西湖凹陷渐新统花港组下段沉积相特征及模式

东海陆架盆地西湖凹陷花港组沉积相一直存在争议,文章以岩心观察为基础,通过区域地质、古生物、测井和地震资料综合分析,对西湖凹陷花港组下段沉积相类型、特征和分布规律进行了详细研究。研究认为,花港组下段发育曲流河扇、辫状河扇、曲流河三角洲、辫状河三角洲等4种相类型,凹陷西北部发育曲流河扇沉积,凹陷东北部发育辫状河扇沉积,中南部广泛发育曲流河三角洲和辫状河三角洲沉积。在沉积相平面分布特征的基础上结合区域构造特征,建立了西湖凹陷渐新统花港组下段沉积相模式。

Sedimentary facies characteristics and its mode of lower member of Oligocene Huagang formation in Xihu sag

The sedimentary facies of Xihu sag in Donghai shelf basin has been controversial.Based on core observation,combined with regional geology,paleontology,logging and seismic data,a comprehensive analysis of lower member of Oligocene Huagang formation in Xihu sag,such as sedimentary facies types,characteristics and distribution laws have been discussed in detail.The studies indicate lower member ofHuagang formation mainly developed four types,namely meandering river fan,braided river fan,meandering river delta and braided river delta.In northwestern sag,meandering river fan developed.In northeastern sag,braided river sedimentary developed.In south-central sag,meandering river delta and braided river delta deposits widely developed.On the basis of planar distribution of sedimentary facies characteristics and in combination with regional structure features,the related sedimentary facies models have been established.