西南石油大学学报(自然科学版)

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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

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