming,Yan' an Formation,Shenmu district,Ordos Basin.
