Long-term denudation of ocean crust in the central North Atlantic Ocean

Tucholke, Brian E.; Stewart, W.K.; Kleinrock, Martin C.

doi:10.1130/0091-7613(1997)025<0171:ltdooc>2.3.co;2

Cited by 38 publications

(27 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Circular embayments were also observed in other seamounts but their circular morphologies are more readily attributed to caldera collapse [ Hammond , 1997]. Therefore although deep‐tow side‐scan sonar images commonly show gullying of the steep flanks of seamounts [ Fornari et al , 1984] probably caused by small slope failures and other superficial erosional processes [ Tucholke et al , 1997], larger failures sufficient to indent seamount flanks are rare. Considering the spatial resolution of multibeam data for these water depths (100–150 m), the lack of landslides is not an artifact of resolution and indicates that mid‐ocean ridge volcanoes are genuinely more stable than the other edifices described below.…”

Section: Island and Seamount Geology And Morphological Observationsmentioning

confidence: 99%

Susceptibility of mid‐ocean ridge volcanic islands and seamounts to large‐scale landsliding

Mitchell

2003

J. Geophys. Res.

View full text Add to dashboard Cite

[1] With a view to assessing the incidence of large-scale landsliding, a morphologic database was created for volcanic islands and seamounts on young oceanic lithosphere. The database included 44 mid-ocean ridge seamounts, Jasper seamount and the islands of Ascension, Bouvet, Guadalupe, and several of the Galapagos and Azores Islands, supplemented with published reports from a further five volcanic edifices. The data reveal that major landslides are common on edifices taller than 2500 m but are rare in shorter edifices, implying a threshold of instability at around 2500 m. A number of causes of this threshold are discussed. For example, many structures taller than 2500 m are, or were originally, volcanic islands, and therefore their flanks probably include extensive weak hyaloclastite built up from lava-sea interactions around coasts. Compaction of hyaloclastites in larger edifices lead to regions of low permeability, which may help to explain the more deeply seated slope failures. It is intriguing that the threshold also coincides with the edifice height at which volcanic ridges become observable, a stage at which dike intrusion is probably common because slope oversteepening or excess pore pressure associated with dike intrusions have been proposed elsewhere as landslide triggers. The current indications of landsliding reveal no observable relation to rainfall, as landslides occur equally in wet and dry climates, and no relation to tectonic setting, as there are relatively few major landslides in the seismically active Azores group.INDEX TERMS: 3035 Marine Geology and Geophysics: Midocean ridge processes; 3022 Marine Geology and Geophysics: Marine sediments-processes and transport; 8499 Volcanology: General or miscellaneous; KEYWORDS: landslides, volcanic debris avalanche, slope stability, multibeam sonar, side-scan sonar Citation: Mitchell, N. C., Susceptibility of mid-ocean ridge volcanic islands and seamounts to large-scale landsliding,

show abstract

Section: Island and Seamount Geology And Morphological Observationsmentioning

confidence: 99%

Susceptibility of mid‐ocean ridge volcanic islands and seamounts to large‐scale landsliding

Mitchell

2003

J. Geophys. Res.

View full text Add to dashboard Cite

show abstract

“…Tucholke et al . [] described kilometer‐scaled slope failures and slumps in deep tow sidescan sonar data acquired off‐axis of the Mid‐Atlantic Ridge (MAR). Searle et al .…”

Section: Introductionmentioning

confidence: 99%

High‐resolution bathymetry reveals contrasting landslide activity shaping the walls of the Mid‐Atlantic Ridge axial valley

Cannat

Mangeney

Ondréas

et al. 2013

Geochem Geophys Geosyst

View full text Add to dashboard Cite

[1] Axial valleys are found along most slow-spreading mid-ocean ridges and are one of the most prominent topographic features on Earth. In this paper, we present the first deep-tow swath bathymetry for the axial valley walls of the Mid-Atlantic Ridge. These data allow us to analyze axial valley wall morphology with a very high resolution (0.5 to 1 m compared to ≥ 50 m for shipboard multibeam bathymetry), revealing the role played by landslides. Slow-spreading ridge axial valleys also commonly expose mantle-derived serpentinized peridotites in the footwalls of large offset normal faults (detachments). In our map of the Ashadze area (lat. 13 N), ultramafic outcrops have an average slope of 18 and behave as sliding deformable rock masses, with little fragmentation. By contrast, the basaltic seafloor in the Krasnov area (lat. 16 38 0 N) has an average slope of 32 and the erosion of the steep basaltic rock faces leads to extensive fragmentation, forming debris with morphologies consistent with noncohesive granular flow. Comparison with laboratory experiments suggests that the repose angle for this basaltic debris is > 25. We discuss the interplay between the normal faults that bound the axial valley and the observed mass wasting processes. We propose that, along axial valley walls where serpentinized peridotites are exposed by detachment faults, mass wasting results in average slopes ≤ 20 , even in places where the emergence angle of the detachment is larger.

show abstract

“…If true, this is the first quantitative characterization of this process. This mass wasting, in the form of canyon cutting, slumps and slides, tends to occur orthogonal to the strike of fault scarps and abyssal hills [Tucholke, et al, 1997a]. The canyons are of the order of a few hundred meters wide.…”

Section: Spectral Analysis Of Profilesmentioning

confidence: 99%

Multiscale spectral analysis of bathymetry on the flank of the Mid‐Atlantic Ridge: Modification of the seafloor by mass wasting and sedimentation

Goff¹,

Tucholke

1997

J. Geophys. Res.

Self Cite

View full text Add to dashboard Cite

Abstract. The results of a multiscale spectral analysis of bathymetric data on the flank of the Mid-Atlantic Ridge are described. Data were collected during two cruises using Hydrosweep multibeam (tens of kilometers to -0.2 km scale range) and Mesotech scanning pencil-beam sonar attached to remotely operated vehicle Jason (-1 km to -0.5 m scale range). These data are augmented by visual data which enabled us to identify bathymetric profiles which are over unsedimented or thinly sedimented crust. Our analysis, therefore, is focused primarily on statistical characterization of basement morphology. Work is concentrated at two sites: site B on -24 Ma crust in an outside-corner setting, and site D on -3 Ma crust in an inside-comer setting. At site B we find that an anisotropic, band-limited fractal model (i.e., the "von Kfirmfin" model proposed for abyssal hill morphology by Goffand Jordan [1988]) is not sufficient to describe the full range of scales observed in this study. Our observations differ from this model in two ways: (1) strike and cross-strike (dip) spectral properties converge for wavelengths smaller than -300 m, and (2) in both strike and dip directions the fractal dimension changes at -10 m wavelength, from -1.27 at larger scales to -1.0 at smaller scales. The convergence of strike and dip spectral properties appears to be associated with destruction of ridge-parallel fault scarps by mass wasting, which develops canyon-like incisions that cross scarps at high angles. The change in fractal dimension at -10 m scale appears to be related to a minimum spacing of significant slope breaks associated with scarps which are created by faulting and mass wasting. At site D, although there is no significant abyssal hill anisotropy, the spectral properties at all scales are consistent with the von Kfirmfin model. The fractal dimension at this site (-1.15) is less than at site B. This difference may be reflect different morphology related to crustal formation at inside-corner versus outside-comer position or, more likely, differences in the degree of mass wasting. The smoothing of seafloor morphology by sediments is evident in Hydrosweep periodograms where, relative to basement roughness, spectral power decreases progressively with decreasing wavelength.

show abstract

Long-term denudation of ocean crust in the central North Atlantic Ocean

Cited by 38 publications

References 0 publications

Susceptibility of mid‐ocean ridge volcanic islands and seamounts to large‐scale landsliding

Susceptibility of mid‐ocean ridge volcanic islands and seamounts to large‐scale landsliding

High‐resolution bathymetry reveals contrasting landslide activity shaping the walls of the Mid‐Atlantic Ridge axial valley

Multiscale spectral analysis of bathymetry on the flank of the Mid‐Atlantic Ridge: Modification of the seafloor by mass wasting and sedimentation

Contact Info

Product

Resources

About