川东南涪陵地区长兴组层序地层及沉积相演化特征

在川东南涪陵地区长兴组沉积构造背景认识的基础上，以Vail 的经典层序地层学和Cross 的高 分辨率层序地层学理论方法为指导，采用野外露头、岩心及测井等多种分析手段，通过对层序界面、相序、 叠置结构、测井曲线等的综合识别分析，将川东南涪陵地区长兴组划分为2 个三级层序。进一步研究了 涪陵地区层序格架内长兴组沉积相垂向及平面上的分布情况，并在此基础上，从层序演化的角度研究了长兴组沉积时期礁滩体的分布情况。研究结果表明：长兴组下部三级层序海侵体系域（TST）时期涪陵地区礁滩体不发育，高水位体系域（HST）时期礁滩体较发育；上部三级层序沉积时期礁滩体均有发育，TST时期礁滩体的发育规模明显小于HST 时期的礁滩体规模。

Characteristics of sedimentary facies and sequence stratigraphy of Changxing Formation in Fuling area,southeastern Sichuan Basin

Based on the knowledge of sedimentary and tectonic settings of Changxing stage in Fuling area in south-eastern Sichuan Basin,under the guidance of the theory of classical sequence stratigraphy by Vail and high resolution sequence stratigraphy by Cross,by using outcrop,core and well logging analysis,the sequence boundary surface,facies sequence,stacking pattern and log curves are analyzed,and Changxing Formation in Fuling area is divided into two third-order sequences.The vertical and plane distribution of sedimentary facies of Changxing Formation in the sequence framework in Fuling area is studied,and the distribution of reef and shoal in Changxing stage is analyzed from the aspect of sequence evolution.The result shows that the reef and shoal bodies did not develop during the transgressive system tract phase in the third-order sequence of lower Changxing Formation in Fuling area,and then they developed fairly during the highstand system tract phase;reef and shoal bodies developed during the sedimentary stage of the third-order sequence of upper Changxing Formation,but their developing scales during transgressive system tract are signifi-cantly less than that during the highstand system tract.