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

Berndt, Christian, Jacobs, C. L., Evans, A. J., Gay, A., Elliot, G., Long, D. and Hitchen, K. (2012) Kilometre-scale polygonal seabed depressions in the Hatton Basin, NE Atlantic Ocean: Constraints on the origin of polygonal faulting Marine Geology, 332/334 . pp. 126-133. DOI 10.1016/j.margeo.2012.09.013.

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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 Previously unpublished high-resolution 2D seismic data from the same area show seismic disturbance zones similar to pipes observed under pockmarks elsewhere as well as faults that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.

Document Type: Article
Keywords: Polygonal faulting; Silicate diagenesis; Dewatering; Subsurface sediment deformation; Seismic data; Multibeam bathymetry data; FINE-GRAINED SEDIMENTS; MID-NORWEGIAN MARGIN; FLUID-FLOW; NORTH-SEA; COLUMNAR JOINTS; SHEAR FAILURE; CONGO BASIN; SYSTEMS; COMPACTION; MIOCENE
Research affiliation: OceanRep > GEOMAR > FB4 Dynamics of the Ocean Floor > FB4-GDY Marine Geodynamics
Refereed: Yes
DOI etc.: 10.1016/j.margeo.2012.09.013
ISSN: 0025-3227
Projects: HERMES
Date Deposited: 22 Dec 2011 15:17
Last Modified: 08 Aug 2017 11:32
URI: http://eprints.uni-kiel.de/id/eprint/13184

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