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Kilometre-scale polygonal seabed depressions in the Hatton Basin, NE Atlantic Ocean: Constraints on the origin of polygonal faulting

Kilometre-scale polygonal seabed depressions in the Hatton Basin, NE Atlantic Ocean: Constraints on the origin of polygonal faulting
Kilometre-scale polygonal seabed depressions in the Hatton Basin, NE Atlantic Ocean: Constraints on the origin of polygonal faulting
Polygonal faulting is a widespread phenomenon in sedimentary basins worldwide. It changes basin-scale fluid flow patterns and alters the physical properties of the sediments making it important for hydrocarbon exploration and geohazard analysis. It is generally accepted that polygonal fault patterns derive from dewatering and compaction of the host sediments, but there is debate regarding the processes that control polygonal faulting. New multibeam-bathymetry data from the Hatton Basin, NE Atlantic, show up to 10 m deep and 200–600 m wide troughs at the seabed. They connect to each other forming polygons that are several hundred metres across, i.e. of similar size as buried polygonal fault systems observed in 3D seismic data. The troughs are symmetrical and resemble elongated pockmarks. Previously unpublished high-resolution 2D seismic data from the same area show seismic disturbance zones similar to pipes observed under pockmarks elsewhere as well as faults that have all the characteristics of polygonal fault systems. The observation of the wide disturbance zones is enigmatic, as they appear to follow the polygonal seafloor pattern. The observed extent of the polygonal sediment contraction system is substantial covering almost 37,000 km2. We calculate that some 2600 km3 of possibly carbon-bearing fluids have been expelled from this system and we expect that this will affect the benthic ecosystems, although so far there is only limited evidence for chemosynthetic habitats.
Polygonal faulting, Silicate diagenesis, Dewatering, Subsurface sediment deformation, Seismic data, Multibeam bathymetry data
0025-3227
126-133
Berndt, Christian
d6db3f62-9891-4e8a-9210-b3aa6a8a4c22
Jacobs, Colin
1624f91c-deee-496d-bd5b-7cd1e88f652b
Evans, Alan
4492478c-e994-42bf-b943-97844eda8230
Gay, Aurélien
326b1ea4-ba4e-4806-bdc6-9425ce620ab7
Elliott, Gavin
c80ea2b2-d6eb-4a33-8ffc-b1ef30ecbc81
Long, David
40d62863-d9b2-4bcb-8e90-0152c22c636a
Hitchen, Kenneth
bef9c3a1-08c3-48c9-8fbe-78f0a189f104
Berndt, Christian
d6db3f62-9891-4e8a-9210-b3aa6a8a4c22
Jacobs, Colin
1624f91c-deee-496d-bd5b-7cd1e88f652b
Evans, Alan
4492478c-e994-42bf-b943-97844eda8230
Gay, Aurélien
326b1ea4-ba4e-4806-bdc6-9425ce620ab7
Elliott, Gavin
c80ea2b2-d6eb-4a33-8ffc-b1ef30ecbc81
Long, David
40d62863-d9b2-4bcb-8e90-0152c22c636a
Hitchen, Kenneth
bef9c3a1-08c3-48c9-8fbe-78f0a189f104

Berndt, Christian, Jacobs, Colin, Evans, Alan, Gay, Aurélien, Elliott, Gavin, Long, David and Hitchen, Kenneth (2012) Kilometre-scale polygonal seabed depressions in the Hatton Basin, NE Atlantic Ocean: Constraints on the origin of polygonal faulting. Marine Geology, 332-334, 126-133. (doi:10.1016/j.margeo.2012.09.013).

Record type: Article

Abstract

Polygonal faulting is a widespread phenomenon in sedimentary basins worldwide. It changes basin-scale fluid flow patterns and alters the physical properties of the sediments making it important for hydrocarbon exploration and geohazard analysis. It is generally accepted that polygonal fault patterns derive from dewatering and compaction of the host sediments, but there is debate regarding the processes that control polygonal faulting. New multibeam-bathymetry data from the Hatton Basin, NE Atlantic, show up to 10 m deep and 200–600 m wide troughs at the seabed. They connect to each other forming polygons that are several hundred metres across, i.e. of similar size as buried polygonal fault systems observed in 3D seismic data. The troughs are symmetrical and resemble elongated pockmarks. Previously unpublished high-resolution 2D seismic data from the same area show seismic disturbance zones similar to pipes observed under pockmarks elsewhere as well as faults that have all the characteristics of polygonal fault systems. The observation of the wide disturbance zones is enigmatic, as they appear to follow the polygonal seafloor pattern. The observed extent of the polygonal sediment contraction system is substantial covering almost 37,000 km2. We calculate that some 2600 km3 of possibly carbon-bearing fluids have been expelled from this system and we expect that this will affect the benthic ecosystems, although so far there is only limited evidence for chemosynthetic habitats.

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More information

Published date: 2012
Keywords: Polygonal faulting, Silicate diagenesis, Dewatering, Subsurface sediment deformation, Seismic data, Multibeam bathymetry data
Organisations: Marine Geoscience

Identifiers

Local EPrints ID: 346587
URI: https://eprints.soton.ac.uk/id/eprint/346587
ISSN: 0025-3227
PURE UUID: 35905e9f-fc75-42c1-bcba-6810ceb983f6

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Date deposited: 02 Jan 2013 17:16
Last modified: 16 Jul 2019 21:47

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Contributors

Author: Christian Berndt
Author: Colin Jacobs
Author: Alan Evans
Author: Aurélien Gay
Author: Gavin Elliott
Author: David Long
Author: Kenneth Hitchen

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