Brooks, HL, Hodgson, DM orcid.org/0000-0003-3711-635X, Brunt, RL et al. (2 more authors) (2018) Exhumed lateral margins and increasing flow confinement of a submarine landslide complex. Sedimentology, 65 (4). pp. 1067-1096. ISSN 0037-0746
Abstract
Submarine landslides, including the basal shear surfaces along which they fail, and their subsequent infill, are commonly observed in modern seabed and seismic reflection data sets; their resultant relief impacts sediment routing and storage patterns on continental margins. Here, three stacked submarine landslides are documented from the Permian Ecca Group, Laingsburg depocentre, Karoo Basin, South Africa, including two superimposed lateral margins. The stratigraphic framework includes measured sections and correlated surfaces along a 3 km long, 150 m high outcrop. Two stacked 2·0 to 4·5 km wide and 90 m and 60 m deep erosion surfaces are recognized, with lateral gradients of 8° and 4°, respectively. The aim of this study was to understand the evolution of a submarine landslide complex, including: evolution of basal shear surfaces/zones; variation of infill confinement; and location of the submarine landslides in the context of basin‐scale sedimentation and degradation rates. Three stages of formation are identified: (i) failure of submarine landslide 1, with deposition of unconfined remobilized deposits; (ii) failure of submarine landslide 2, forming basal shear surface/zone 1, with infill of remobilized deposits and weakly confined turbidites; and (iii) failure of submarine landslide 3, forming basal shear surface/zone 2, with infill of remobilized deposits and confined turbidites, transitioning stratigraphically to unconfined deposits. The expression of basal shear varies laterally, from metres thick zones in silt‐rich strata to sharp stepped surfaces in sand‐rich strata. Faulting and rotation of overlying bedding suggest that the shear surfaces/zones were dynamic. Stacking of landslides resulted from multi‐phase slope failure, increasing down‐dip topography and confinement of infilling deposits. The failure slope was probably a low supply tilted basin margin evidenced by megaclast entrainment from underlying basin‐floor successions and the lack of channel systems. This study develops a generic model of landslide infill, as a function of sedimentation and degradation rates, which can be applied globally.
Metadata
Item Type: | Article |
---|---|
Authors/Creators: |
|
Copyright, Publisher and Additional Information: | © 2017 The Authors. Sedimentology © 2017 International Association of Sedimentologists. This is the peer reviewed version of the following article: Brooks, H. L., Hodgson, D. M., Brunt, R. L., Peakall, J. , Flint, S. S. and Trofimovs, J. (2018), Exhumed lateral margins and increasing flow confinement of a submarine landslide complex. Sedimentology, 65: 1067-1096. doi:10.1111/sed.12415, which has been published in final form at https://doi.org/10.1111/sed.12415. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | Basal shear surface; basal shear zone; lateral margin; slope failure; submarine landslide |
Dates: |
|
Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Environment (Leeds) > School of Earth and Environment (Leeds) > Institute for Applied Geosciences (IAG) (Leeds) |
Funding Information: | Funder Grant number Conoco Phillips Not Known Statoil SLOPE4 Total E&P UK Ltd SLOPE4 BHP Petroleum (Americas) Inc SLOPE4 BP Egypt Company SLOPE4 Maersk Olie og Gas A/S MAERSK VNG Norge AS SLOPE4 |
Depositing User: | Symplectic Publications |
Date Deposited: | 21 Sep 2017 09:29 |
Last Modified: | 21 Sep 2018 00:38 |
Status: | Published |
Publisher: | Wiley |
Identification Number: | 10.1111/sed.12415 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:121509 |