Saharan Continental Rise: Facies Distribution and Sediment Slides

Masson, Douglas G.; Kidd, Robert B.; Gardner, James V.; Huggett, Q. J.; Weaver, Philip Pe

doi:10.1007/978-1-4684-6500-6_13

Cited by 43 publications

(48 citation statements)

References 22 publications

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“…They lack a single, well-defined headwall scarp, which is here substituted by several sets of small scarps extending over broad areas. The debris flows only involve the first tens of metres of the fine-grain sediment cover but can achieve volumes even larger than those of debris avalanches (Masson et al, 1992).…”

Section: Hints On Mass-wasting Processesmentioning

confidence: 99%

Flank stability and processes off the western Canary Islands: a review from El Hierro and La Palma

Úrgeles¹,

Canals²,

Masson³

2001

Sci. Mar.

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SUMMARY: The morphological characterisation of the western submarine island flanks of El Hierro and La Palma differentiates four type-zones that may give new insights into the evolution of oceanic island slopes. The different type-zones result from the interplay between constructive volcanic processes, hemipelagic settling and volcano collapses. The latter results in massive debris avalanche deposits, which form large volcaniclastic aprons. In most cases, the headwall scarps are clearly exposed on the emerged part of the islands. The events that occurred in the youngest and westernmost islands of El Hierro and La Palma have vertical runouts exceeding 6,000 m and volumes that can reach several hundred km 3 . The landslide frequency for the entire Canaries is one major event per 90 ka. Triggering mechanisms are closely related to magmatic processes. The increase in the shear stress is directly linked with the forceful intrusion of magma along "ridge-rift" systems, while in the western Canary Islands it seems that the main process reducing shear resistance may be related to the rise in pore pressure due to hydrothermal circulation.

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Section: Hints On Mass-wasting Processesmentioning

confidence: 99%

Flank stability and processes off the western Canary Islands: a review from El Hierro and La Palma

Úrgeles¹,

Canals²,

Masson³

2001

Sci. Mar.

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“…Sediment slides and debris flows have been most fully described off the northwest African coast where some cover a great area (Embley, 1976;Jacobi, 1976;Kidd et al, 1986;Masson et al, 1994)..Turbidity currents originating from slope failure may travel considerable distances across the ocean floor, depositing progressively finer sediments as they do so.. Distal turbidites are typically fine grained and carbonate rich and have a higher total organic carbon content (1-3%) than sediments of pelagic origin (Wilson and Wallace, 1990;Stein, 1991). Such deposits are known to blanket the Madeira Abyssal Plain where the Quaternary succession consists of thick turbidite units separated by thin pelagic layers (Weaver and Kuijpers, 1983;Weaver et al, 1986).…”

Section: Dinet Andmentioning

confidence: 99%

“…They clearly influence the abyssal biota since areas of the Madeira Abyssal Plain underlain by turbiditic and pelagic sediments have quite different assemblages of animal traces (Huggett, 1986).. Turbidity currents must have devastated benthic life over large tracts of ocean floor and controlled the nature of recolonizing communities. However, such events have been rare along the northwest African margin with only one major turbidite being deposited, on average, every 30 000 years during the last 730 000 years (Masson et al, 1994)..Hence, all but the most recent turbidites are blanketed by pelagic sediments. Bottom current deposits (contourites) are well developed on the abyssal aprons, for example around the Rockall Plateau (Hill, 1987).…”

Section: Dinet Andmentioning

confidence: 99%

Meiobenthos of the Deep Northeast Atlantic

Vincx¹,

Bett²,

Dinet³

et al. 1994

Advances in Marine Biology

121

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“…Upwelling and bottom-water erosion (Arthur et al, 1979;Sarnthein et al, 1982;Tiedemann et al, 1989;Jacobi and Hayes, 1992) and an increase in turbidites, slides, slumps, and submarine canyon erosion (von Rad and Wissmann, 1982;Masson et al, 1992) have also been noted along the continental margin of northwestern Africa. Current erosion may be responsible for some of these masswasting events at Sites 955 and 956.…”

Section: Quaternary (16 To 0 Ma)mentioning

confidence: 99%

Provenance and sedimentologic variations of turbidite and slump deposits at Sites 955 and 956

Goldstrand¹

1998

Proceedings of the Ocean Drilling Program, 157 Scientific Results

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At two of the seven sites drilled during Leg 157, located south of the Canary Islands (Sites 955 and 956), more than 1000 thinly bedded to finely laminated volcaniclastic and nonvolcaniclastic silt and sand turbidite units interbedded within thick sequences of hemipelagic mud were recovered. The sediments range in age from Pleistocene to middle Miocene. Turbidite deposits composed mostly of volcaniclastic detritus are related to known periods of volcanism in the Canary Islands. The nonvolcaniclastic turbidites include various mixtures of quartz and foraminifer sand and silt derived from the continental margin of northwestern Africa. Shallow marine bioclastic deposits are thicker at Site 956 than at Site 955, suggesting that these sediments were derived from the southern Canary Islands.Although age constraints cannot be precisely defined at these sites, the general trend of sedimentation is consistent with sealevel variations being responsible for transport of the continentally derived turbidites. Quartz-rich turbidite deposits composed of well-rounded, very fine-grained sand were derived from Saharan eolian sands that migrated onto the subaerially exposed continental shelf and were shed into the deep marine environment during falls in sea level. Shallow marine bioclastic and foraminifer-rich turbidites also correspond to periods of sea-level fluctuations. However, the presence of volcaniclastic material within several bioclastic deposits indicates volcanic activity may have been responsible for some of their deposition.Large-scale submarine slumping appears to be more active during periods of intensified bottom currents and upwelling. Additionally, slumping was more frequent at Site 956 on the lower flank of Gran Canaria. Slump block ages are only slightly older than those of the surrounding sediment, and mass movement may have resulted from increased sedimentation and/or earthquakes associated with Canary Islands volcanism.

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Saharan Continental Rise: Facies Distribution and Sediment Slides

Cited by 43 publications

References 22 publications

Flank stability and processes off the western Canary Islands: a review from El Hierro and La Palma

Flank stability and processes off the western Canary Islands: a review from El Hierro and La Palma

Meiobenthos of the Deep Northeast Atlantic

Provenance and sedimentologic variations of turbidite and slump deposits at Sites 955 and 956

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