石油与天然气地质 ›› 2019, Vol. 40 ›› Issue (1): 123-132.doi: 10.11743/ogg20190112

• 油气地质 • 上一篇    下一篇

中中新世以来南海南部前隆的迁移:来自北康盆地的证据

王龙樟1, 姚永坚2, 张莉2, 周江羽1, 徐行2, 肖娇静1, 沈奥1, 徐乔1   

  1. 1. 中国地质大学 构造与油气资源教育部重点实验室, 湖北 武汉 430074;
    2. 广州海洋地质调查局, 广东 广州 510760
  • 收稿日期:2018-09-13 修回日期:2018-10-08 出版日期:2019-02-28 发布日期:2018-12-08
  • 第一作者简介:王龙樟(1966-),男,博士、教授,石油地质与海洋地质学。E-mail:longz_wang@cug.edu.cn。
  • 基金项目:

    国家自然科学基金项目(41576068,91428205)。

Forebulge migration since the Mid-Miocene in the southern South China Sea: evidences from the Beikang Basin

Wang Longzhang1, Yao Yongjian2, Zhang Li2, Zhou Jiangyu1, XuXing2, Xiao Jiaojing1, Shen Ao1, Xu Qiao1   

  1. 1. Key Laboratory of Tectonics and Petroleum Resources of Ministry of Education, China University of Geosciences(Wuhan), Wuhan, Hubei 430074, China;
    2. Guangzhou Marine Geological Survey, Guangzhou, Guangdong 510760, China
  • Received:2018-09-13 Revised:2018-10-08 Online:2019-02-28 Published:2018-12-08

摘要:

利用二维地震资料探讨南海南部北康前隆的迁移现象及其对形成油气圈闭的影响。在南沙海域,早中新世不整合(EMU)是一个区域性不整合面,EMU之上的地层可以简单归结为披覆层系和水平层系。披覆层系直接覆盖在EMU上,具有连续薄层的平行地震反射特征,向南东方向加厚,属于悬浮沉积;而水平层系同期充填在低凹处,不断上超和覆盖早期的披覆层系,厚层状,呈不连续或弱反射特征,属于浊积物与悬浮物的混合沉积。通过上超反射终止的迁移和披覆层系的加厚两个特征判断,中中新世以来北康前隆在向上隆升的同时不断向南东方向迁移,反映了南沙海域减薄的陆壳有一个强烈挠曲和均衡反弹过程。前隆的迁移留下了一系列的古潜山,披覆层系和水平层系是很好的盖层,有利于圈闭的形成。

关键词: 前隆迁移, 披覆层系, 水平层系, 古潜山圈闭, 晚新生代, 前陆盆地, 北康盆地

Abstract:

The 2D seismic data were used to discuss the migration of the Beikang forebulge in the southern South China Sea and its impact on trap formation.The strata overlying the Early Miocene Unconformity(EMU),a regional unconformity,could be simply categorized as draping and horizontal layer series in the Nansha sea area.The draping layer series overlie the EMU directly,show parallel seismic reflection characters of continuous thin layers and thicken southeastward,suggesting suspended sediments.While the horizontal layer series were deposited synchronously in structural lows and continuously onlapped and overlay the draping strata formed early.They are mixed thick sedimentary layers of turbidites and suspended sediments featuring discontinuous or weak seismic reflection.Judged by the migration of onlap reflection termination and thickening of the draping strata,the forebulge has migrated southeastward during its uplifting since the Mid-Miocene,indicating a process of intense flexure and equilibrium rebound occurring at the thinned continental crust in the Nansha sea area.The forebulge migration has caused the formation of a host of buried hills,with the draping and horizontal series of strata serving as favorable seals,which in turn will be conducive to the formation of traps.

Key words: forebulge migration, draping layer series, horizontal layer series, buried-hill trap, Late Cenozoic, foreland basin, Beikang Basin

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