西南石油大学学报(自然科学版)

• 地质勘探 • 上一篇    下一篇

白云凹陷水道几何形态研究

乔博1 *,张昌民1,李少华1,杜家元2,李向阳1,3   

  1. 1. 长江大学油气资源与勘探技术教育部重点实验室,湖北荆州434023
    2. 中国海洋石油总公司深圳分公司研究院,广东广州510083
    3. 河南省核工业地质局,河南信阳464000
  • 出版日期:2015-04-01 发布日期:2015-04-01
  • 通讯作者: 乔博,E-mail:qb123124@126.com
  • 基金资助:

    国家“十二五”重大专项(2011ZX05023 – 002 – 007);国家自然科学基金(41302096)。

Study of the Configuration of Two Types of Submarine Channels
in the Baiyun Sag,Pearl River Mouth Basin

Qiao Bo1*, Zhang Changmin1, Li Shaohua1, Du Jiayuan2, Li Xiangyang1,3   

  1. 1. MOE Key Laboratory of Exploration Technologies for Oil and Gas Resources,Yangtze University,Jingzhou,Hubei 434023,China
    2. Research Institution,Shenzhen Branch,CNOOC,Guangzhou,Guangdong 510083,China
    3. Henan Province Nuclear Geology Bureau,Xinyang,Henan 464000,China
  • Online:2015-04-01 Published:2015-04-01

摘要:

以珠江口盆地白云凹陷中的水道为例,对水道的几何形态展开研究,通过均方根振幅属性图确定水道的整体
形态,截取若干横截面刻画水道的内部结构,并测量水道的深度和宽度,计算宽深比。研究发现,在该地区发育有两种
几何形态的水道,21.0∼18.5 Ma 时期水道变宽变浅和10.5∼8.5 Ma 时期水道变窄变深。水道的形态首先受到古地貌的
控制,21.0∼18.5 Ma 时期和10.5∼8.5 Ma 时期不同的地貌环境对两个时期水道的发育有重要的影响。此外,沉积流体
的侵蚀能力也影响了水道的形态。在21.0 Ma 时海平面上升,并且远离沉积物源会导致水道中的沉积物供给降低,流
体侵蚀能力较小,故水道变宽变浅。在10.5 Ma 时由于东沙隆起抬升的影响,并靠近物源使得水道中沉积物更多地以
重力流形式向下搬运沉积,侵蚀能力较强,故水道变窄变深。水道几何形态研究对研究水道的整体演化过程有重要意
义,也有助于了解该地区的沉积条件。

关键词: 白云凹陷, 水道, 几何形态, 古地貌, 海平面变化

Abstract:

Taking the submarine channels in the Baiyun Sag as examples,we carried out the study of the geometry of the
submarine channels. We defined the shape of the submarine channels through RMS attribution map,described the internal
structure,measured the depth and width of the channels and calculated the width/depth ratio. Through these studies,we found
there are two types of submarine channels in the Baiyun Sag,Pearl River Mouth Basin. One type is wider and shallower in
21.0∼18.5 Ma,the other type narrower and deeper in 10.5∼8.5 Ma. The geometry of submarine channels are largely controlled
by the topography;different topographies in these two phases play an important role in the submarine channel development.
Besides,the erosion of the flow in the channels could influence the geometry of submarine channels. In 21.0 Ma,the sea-level
rises and the sediment supply decreases as the channel is far from the paleo-Pearl River Delta,so that the channel becomes
wider and shallower. In 10.5 Ma,as the Dongsha Uplift rose and the channel is close to the paleo-Pearl River Delta,so that the
sediment is transported in the form of the gravity flow,which leads to high erosion ability. Ultimately the submarine channel
becomes narrower and deeper. The research of the geometry of submarine channels is important in understanding the evolution
of the channels and helpful to explore the sedimentary condition of this area.

Key words: Baiyun Sag, submarine channel, geometry, topography, sea-level change