溱潼凹陷阜一段古地貌特征及其对沉积的控制作用

本文利用地震、测井及测试资料,应用回剥技术及计算剥蚀的趋势分析法,恢复了溱潼凹陷阜一段底界面同沉积期的古地貌。随后分析了阜一段沉积的古地貌特征及其对沉积的控制作用。研究表明：阜一段沉积前古地貌自东南向西北可分为泰州隆起、中央次深凹带和北部缓斜坡带三个沉积古地理单元。结合古地貌与沉积体系研究成果发现,古地貌对砂体展布具明显的控制作用：阜一段沉积时期古地貌呈现＂坡＂＂隆＂＂凹＂相间的格局,＂坡＂是沉积物的搬运通道,也是沉积物的堆积场所;＂隆＂是较大的物源区;＂凹＂是沉积物的堆积中心。在古构造及古地貌的双重作用下,构造高部位的物质或通过断阶带进入各次凹内沉积,或经由斜坡带水道搬运至凹陷中,最终形成了多个辫状三角洲体系沿盆地南北两侧构造带沉积的模式。

溱潼凹陷阜一段古地貌特征及其对沉积的控制作用

With the seismic data,logging data and testing data,by means of the back-striping technique and trend analysis method for erosion calculation,the syndepositional palaeogeomorphology of Ef1 has been rebuild in QinTong depression.Then Palaeogeomorphic Characteristics of Ef1 and Their Control on Sedimentation have been studied.This study indicates that from SE to NW the Palaeogeomorphology of Ef1 can be divided into three sedimentary paleo-geography units,namely TaiZhou uplift,central deep belt and north gentle slope belt.Combination of palaeogeomorphology and sedimentary system research shows that,palaeogeomorphology has conspicuous control on distribution of sand：palaeogeomorphology of Ef1 shows the structural pattern of＂slope＂,＂uplift＂and＂sag＂alternating with each other.The ＂slope＂ is the transportation pathway,and also the accumulation area;the ＂uplift＂ is the main source;the＂sag＂ is the accumulation centre of sediment.Since the dual control of structure and palaeogeomorphology,the detrital material of high structural location may enter into each sag though the step-fault zone and then deposits,or maybe debris is carried into sags by the channels on the slope,at last the depositional model is formed that a few braided deltas develop on the south and north structural belts of the basin.