珠江口盆地西部文昌A凹陷断裂特征与成因探讨  

Discussion on fault characteristics and genesis of Wenchang A Sag in the west of the Pearl River Mouth Basin

作　　者：张豪 栾锡武[2,3] 冉伟民 王阔 魏新元 石艳锋 Mohammad Saiful Islam[4,5] 王嘉 ZHANG Hao;LUAN Xiwu;RAN Weimin;WANG Kuo;WEI Xinyuan;SHI Yanfeng;Mohammad Saiful Islam;WANG Jia(China University of Petroleum,Qingdao 266580,China;Qingdao Institute of Marine Geology,China Geological Survey,Qingdao 266071,China;Laboratory for Marine Mineral Resources,Pilot National Laboratory for Marine Science and Technology,Qingdao 266237,China;Shandong University of Science and Technology,Qingdao 266590,China;University of Dhaka,Dhaka 1000,Bangladesh;Ocean University of China,Qingdao 266100,china)

机构地区：[1]中国石油大学(华东),青岛266580 [2]中国地质调查局青岛海洋地质研究所,青岛266071 [3]青岛海洋科学与技术试点国家实验室海洋矿产资源评价与探测技术功能实验室,青岛266237 [4]山东科技大学,青岛266590 [5]达卡大学,孟加拉达卡1000 [6]中国海洋大学,青岛266100

出　　处：《海洋地质与第四纪地质》2020年第4期96-106,共11页Marine Geology & Quaternary Geology

基　　金：中国东盟海上合作基金项目(12120100500017001);青岛海洋科学与技术试点国家实验室基金项目(QNLM201708);自然资源部公益性行业科研专项基金“海底冷泉拖曳式快速成像系统研制及应用”(201511037);海洋矿产资源评价与探测技术功能实验室开放基金“开平凹陷地区地质与矿产资源勘探”(MMRKF201804);鳌山科技创新项目(2016ASKJ11,2016ASKJ13,2017ASKJ02)。

摘　　要：在前人勘探解释的基础上,通过三维高分辨率地震资料,应用相干属性分析等技术对区域断裂进行精细化解释.研究表明盆地内发育着典型的犁式、花状构造、旋转正断层等伸展构造样式,在珠三南断裂影响下,南部边界断裂以阶梯状排列形成断阶构造.始新世—中中新世,断裂走向在持续右旋张扭应力场下以NE→EW→NWW顺时针方向旋转,张裂强度逐渐减弱.晚始新世—早渐新世,盆地在太平洋板块俯冲后退、印亚板块碰撞、古南海向南俯冲下发育EW向断裂,晚渐新世在南海扩张事件影响下前期右旋应力场得到加强,形成大量近EW向断裂,中新世后演化为NWW向断裂.文昌A凹陷断裂构造的演化、成因机制与南海北部陆缘应力场变化一致.该研究有利于进一步了解南海北部陆缘含油气盆地的构造特征和演化规律,提高油气勘探开发的效率.On the basis of previous researches,fine interpretation is made for the fault systems of the Wenchang A Sag with the data of 3D highresolution seismic survey,coherence attribute analysis and other techniques.The results show that the basin is characterized by typical extensional structures,such as plow-like structures,flower-like structures and rotating normal faults.Affected by the Zhu-3 south fault,the southern boundary of the fault system shows a step-like pattern.During the period from Late Eocene to Early Oligocene,EW faults were developed under the subduction and retreat of the Pacific Plate,the collision with the Indo-subduction plate,and the southward subduction of the ancient South China Sea.During the period of Late Oligocene,however,under the influence of the South China Sea expansion event,the early dextral stress field was strengthened,while formed the nearly EW fault,and then evolved to those in NWW trending.From Late Eocene to middle Miocene,the fault trend rotates clockwise in the direction from NE to EW to NWW under the action of continuous right-hand tensional stress field.The tensile strength gradually weakened later on.Data suggests that the evolution and genetic mechanism of the faults in the Wenchang A Sag are consistent with the variation in stress field on the Northern Continental Margin of the South China Sea.This study is conducive to further understanding the structural characteristics and evolution of the oil-bearing basins on the northern margin of the South China Sea and improving the efficiency of oil and gas exploration and development.

关 键 词：断裂体系 断层活动性 应力场变化 珠江口盆地 文昌A凹陷 

分 类 号：P736.1[天文地球—海洋地质]