Deep-water sedimentation processes on a glaciated margin: the Foula Wedge trough mouth fan, West of Shetland.

Simona Caruso; Vittorio Maselli; Brice Rea; Matteo Spagnolo

doi:10.1016/j.margeo.2022.106769

Deep-water sedimentation processes on a glaciated margin: the Foula Wedge trough mouth fan, West of Shetland.

Simona Caruso^* (Corresponding Author), Vittorio Maselli, Brice Rea, Matteo Spagnolo

^*Corresponding author for this work

Dalhousie University

Research output: Contribution to journal › Article › peer-review

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Abstract

Trough Mouth Fans (TMF) are sedimentary depocenters located at glaciated continental margins and consist predominantly of glacigenic debris flow deposits. The Foula wedge is a Pleistocene TMF accumulated offshore West of Shetland over the Northeast Atlantic margin. This study presents an analysis of a 3D seismic reflection dataset imaging the distal Foula wedge basin fan deposits between 1010 and 1100 m water depth, directly downslope from a gully system which was active untill the end of the last deglaciation. Results reveal, in unprecedented detail, the basal surface of this fan system and its internal complex architecture. Features typical of both debris flow deposits and turbidites are identified, including a basin channel network with linear and diverging erosional features forming distinctive terminal lobes, stacked and backstepping. The study links the seafloor morphology of the basin fan with its subsurface geomorphology, showing connection with the downslope gully system to the east. It presents evidence for a complex distal depositional system on glaciated margins, characterised by heterogeneous sediment delivery processes and deposits. A conceptual evolution model is proposed, with a glacigenic debris flow-dominated TMF at the LGM, subsequently influenced by
meltwater discharges, with deposition occurring as a function of the shelf margin andvised slope paleo-morphology, slope substrate composition, interaction of downslope and along slope processes and ice-margin dynamics.

Original language	English
Article number	106769
Number of pages	25
Journal	Marine Geology
Volume	446
Early online date	15 Mar 2022
DOIs	https://doi.org/10.1016/j.margeo.2022.106769
Publication status	Published - 1 Apr 2022

Bibliographical note

Acknowledgments
We acknowledge and thank Siccar Point Energy for permission to use and present their 3D seismic reflection and well data. We are thankful to Vela Software International, IHS, and Schlumberger for granting access to their interpretation and visualisation software Petrosys PRO, Kingdom Suite, and Petrel, respectively. Thanks to Ben Kneller for his interest and insightful discussion on turbidite versus debris flow processes. The authors would like to thank the Editor Michele Rebesco and two anonymous reviewers who helped
improve the quality of the manuscript. S. Caruso has been supported by the University of Aberdeen Elphinstone PhD scholarship. V. Maselli acknowledges support from the Natural Sciences and Engineering Research Council of Canada Discovery Grant (RGPIN-2020–04461).

Data Availability Statement

The 3D seismic reflection data used in this study have been provided by Siccar Point Energy under a non-disclosure agreement between Siccar Point Energy and the University of Aberdeen. This dataset is not publicly accessible, so please contact the Authors to obtain information on how to access the data. Seafloor photograph presented in Fig. 4B is courtesy of Siccar Point Energy as part of the survey data package provided by Fugro (2017). AFEN (2000) bathymetry data for this study were obtained via Fugro GB (North) Marine Limited in 2019. EMODnet Bathymetry is Open Source at: http://www.emodnet-bathymetry.eu. Boreholes and sub-bottom profiles from the British Geological Survey (BGS) are available under Open Government Licence at GeoIndex Offshore | BGS, Interactive map at http://mapapps2.bgs.ac.uk/geoindex_offshore/home.html?_ga=2.227456346.671481726.1639228033-183223392.1589786690#.

Glacial landforms used in Fig. 1, Fig. 2 are Open Source at BRITICE Glacial Map v2.0 Interactive Map at https://shefuni.maps.arcgis.com/apps/webappviewer/index.html?id=fd78b03a74bb477c906c5d4e0ba9abaf.

Regional topography presented in Fig. 1 is provided by EMODnet Bathymetry Consortium 2020. Bathymetric data presented in Figs. 2A, Fig. 12, Fig. 13, Fig. 14 are derived from a combination of multiple sources, which have been geo-referenced and composed in PetrosysPRO: 1) the seafloor horizon extracted from the 3D seismic reflection data provided by Siccar Point Energy, 2) AFEN (2000) dataset, 3) EMODnet (2020) dataset, 4) Bathymetry map images extracted from Long et al. (2004) and Stewart and Long (2016).

The geoprofile presented in Fig. 2B is extrapolated and exported from bathymetry data using PetrosysPRO and subsurface interpretation is after Stoker (1995), Davison (2004), Smallwood (200), and Stoker and Varming (2011).

For all data listed above, excluding the 3D seismic dataset, refer to Table 1 for further details on data type and source links.

Keywords

Deep-water sedimentation processes
Glacigenic debris flows
Basin fan deposits
Trough mouth fan
Subglacial meltwater
West of Shetland
Seismic geomorphology

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The spectacular overburden of the Cambo field
Simona Caruso, Brice Rea & Matteo Spagnolo
31/03/22
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title = "Deep-water sedimentation processes on a glaciated margin: the Foula Wedge trough mouth fan, West of Shetland.",

abstract = "Trough Mouth Fans (TMF) are sedimentary depocenters located at glaciated continental margins and consist predominantly of glacigenic debris flow deposits. The Foula wedge is a Pleistocene TMF accumulated offshore West of Shetland over the Northeast Atlantic margin. This study presents an analysis of a 3D seismic reflection dataset imaging the distal Foula wedge basin fan deposits between 1010 and 1100 m water depth, directly downslope from a gully system which was active untill the end of the last deglaciation. Results reveal, in unprecedented detail, the basal surface of this fan system and its internal complex architecture. Features typical of both debris flow deposits and turbidites are identified, including a basin channel network with linear and diverging erosional features forming distinctive terminal lobes, stacked and backstepping. The study links the seafloor morphology of the basin fan with its subsurface geomorphology, showing connection with the downslope gully system to the east. It presents evidence for a complex distal depositional system on glaciated margins, characterised by heterogeneous sediment delivery processes and deposits. A conceptual evolution model is proposed, with a glacigenic debris flow-dominated TMF at the LGM, subsequently influenced bymeltwater discharges, with deposition occurring as a function of the shelf margin andvised slope paleo-morphology, slope substrate composition, interaction of downslope and along slope processes and ice-margin dynamics.",

keywords = "Deep-water sedimentation processes, Glacigenic debris flows, Basin fan deposits, Trough mouth fan, Subglacial meltwater, West of Shetland, Seismic geomorphology",

author = "Simona Caruso and Vittorio Maselli and Brice Rea and Matteo Spagnolo",

note = "Acknowledgments We acknowledge and thank Siccar Point Energy for permission to use and present their 3D seismic reflection and well data. We are thankful to Vela Software International, IHS, and Schlumberger for granting access to their interpretation and visualisation software Petrosys PRO, Kingdom Suite, and Petrel, respectively. Thanks to Ben Kneller for his interest and insightful discussion on turbidite versus debris flow processes. The authors would like to thank the Editor Michele Rebesco and two anonymous reviewers who helped improve the quality of the manuscript. S. Caruso has been supported by the University of Aberdeen Elphinstone PhD scholarship. V. Maselli acknowledges support from the Natural Sciences and Engineering Research Council of Canada Discovery Grant (RGPIN-2020–04461). ",

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doi = "10.1016/j.margeo.2022.106769",

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AU - Caruso, Simona

AU - Maselli, Vittorio

AU - Rea, Brice

AU - Spagnolo, Matteo

N1 - Acknowledgments We acknowledge and thank Siccar Point Energy for permission to use and present their 3D seismic reflection and well data. We are thankful to Vela Software International, IHS, and Schlumberger for granting access to their interpretation and visualisation software Petrosys PRO, Kingdom Suite, and Petrel, respectively. Thanks to Ben Kneller for his interest and insightful discussion on turbidite versus debris flow processes. The authors would like to thank the Editor Michele Rebesco and two anonymous reviewers who helped improve the quality of the manuscript. S. Caruso has been supported by the University of Aberdeen Elphinstone PhD scholarship. V. Maselli acknowledges support from the Natural Sciences and Engineering Research Council of Canada Discovery Grant (RGPIN-2020–04461).

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N2 - Trough Mouth Fans (TMF) are sedimentary depocenters located at glaciated continental margins and consist predominantly of glacigenic debris flow deposits. The Foula wedge is a Pleistocene TMF accumulated offshore West of Shetland over the Northeast Atlantic margin. This study presents an analysis of a 3D seismic reflection dataset imaging the distal Foula wedge basin fan deposits between 1010 and 1100 m water depth, directly downslope from a gully system which was active untill the end of the last deglaciation. Results reveal, in unprecedented detail, the basal surface of this fan system and its internal complex architecture. Features typical of both debris flow deposits and turbidites are identified, including a basin channel network with linear and diverging erosional features forming distinctive terminal lobes, stacked and backstepping. The study links the seafloor morphology of the basin fan with its subsurface geomorphology, showing connection with the downslope gully system to the east. It presents evidence for a complex distal depositional system on glaciated margins, characterised by heterogeneous sediment delivery processes and deposits. A conceptual evolution model is proposed, with a glacigenic debris flow-dominated TMF at the LGM, subsequently influenced bymeltwater discharges, with deposition occurring as a function of the shelf margin andvised slope paleo-morphology, slope substrate composition, interaction of downslope and along slope processes and ice-margin dynamics.

AB - Trough Mouth Fans (TMF) are sedimentary depocenters located at glaciated continental margins and consist predominantly of glacigenic debris flow deposits. The Foula wedge is a Pleistocene TMF accumulated offshore West of Shetland over the Northeast Atlantic margin. This study presents an analysis of a 3D seismic reflection dataset imaging the distal Foula wedge basin fan deposits between 1010 and 1100 m water depth, directly downslope from a gully system which was active untill the end of the last deglaciation. Results reveal, in unprecedented detail, the basal surface of this fan system and its internal complex architecture. Features typical of both debris flow deposits and turbidites are identified, including a basin channel network with linear and diverging erosional features forming distinctive terminal lobes, stacked and backstepping. The study links the seafloor morphology of the basin fan with its subsurface geomorphology, showing connection with the downslope gully system to the east. It presents evidence for a complex distal depositional system on glaciated margins, characterised by heterogeneous sediment delivery processes and deposits. A conceptual evolution model is proposed, with a glacigenic debris flow-dominated TMF at the LGM, subsequently influenced bymeltwater discharges, with deposition occurring as a function of the shelf margin andvised slope paleo-morphology, slope substrate composition, interaction of downslope and along slope processes and ice-margin dynamics.

KW - Deep-water sedimentation processes

KW - Glacigenic debris flows

KW - Basin fan deposits

KW - Trough mouth fan

KW - Subglacial meltwater

KW - West of Shetland

KW - Seismic geomorphology

U2 - 10.1016/j.margeo.2022.106769

DO - 10.1016/j.margeo.2022.106769

M3 - Article

SN - 0025-3227

VL - 446

JO - Marine Geology

JF - Marine Geology

M1 - 106769

ER -

Deep-water sedimentation processes on a glaciated margin: the Foula Wedge trough mouth fan, West of Shetland.

Abstract

Bibliographical note

Data Availability Statement

Keywords

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The spectacular overburden of the Cambo field

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