石油与天然气地质 ›› 2023, Vol. 44 ›› Issue (3): 753-763.doi: 10.11743/ogg20230317

• 油气地质 • 上一篇    下一篇

东海陆架盆地西湖凹陷天台斜坡构造变换带发育特征及形成机理

余浪1,2(), 余一欣1,2(), 蒋一鸣3, 邹玮3, 陈石1,2, 唐贤君3, 梁鑫鑫1,2, 何新建3, 陈冬霞1,2   

  1. 1.中国石油大学(北京) 油气资源与探测国家重点实验室,北京 102249
    2.中国石油大学(北京) 地球科学学院,北京 102249
    3.中海石油(中国)有限公司 上海分公司,上海 200030
  • 收稿日期:2022-11-07 修回日期:2023-03-07 出版日期:2023-06-01 发布日期:2023-06-05
  • 通讯作者: 余一欣 E-mail:yulang2634@163.com;yuxin0707@163.com
  • 第一作者简介:余浪(1997—),男,博士研究生,油区构造解析。E?mail: yulang2634@163.com
  • 基金项目:
    国家自然科学基金项目(42072149);中海石油(中国)有限公司科研项目(CNOOC-KJ 135 ZDXM 39 SH01)

Characteristics and forming mechanisms of transform zone in the Tiantai slope, Xihu Sag, East China Sea Shelf Basin

Lang YU1,2(), Yixin YU1,2(), Yiming JIANG3, Wei ZOU3, Shi Chen1,2, Xianjun TANG3, Xinxin LIANG1,2, Xinjian HE3, Dongxia CHEN1,2   

  1. 1.State Key Laboratory of Petroleum Resources and Prospecting,China University of Petroleum (Beijing),Beijing 102249,China
    2.College of Geosciences,China University of Petroleum (Beijing),Beijing 102249,China
    3.Shanghai Branch,CNOOC,Shanghai 200030,China
  • Received:2022-11-07 Revised:2023-03-07 Online:2023-06-01 Published:2023-06-05
  • Contact: Yixin YU E-mail:yulang2634@163.com;yuxin0707@163.com

摘要:

东海陆架盆地西湖凹陷天台斜坡构造位置特殊,深层NW向断裂带从斜坡区通过,并对斜坡南、北部新生界的构造特征起到了明显的调节和变换作用。通过三维地震资料精细解释和平衡剖面复原,建立了天台斜坡深层NW向断裂和浅层断裂的发育模式,厘定了NW向变换带的构造属性,同时结合区域地质背景,探讨了构造变换带的演化过程和形成机理。结果表明:天台斜坡中生界发育包括天台西断裂和孤山断裂在内的NW向伸展滑脱断层,并对斜坡南、北部新生界地质结构、断裂发育和伸展强度等起到了明显的调节和变换作用。天台斜坡北部和南部分别表现为缓坡和陡坡结构特征,北部断裂密集发育,而且孤山断裂上盘发育弧形断裂,北部伸展强度也要明显大于南部。发育于天台西断裂和孤山断裂之间的NW向构造变换带明显不同于伸展背景下的变换构造,属于离散构造变换带。受秦岭-大别造山后碰撞伸展作用与欧亚板块和太平洋板块的碰撞、俯冲过程影响,天台斜坡构造变换带主要经历了晚侏罗世—早白垩世初期变换带孕育期、早白垩世中期—早始新世变换带雏形期、中晚始新世—渐新世早期变换带成熟期和渐新世晚期—现今变换带静止期4个演化阶段。

关键词: 弧形断裂, NW向断裂, 构造变换带, 天台斜坡, 西湖凹陷, 东海陆架盆地

Abstract:

The Tiantai slope in the Xihu Sag, East China Sea Shelf Basin, has a special tectonic background with a deep NW-trending fault zone cutting through and adjusting/transforming the tectonic features of the Cenozoic in the southern and northern parts of the slope. Based on the detailed interpretation of 3D seismic data and restored balanced cross sections, this study establishes models for the development of deep and shallow faults, determines the tectonic attribute of the NW-trending transform zone and discusses the evolution history and genetic mechanisms of the transform zone against regional geological settings. The results show that the NW-trending extensional detachment faults, including the Tiantaixi fault and the Gushan fault, were developed in the Mesozoic of the Tiantai slope, and have played an accommodating and transforming role in shaping the geological framework and controlling fault development and extension intensity of the Cenozoic, resulting in a gentle and a steep slope respectively on the south and more stretched north parts of the slope. The faults of the Cenozoic in the northern slope obviously outnumber those in the southern slope. Arc fault systems are found to be developed in the hanging wall of the Gushan fault. The NW-trending tectonic transform zone bounded by the Tiantaixi fault and the Gushan fault differs greatly from that formed in the extensional setting, indicating a discrete type of tectonic transform zone. Influenced by the post-orogenic collision and extension between the Qinling and Dabie orogenic belts, and the collision and subduction of the Eurasian and Pacific plates, the transform zone in the Tiantai slope has experienced four evolutionary stages, including the gestation period from the Late Jurassic to the Early Cretaceous, the embryonic period from the middle Early Cretaceous to the Early Eocene, the maturation period from the middle Late Eocene to the Early Oligocene, and the quiescence stage from the Late Oligocene to present.

Key words: arc fault, NW-trending fault, tectonic transform zone, Tiantai slope, Xihu Sag, East China Sea Shelf Basin

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