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Sahara Slide: Age, initiation, and processes of a giant submarine slide

Sahara Slide: Age, initiation, and processes of a giant submarine slide
Sahara Slide: Age, initiation, and processes of a giant submarine slide
The Sahara Slide is a giant submarine landslide on the northwest African continental margin. The landslide is located on the open continental slope offshore arid Western Sahara, with a headwall at a water depth of ?2000 m. High primary productivity in surface waters drives accumulation of thick fine-grained pelagic/hemipelagic sediment sequences in the slide source area. Rare but large-scale slope failures, such as the Sahara Slide that remobilized approximately 600 km3 of sediment, are characteristic of this sedimentological setting. Seismic profiles collected from the slide scar reveal a stepped profile with two 100 m high headwalls, suggesting that the slide occurred retrogressively as a slab-type failure. Sediment cores recovered from the slide deposit provide new insights into the process by which the slide eroded and entrained a volcaniclastic sand layer. When this layer was entrained at the base of the slide it became fluidized and resulted in low apparent friction, facilitating the exceptionally long runout of ?900 km. The slide location appears to be controlled by the buried headwall of an older slope failure, and we suggest that the cause of the slide relates to differential sedimentation rates and compaction across these scarps, leading to local increases of pore pressure. Sediment cores yield a date of 50–60 ka for the main slide event, a period of global sea level rise which may have contributed to pore pressure buildup. The link with sea level rising is consistent with other submarine landslides on this margin, drawing attention to this potential hazard during global warming.
1525-2027
Q07014
Georgiopoulou, Aggeliki
1cc90c8c-49e7-4be1-9117-851793dcfe57
Masson, Douglas G.
edd44c8b-38ca-45fb-8d0d-ac8365748a45
Wynn, Russell B.
72ccd765-9240-45f8-9951-4552b497475a
Krastel, Sebastian
4d9bf243-610a-4875-8c03-cd975c9f8542
Georgiopoulou, Aggeliki
1cc90c8c-49e7-4be1-9117-851793dcfe57
Masson, Douglas G.
edd44c8b-38ca-45fb-8d0d-ac8365748a45
Wynn, Russell B.
72ccd765-9240-45f8-9951-4552b497475a
Krastel, Sebastian
4d9bf243-610a-4875-8c03-cd975c9f8542

Georgiopoulou, Aggeliki, Masson, Douglas G., Wynn, Russell B. and Krastel, Sebastian (2010) Sahara Slide: Age, initiation, and processes of a giant submarine slide. Geochemistry, Geophysics, Geosystems, 11 (7), Q07014. (doi:10.1029/2010GC003066).

Record type: Article

Abstract

The Sahara Slide is a giant submarine landslide on the northwest African continental margin. The landslide is located on the open continental slope offshore arid Western Sahara, with a headwall at a water depth of ?2000 m. High primary productivity in surface waters drives accumulation of thick fine-grained pelagic/hemipelagic sediment sequences in the slide source area. Rare but large-scale slope failures, such as the Sahara Slide that remobilized approximately 600 km3 of sediment, are characteristic of this sedimentological setting. Seismic profiles collected from the slide scar reveal a stepped profile with two 100 m high headwalls, suggesting that the slide occurred retrogressively as a slab-type failure. Sediment cores recovered from the slide deposit provide new insights into the process by which the slide eroded and entrained a volcaniclastic sand layer. When this layer was entrained at the base of the slide it became fluidized and resulted in low apparent friction, facilitating the exceptionally long runout of ?900 km. The slide location appears to be controlled by the buried headwall of an older slope failure, and we suggest that the cause of the slide relates to differential sedimentation rates and compaction across these scarps, leading to local increases of pore pressure. Sediment cores yield a date of 50–60 ka for the main slide event, a period of global sea level rise which may have contributed to pore pressure buildup. The link with sea level rising is consistent with other submarine landslides on this margin, drawing attention to this potential hazard during global warming.

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More information

Published date: 2010
Organisations: Marine Geoscience

Identifiers

Local EPrints ID: 172235
URI: http://eprints.soton.ac.uk/id/eprint/172235
ISSN: 1525-2027
PURE UUID: 6ea98eb3-8909-4126-96b7-070c4d95a65d

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Date deposited: 24 Jan 2011 14:46
Last modified: 14 Mar 2024 02:28

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Contributors

Author: Aggeliki Georgiopoulou
Author: Douglas G. Masson
Author: Russell B. Wynn
Author: Sebastian Krastel

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