利用地震前积反射特征确定古水流方向的沉积几何方法

A geometrical method of calculating paleocurrent direction using seismic progradation reflection characteristics

古水流条件分析是确定沉积盆地古水系、古物源及沉积体系展布,进行岩相古地理研究必不可少的内容。传统的古水流研究方法主要分为统计方法或百分比法、沉积几何学方法2类。根据地震剖面上前积反射的成因,利用交叉地震剖面上前积反射之间的几何关系,可以定量地确定古水流方向。这种方法适用于盆地勘探的不同阶段,与传统的沉积几何学方法比较,其不仅易于操作,而且便于更准确、定量地判定地质历史时期区域性的古水流主方向。盆地演化后期的构造改造会在不同程度上影响该方法的适用性,此时应与其他方法结合使用。

Analysis of paleocurrent conditions is the necessary part of the research on paleo-water and palaeo-source and depositional systems,and lithofacies paleo-geography in sedimentary basin.The traditional research methods can be divided into two types;statistics or percent methods and sedimentary geometry methods.According to the origin of progradation reflection in the seismic section,a geometrical method is introduced to calculate the paleocurrent direction quantitatively using the geometry relationships between progradation reflections in the cross sections.It fits to different stage of basin exploration.Compared with the traditional sedimentary geometry means,it has the advantages of convenient process,and also is easy to hold the regional paleocurrent directions of certain geologic period.At the later stage of basin e-volution,the availability of this means may be impacted by tectonic changes,thus it is necessary to be combined with other methods.