Gravitational, erosional, sedimentary and volcanic processes on the submarine environment of Selvagens Islands (Madeira Archipelago, Portugal)

Santos, Rúben; Quartau, Rui; Silveira, António Brum da; Ramalho, Ricardo S.; Rodrigues, Armanda

doi:10.1016/j.margeo.2019.05.004

Cited by 22 publications

(20 citation statements)

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“…The recognition of widespread fields of bedforms in modern marine volcaniclastic systems at multiple locations worldwide has recently attracted the attention of marine geoscientists, as demonstrated by the growing number of studies in literature (e.g. Wynn et al ., 2000; Wright et al ., 2006; Hoffmann et al ., 2008; Silver et al ., 2009; Gardner, 2010; Leat et al ., 2010; Sisavath et al ., 2011; Casalbore et al ., 2014; Mazuel et al ., 2016; Clare et al ., 2018; Pope et al ., 2018; Quartau et al ., 2018; Santos et al ., 2019). These bedforms can extend over tens of kilometres; individual bedforms having wave heights and wavelengths of hundreds and thousands of metres, respectively.…”

Section: Introductionmentioning

confidence: 99%

Bedforms on the submarine flanks of insular volcanoes: New insights gained from high resolution seafloor surveys

et al. 2020

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A comparative analysis of bedform fields along the submarine flanks of insular volcanoes, characterized by different morpho-structural settings, volcanic and meteo-marine regimes (Vanuatu, Kermadec, Bismark, Madeira and Aeolian archipelagos), is presented here to provide insights on the size distribution, morpho-dynamic and genesis of such bedforms. Two main types of bedforms are recognized according to their size, location and preconditioning/triggering processes. Small-scale bedforms have wavelengths of tens to hundreds of metres and wave heights of metres. Because of their small-size, they are typically not recognizable at water depths greater than 400 m from vessel-mounted bathymetric surveys. Few examples of small-scale bedforms are reported from upper volcanic flanks, where steep gradients commonly hinder their formation. Their

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Section: Introductionmentioning

confidence: 99%

Bedforms on the submarine flanks of insular volcanoes: New insights gained from high resolution seafloor surveys

et al. 2020

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“…3 Throughout the descriptions and discussions above, bedforms are described and interpreted to be evidence of slow-moving sediment creep. However, many recent studies of archipelagic aprons have described bedforms as the result of energetic turbidity currents (e.g., Wynn and Stow, 2002;Pope et al, 2018;Quartau et al, 2018;Santos et al, 2019;Casalbore et al, 2020). Individual French Frigate Shoals edifice and Necker Island edifice bedform crest heights, crest wavelengths, and water depths were measured, and plots are shown in Figures 15 and 20.…”

Section: Discussionmentioning

confidence: 99%

“…Individual French Frigate Shoals edifice and Necker Island edifice bedform crest heights, crest wavelengths, and water depths were measured, and plots are shown in Figures 15 and 20. Wynn and Stow (2002), Pope et al (2018), Santos et al (2019), and Casalbore et al (2020), and references therein discuss criteria to distinguish between bedforms caused by turbidity currents and sediment creep. Table 1 contrasts the differences in morphology and setting discussed in these studies to distinguish bedforms formed by energetic turbidity currents from those formed by slow, gravity-induced sediment deformation that is generally described as creep.…”

Section: Discussionmentioning

confidence: 99%

“…Studies in the 1980s of landslides at seamounts, guyots, and islands used either longrange sidescan sonar (e.g., Moore et al, 1989;Masson et al, 1992) or utilized early versions of multibeam echosounders (MBES) but created only sidescan backscatter images (i.e., Moore et al, 1989;Holcomb and Searle, 1991), bathymetric contour maps (e.g., Hollister et al, 1978;Vogt and Smoot, 1984;Smoot, 1985), or mesh grids (e.g., Taylor et al, 1975Taylor et al, , 1980Smoot, 1982Smoot, , 1983aSmoot, , 1983bSmoot, , 1985. Recently, studies have utilized modern multibeam data (e.g., Deplus et al, 2001;Masson et al, 2002;Mitchell et al, 2002;Bohannon and Gardner, 2004;Silver et al, 2009;Casalbore et al, 2010;Montanaro and Beget, 2011;Watt et al, 2012bWatt et al, , 2014Saint-Ange et al, 2013;Ramalho et al, 2015;Watson et al, 2017;Clare et al, 2018;Counts et al, 2018;Pope et al, 2018;Quartau et al, 2018;Santos et al, 2019;Casalbore et al, 2020) to provide complete, high-resolution digital terrain models of the geomorphology of various archipelagic aprons and submarine landslides. Although archipelagic aprons have never been described from this volcanically dormant area of the Northwest Hawaiian Ridge (Fig.…”

Section: Introductionmentioning

confidence: 99%

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Geomorphometric descriptions of archipelagic aprons off the southern flanks of French Frigate Shoals and Necker Island edifices, Northwest Hawaiian Ridge

Gardner¹,

Calder²,

Armstrong³

2021

GSA Bulletin

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This study describes the geomorphometries of archipelagic aprons on the southern flanks of the French Frigate Shoals and Necker Island edifices on the central Northwest Hawaiian Ridge that are hotspot volcanoes that have been dormant for 10−11 m.y. The archipelagic aprons are related to erosional headwall scarps and gullies on landslide surfaces but also include downslope gravitational features that include slides, debris avalanches, bedform fields, and outrunners. Some outrunners are located 85 km out onto the deep seafloor in water depths of 4900 m. The bedforms are interpreted to be the result of slow downslope sediment creep rather than products of turbidity currents. The archipelagic aprons appear to differ in origin from those off the Hawaiian Islands. The landslides off the Hawaiian Islands occurred because of oversteepening and loading during the constructive phase of the islands whereas the landslides off the French Frigate Shoals and Necker Island edifices may have resulted from vertical tectonics due to the uplift and relaxation of a peripheral bulge or isolated earthquakes long after the edifices passed beyond the hotspot. The lack of pelagic drape in water depths above the 4600 m depth of the local carbonate compensation depth suggests that the archipelagic apron off the French Frigate Shoals edifice is much younger, perhaps Quaternary in age, than that off the Necker Island edifice, which has a 50 m pelagic drape. The pelagic drape off the Necker Island edifice suggests that the landslides may be as old as 9 Ma. The lack of pelagic drape off the French Frigate Shoals edifice suggests that the most recent landslides are more recent, perhaps even Quaternary in age. The presence of a chute-like feature on the mid-flank of the French Frigate Shoals edifice appears to be the result of rejuvenated volcanism that occurred long after the initial volcanism ceased to build the edifice.

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“…As rates of deposition increase, less sediment remains in the water column, resulting in a decrease in the deposition rate farther seaward over the bottomset portion of the clinoforms (Pirmez et al , 1998; Walsh et al , 2004). On narrow shelves in very energetic environments, a large portion of such sediments will ultimately be transported beyond the shelf edge, covering the submarine slopes of the island edifice and feed submarine canyon networks that drain into the deep sea (Ávila et al , 2008; Quartau et al , 2018; Santos et al , 2019); possibly, this process was exacerbated during glacial sea‐level lowstands, when shelves were at their narrowest extension.…”

Section: Introductionmentioning

confidence: 99%

Neogene marine sediments and biota encapsulated between lava flows on Santa Maria Island (Azores, north‐east Atlantic): An interplay between sedimentary, erosional and volcanic processes

et al. 2020

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Sedimentary rocks are rarely preserved on reefless volcanic oceanic islands because their sediments are mostly exported from coastal areas towards the deep sea and such islands typically undergo subsidence. In contrast, the exceptional geological record of the uplifted Santa Maria Island (Azores) provides a unique opportunity to gain insight on such coastal systems. This study focuses on a locality at Ponta do Cedro (eastern Santa Maria Island), which features a series of marine fossiliferous sediments wedged between steep lava deltas. As demonstrated by local structure, these sediments correspond to clinoforms deposited on the steep submarine slope of an active volcanic island, implying transport from shallow waters to greater depths and subsequent colonization by benthic communities. Rapid volcanic progradation eventually sealed the deposits, allowing for their preservation and providing a 3595

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Gravitational, erosional, sedimentary and volcanic processes on the submarine environment of Selvagens Islands (Madeira Archipelago, Portugal)

Cited by 22 publications

References 57 publications

Bedforms on the submarine flanks of insular volcanoes: New insights gained from high resolution seafloor surveys

Bedforms on the submarine flanks of insular volcanoes: New insights gained from high resolution seafloor surveys

Geomorphometric descriptions of archipelagic aprons off the southern flanks of French Frigate Shoals and Necker Island edifices, Northwest Hawaiian Ridge

Neogene marine sediments and biota encapsulated between lava flows on Santa Maria Island (Azores, north‐east Atlantic): An interplay between sedimentary, erosional and volcanic processes

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