鄂尔多斯盆地陇东地区延长组沉积相特征与层序地层分析  

Sedimentary Facies Characteristic and Sequence Stratigraphy Analysis of Yanchang Formation in Longdong Area,Ordos Basin

作　　者：李凤杰[1] 王多云[2] 张庆龙[1] 徐旭辉[3] 

机构地区：[1]南京大学,南京210093 [2]中国科学院地质与地球物理所兰州油气资源研究中心,兰州730000 [3]中国石油化工股份有限公司石油勘探开发研究院无锡石油地质研究所,江苏无锡214151

出　　处：《沉积学报》2006年第4期549-554,共6页Acta Sedimentologica Sinica

基　　金：中国科学院资源环境领域知识创新工程重要方向项目资助(编号:KZCX3-SW-128-04)

摘　　要：晚三叠世鄂尔多斯盆地是一个东缓西陡的不对称坳陷盆地。通过岩心、录井、测井等资料综合研究,识别出陇东地区延长组发育河流、三角洲、浊积扇和湖泊等4种沉积相类型,其中河流沉积和浊积扇发育在湖盆的西缘陡坡带,三角洲则在西缘和东部缘坡均有发育。根据层序地层学原理,将延长组划分出5个三级层序;延长组地层经历过5次大的湖泛,在层序演化上具有早期形成、中期鼎盛、晚期衰退的特点。利用恢复后的原始地层厚度,绘制的陇东地区延长组地层的F ischer图解,与本区5次显著的湖平面上升—下降旋回之间有很好的对应关系,这不仅证实了上述层序地层分析的正确性,同时揭示了F ischer图解在划分地层层序方面的潜在意义。At Late Triassic, Ordos Basin is an asymmetry depressed-type lacustrine basin with gentle slope in the east and steep slope in the west. By the research of core, logging profiles and seismic data, four types of sedimentary facies have been recognized. Among these sedimentary facies, river facies and turbidity fans are found on the steep slope in the west of the depression, while braid river deltas are the east of the depression. Based on the classic pattern quences have been identified in Yanchang formation, found on both the steep slope in the west and the gentle in of sequence stratigraphic framework, five three-order se- Longdong area. Five times of lake transgression can be distin- guished. The sequence evolution is that they formed in early time, reached the maximum in middle time and dechned in late time. Fischer＇s plots of Yanchang formation stratigraphy are scaled with retrieved stratigraphic thickness in Longdong area. There are well corresponding relations between the plots and five times of lake transgression. The classification of the sequence stratigraphy has been verified by using Fischer＇s plots, which may be a potential tool for sequence analysis.

关 键 词：层序地层 Fischer图解 延长组 鄂尔多斯盆地 

分 类 号：P539.2[天文地球—古生物学与地层学]