苏北盆地高邮凹陷第三系—上白垩统层序地层格架特征

The Character of Sequence Framework of Tertiary and Upper Cretaceous in Gaoyou Sag, Subei Basin

依据地震、钻测井、岩芯、古生物等资料中的层序地层特征 ,可将高邮凹陷厚达 70 0 0m的第三系—上白垩统泰州组划分为 2个一级层序 ,4个二级层序 ,11个三级层序。进而依据最大湖泛面和断裂坡折带 (首次湖泛面 )对三级层序进行了体系域划分。在 11个三级层序中识别出低位、湖侵和高位体系域的不同组合。由于汉留断层在高邮凹陷东西向上发育的程度不同 ,造成凹陷西部为双断断陷式盆地结构 ,东部为单断断箕式盆地结构 ,据此建立了高邮凹陷西部具断裂坡折带和东部无明显坡折带的层序地层样式。最后分析了层序发育的主控因素 ,认为构造和气候是高邮凹陷层序发育的主控因素。

Based on the analysis of seismic data, borehole and well-logging,core and paleontology of Tertiary and upper Cretaceous with thickness of more than 7000m in Gaoyou Sag, Subei Basin, two first-level sequences, four second-level sequences and 11 third-sequences have been identified. System tracts were also identified within each sequence based on the maximum flooding surface and fault-break(first flooding surface). Each of the 11 sequences consists of either complete lowstand, transgressive and highstand system tracts or one or two of them. Due to the different activity of Hanliu fault in the east and west part of Gaoyou sag, the west part is characterized by bi-fault subsiding basin, and the east part single-fault basin. Based on structural analysis, sequence pattern in Gaoyou sag may be described as the west part with fault-break and east without break. The main controlling factors of sequence stratigraphy was analyzed and were believed to be tectonics and climate.