Knickpoint migration in submarine channels in response to fold growth, western Niger Delta

Päivi Heiniö*, Richard J. Davies

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Several knickpoints have been identified along the present-day thalweg of a sinuous submarine channel-levee system (CLS) on the slope of the western Niger Delta using 3D seismic data. The knickpoints form as a result of gradient changes caused by the uplift of a thrust and fold belt orthogonal to the CLS. The channel gradient is lower locally upstream of folds causing turbidity currents within the channel to decelerate and deposit the coarsest sediment load. The basinward dipping fold limb causes local steepening of the gradient, which leads to increased flow velocity and turbulence within the turbidity currents. This enhances erosion at the base of the channel and leads to the formation of a knickpoint. If preserved, e.g., as a result of channel avulsion or abandonment, the deposits upstream of the knickpoints could constitute an important hydrocarbon reservoir element. They can, however, also be partially eroded by headward-migrating knickpoints, as the channel strives to regain its equilibrium profile, leaving remnant sand pockets preserved on channel margins. Although knickpoints are difficult to recognise from subsurface seismic or outcrop data, it is anticipated that they can form at any stage of the evolution of a channel-levee system and may be particularly important in controlling 3D channel architecture where channels intersect dynamically changing seabed bathymetry.

Original languageEnglish
Pages (from-to)434-449
Number of pages16
JournalMarine and Petroleum Geology
Volume24
Issue number6-9
DOIs
Publication statusPublished - Jun 2007
Externally publishedYes

ASJC Scopus subject areas

  • Oceanography
  • Geophysics
  • Geology
  • Economic Geology
  • Stratigraphy

Keywords

  • Knickpoints
  • Niger Delta
  • Submarine channels

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