论文部分内容阅读
基于万安盆地地区的布格重力异常分布特征,在前人研究的基础上,通过滑动平均滤波法,将重力异常划分为区域场和局部场;利用水平总梯度法,强化深断裂的线性特征。结合区域地质、地震等相关资料,推断了盆地内断裂构造:一级断裂4条,二级断裂5条,三级断裂26条。将本次研究的断裂分布与前人研究进行对比得到新认识:位于万安盆地中部的F1-1断裂是形成于中生代的一条基底断裂,可能是南海西缘断裂带在万安盆地内的延伸段;万安盆地东缘断裂带不是一条断层,而是呈雁行排列的断层组,主断裂是一个左旋、右旋相互交替、多期活动的走滑断裂,对盆地形成东断西超断陷特征有强烈的控制作用。万安盆地处于南海地质构造最复杂的南部地区,经历了多次构造运动和多阶段演化,其构造演化受南海海底扩张和万安走滑断裂带的双重控制,断裂系统极其发育。
Based on the previous studies on the Bouguer gravity anomalies in the Wan’an basin, the gravity anomalies are divided into regional fields and local fields based on the sliding average filtering method. The horizontal total gradient method is used to enhance the linear features of the deep faults . Combined with regional geology, earthquake and other related data, it is inferred that the faults in the basin are composed of four primary faults, two secondary faults and 26 tertiary faults. Comparing the fracture distribution in this study with previous studies, we get a new understanding: the F1-1 fault located in the middle of Wan’an Basin is a basement fault formed in the Mesozoic, which may be an extension of the western margin of the South China Sea within the Wan’an Basin The east margin of Wan’an Basin is not a fault, but a fault group arranged in geese. The main fault is a strike-slip fault with alternating left and right hand rotation and multi-phase activities. Features have a strong control. The Wan’an Basin is in the southern part of the South China Sea with the most complicated geological structure and has undergone multiple tectonic movements and multi-stage evolutions. The tectonic evolution was controlled by both the South China Sea submarine expansion and the Wanan strike-slip fault zone, and the fault system developed extremely well.