Details
| Original language | English |
|---|---|
| Number of pages | 18 |
| Edition | 1 |
| Publication status | Published - 30 Sept 2019 |
| Externally published | Yes |
Publication series
| Name | Geological Society Special Publication |
|---|---|
| Publisher | Geological Society of London |
| Volume | 477 |
| ISSN (Print) | 0305-8719 |
Abstract
Many mass transport complexes (MTCs) contain up to kilometre-scale (mega)clasts encased in a debritic matrix. Although many megaclasts are sourced from the headwall areas, the irregular basal shear surfaces of many MTCs indicate that megaclast entrainment during the passage of flows into the deeper basin is also common. However, the mechanisms responsible for the entrainment of large blocks of substrate, and their influence on the longitudinal behaviour of the associated flows, have not been widely considered. We present examples of megaclasts from exhumed MTCs (the Neuquén Basin, Argentina and the Karoo Basin, South Africa) and MTCs imaged in three-dimensional seismic reflection data (Magdalena Fan, offshore Colombia and Santos Basin, offshore Brazil) to investigate these process–product interactions. We show that highly sheared basal surfaces are well developed in distal locations, sometimes extending beyond their associated deposit. This points to deformation and weakening of the substrate ahead of the flow, suggesting that preconditioning of the substrate by distributed shear ahead of, and to the side of, a mass flow could result in the entrainment of large fragments. An improved understanding of the interactions between flow evolution, seabed topography, and the entrainment and abrasion of megaclasts will help to refine estimates of run-out distances, and therefore the geohazard potential of submarine landslides.
ASJC Scopus subject areas
- Environmental Science(all)
- Water Science and Technology
- Engineering(all)
- Ocean Engineering
- Earth and Planetary Sciences(all)
- Geology
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1 ed. 2019. 18 p. (Geological Society Special Publication; Vol. 477).
Research output: Book/Report › Monograph › Research › peer review
}
TY - BOOK
T1 - Entrainment and abrasion of megaclasts during submarine landsliding and their impact on flow behaviour
AU - Hodgson, D.M.
AU - Brooks, H.L.
AU - Ortiz-Karpf, A.
AU - Spychala, Y.
AU - Lee, D.R.
AU - Jackson, C.A.-L.
N1 - Funding information: Funding The Karoo Basin work was carried out as part of the SLOPE 4 consortium research project. We are grateful for financial support from: Anadarko, BHP Billiton, BP, ConocoPhillips, ENGIE, Maersk Oil, Murphy, Nexen, Petrobras, Premier Oil, Shell, Statoil, Total, VNG Norge and Woodside. The Neuquén Basin work was carried out as part of a research project funded by VNG Norge. The offshore Colombia data was funded in part by Colciencias.
PY - 2019/9/30
Y1 - 2019/9/30
N2 - Many mass transport complexes (MTCs) contain up to kilometre-scale (mega)clasts encased in a debritic matrix. Although many megaclasts are sourced from the headwall areas, the irregular basal shear surfaces of many MTCs indicate that megaclast entrainment during the passage of flows into the deeper basin is also common. However, the mechanisms responsible for the entrainment of large blocks of substrate, and their influence on the longitudinal behaviour of the associated flows, have not been widely considered. We present examples of megaclasts from exhumed MTCs (the Neuquén Basin, Argentina and the Karoo Basin, South Africa) and MTCs imaged in three-dimensional seismic reflection data (Magdalena Fan, offshore Colombia and Santos Basin, offshore Brazil) to investigate these process–product interactions. We show that highly sheared basal surfaces are well developed in distal locations, sometimes extending beyond their associated deposit. This points to deformation and weakening of the substrate ahead of the flow, suggesting that preconditioning of the substrate by distributed shear ahead of, and to the side of, a mass flow could result in the entrainment of large fragments. An improved understanding of the interactions between flow evolution, seabed topography, and the entrainment and abrasion of megaclasts will help to refine estimates of run-out distances, and therefore the geohazard potential of submarine landslides.
AB - Many mass transport complexes (MTCs) contain up to kilometre-scale (mega)clasts encased in a debritic matrix. Although many megaclasts are sourced from the headwall areas, the irregular basal shear surfaces of many MTCs indicate that megaclast entrainment during the passage of flows into the deeper basin is also common. However, the mechanisms responsible for the entrainment of large blocks of substrate, and their influence on the longitudinal behaviour of the associated flows, have not been widely considered. We present examples of megaclasts from exhumed MTCs (the Neuquén Basin, Argentina and the Karoo Basin, South Africa) and MTCs imaged in three-dimensional seismic reflection data (Magdalena Fan, offshore Colombia and Santos Basin, offshore Brazil) to investigate these process–product interactions. We show that highly sheared basal surfaces are well developed in distal locations, sometimes extending beyond their associated deposit. This points to deformation and weakening of the substrate ahead of the flow, suggesting that preconditioning of the substrate by distributed shear ahead of, and to the side of, a mass flow could result in the entrainment of large fragments. An improved understanding of the interactions between flow evolution, seabed topography, and the entrainment and abrasion of megaclasts will help to refine estimates of run-out distances, and therefore the geohazard potential of submarine landslides.
UR - http://www.scopus.com/inward/record.url?scp=85076696846&partnerID=8YFLogxK
U2 - 10.1144/sp477.26
DO - 10.1144/sp477.26
M3 - Monograph
T3 - Geological Society Special Publication
BT - Entrainment and abrasion of megaclasts during submarine landsliding and their impact on flow behaviour
ER -