热带海洋学报 ›› 2016, Vol. 35 ›› Issue (4): 82-94.doi: 10.11978/2015124

• 海洋地质学 • 上一篇    下一篇

珠江口盆地白云凹陷裂陷期断裂结构与演化特点

张九园1, 2, 孙珍1, 郑金云3   

  1. 1. 中国科学院南海海洋研究所, 中国科学院边缘海地质重点实验室, 广东 广州 510301;
    2. 中国科学院大学, 北京 100049;
    3. 中海石油(中国)有限公司深圳分公司, 广东 广州 510240
  • 收稿日期:2015-10-10 出版日期:2016-07-29 发布日期:2016-08-04
  • 通讯作者: 孙珍。E-mail: zhensun@scsio.ac.cn
  • 作者简介:张九园(1990—), 男, 硕士研究生, 主要从事海洋地质沉积与构造方向研究。E-mail: zhangjiuyuan13@mails.ucas.ac.cn
  • 基金资助:
    国家重大油气专项(2011ZX05025-003-005); 国家自然科学基金委员会—广东省联合基金项目(U1301233)

The structure and evolving history of faults during rifting stage in Baiyun Sag, Pearl River Mouth Basin

ZHANG Jiuyuan1, 2, SUN Zhen1, ZHENG Jinyun3   

  1. 1. Key Laboratory of Marginal Sea Geology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China;
    2. University of Chinese Academy of Sciences, Beijing 100049, China;
    3. Shenzhen Branch, China National Offshore Oil Corporation Limited (CNOOC Ltd), Guangzhou 510240, China;
  • Received:2015-10-10 Online:2016-07-29 Published:2016-08-04
  • Contact: SUN Zhen. E-mail: zhensun@scsio.ac.cn
  • Supported by:
    Major National Oil and Gas Projects(2011ZX05025-003-005); The Joint Program of NSFC and Guangdong Province (U1301233)

摘要: 珠江口盆地白云凹陷地处南海北部深水陆坡区, 经历了古近纪两幕裂陷作用, 新近纪裂后沉降作用和中中新世以后的构造活化作用, 形成了多期继承性和新生性的断层系统。文章首先按剖面形态将裂陷期断层分为三类: 第一类为板式断层, 通常只断穿T60、T70和T80; 第二类为铲式断层, 断穿包括Tg在内的较多层位; 第三类为拆离断层, 断穿Tg层位, 垂向断距较铲式断层更大。然后, 利用高精度二维和三维地震剖面对白云凹陷南缘控凹断层的组合样式、活动性及演化史进行了分析, 结果表明: 在白云凹陷西南部发育雁列式断层组合, 雁列式断层组合中的铲式断层之间通过发育连接断层(板式断层), 调节变形或位移而保持区域伸展应变守恒; 白云凹陷中部大型断层存在平行发育关系, 4条铲式断层首先发育, 同步运动, 其中最靠近凹陷的一条活动速率最大, 板式断层在其断块之上后期发育; 而在白云凹陷东部的南侧边缘发育有低角度拆离断层, 在拆离断层上盘高角度旋转断块呈多米诺式排列, 下部整体滑移。在剖面活动性分析基础上文章探讨了其成因机制, 为白云凹陷油气勘探提供参考。

关键词: 白云凹陷, 断层结构, 控凹断层, 裂陷期, 拆离断层

Abstract: Located at the northern continental slope of the South China Sea, Baiyun Sag of the Pearl River Mouth Basin has gone through the evolution of two episodes of Paleogene rifting, Neogene post-rift subsiding, and tectonic reactivation after middle Miocene. Multi-phase fault systems were developed, and showed both inherited and newborn features. In this study, we divided faults during rifting stage into three kinds according to their scarp shapes. The first kind is planar fault, which usually cuts through only T60, T70 and/or T80, and has a straight fault plane. The second kind is listric fault, cutting through more horizons including Tg. The third kind is detachment fault, which cuts through Tg. Usually, it has a larger vertical displacement than the second kind. Then, we analyzed tectonic style, activity and evolving history of the sag-controlling faults combinations in the southern boundary of the Baiyun Sag with high-resolution 2D and 3D seismic profiles. The results are as follows: there developed large en echelon sag-controlling faults in the southwest of the sag, between them a connecting fault (planar fault) developed to keep regional stretch strain conservation by adjusting deformation and displacement. In the middle of Baiyun Sag’s southern part, four big listic faults are parallel to each other; they started activity at similar times, but the one near the sag center has the largest vertical offset; later the planar faults developed between them. In the northeast of Baiyun Sag, there developed low angle detachment faults in the sag boundary. High angle rotated fault blocks appeared as domino style and stopped their faulting by joining in the detachment fault. Based on the above profile analysis, this paper discussed the formation mechanism of the above-mentioned three kinds of sag-controlling fault systems, providing a reference to deep-sea oil-gas exploration. (in Chinese with English abstract)

Key words: Baiyun Sag, fault structure, sag-controlling fault, rifting stage, evolving history, detachment fault

中图分类号: 

  • P736