Model for the sigmoidal curvature of submarine slopes

Schlager, Wolfgang; Adams, Erwin W.

doi:10.1130/0091-7613(2001)029<0883:mftsco>2.0.co;2

Cited by 46 publications

(38 citation statements)

References 14 publications

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“…Internal waves documented along the modern northern Carnarvon Basin (Holloway, 1984) may also contribute to sediment transportation by (1) resuspending sediment, allowing redistribution by weaker shelf/slope currents (Cacchione and Southard, 1974;Butman et al, 1979) and (2) generating and maintaining nepheloid layers on the uppermost slope (Cacchione and Drake, 1986). Integrated over time, these processes round the clinoform rollovers, as observed (Figures 3,9,12) (Schlager and Adams, 2001).…”

mentioning

confidence: 70%

Progradation along a deeply submerged Oligocene–Miocene heterozoan carbonate shelf: How sensitive are clinoforms to sea level variations?

Cathro

Austin

Moss³

2003

Bulletin

121

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We combine two-and three-dimensional seismic stratigraphic interpretation with paleobathymetric analysis from benthic foraminifera to understand the genetic significance of prominent seismic discontinuity surfaces typically mapped as sequence boundaries and flooding surfaces in the late Paleogene-early Neogene northern Carnarvon Basin.The progradational succession, dominated by heterozoan carbonate sediments, is divided into 5 northwest-prograding clinoformal sequences and 19 subsequences. Clinoform fronts progress from smooth to highly dissected, with intense gullying apparent only after the middle Miocene optimum. Once initiated, gullies become the focus for sediment distribution across the front. Bottomsets remain relatively sediment starved without the development of aprons on the lower slope and basin. Small-scale variability suggests heterogeneous sediment dispersal through the slope conduits. Alongstrike sediment transport superimposed on progradation changes from southwest directed in the late Oligocene to northeast directed in the late middle Miocene, suggesting a major reorganization of circulation in the southeastern Indian Ocean.Prominent seismic discontinuity surfaces represent both intervals of shallow paleowater depth and flooding of the shelf. Partial exposure of the shelf indicated by karst morphology is coeval, with middle to outer neritic paleowater depths on the outer shelf. Instead of building to sea level, progradation occurs with shelf paleowater depths at the clinoform rollover greater than 100 m. Therefore, in the northern Carnarvon Basin, onlap onto the clinoform front is not coastal, and the sensitivity of the clinoforms to sea level changes is muted.

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mentioning

confidence: 70%

Progradation along a deeply submerged Oligocene–Miocene heterozoan carbonate shelf: How sensitive are clinoforms to sea level variations?

Cathro

Austin

Moss³

2003

Bulletin

121

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“…Physically, this reflects the fact that sediment can be moved more easily on a steeper slope (e.g., by currents). Morphodynamic diffusion models have been applied to delta fronts [ Kenyon and Turcotte , 1985], subaqueous deltas [ Friedrichs and Wright , 2004], and continental margins [ Jordan and Flemings , 1991; Schlager and Adams , 2001]. (These examples include both linear models, which assume constant diffusivity, and nonlinear models, which parameterize D as a function of wave orbital velocities).…”

Section: Application To Modern and Ancient Clinoform Systemsmentioning

confidence: 99%

Overpressure and slope stability in prograding clinoforms: Implications for marine morphodynamics

Wolinsky¹,

Pratson²

2007

J. Geophys. Res.

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[1] Rapid deposition of fine-grained sediments can lead to overpressure buildup along the fronts of prograding sedimentary bodies (clinoforms) ranging from deltas to continental margins. Overpressure reduces shear strength, which can lead to failure of submarine slopes, so that overpressure prediction is potentially of fundamental importance to marine morphodynamics. We generalize one-dimensional overpressure theory to migrating clinoforms where deposition is highly localized in space and time, and show that overpressure is characterized by a dimensionless loading intensity, the Gibson number (given by the product of sediment supply and slope, divided by sediment hydraulic diffusivity). Our results show that compared to terrestrial slopes, slope stability in overpressured clinoforms is especially sensitive to foreset steepness, which directly affects loading intensity. The utility of our theory is demonstrated by application to modern and ancient clinoforms with documented slope failures. This analysis suggests that (1) most muddy clinoforms will have significant overpressure, (2) many delta fronts and continental margins prograde at a limiting slope threshold for deep-seated landsliding, and (3) shallow overpressure and near-surface liquefaction may contribute to mobilization of fluid muds which actively prograde subaqueous deltas. We derive quantitative relationships between sediment supply and slope for clinoforms prograding at limiting equilibrium. Importantly, our results suggest that slope is an inverse function of sediment supply in these systems, implying that commonly used diffusive morphodynamics approaches may be inappropriate.

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“…The angular nature of the shelf-edge suggests progradation occurred across a relatively low-energy environment and that the transition between current driven and gravity driven transport regimes was abrupt ( Fig. 2A; Schlager and Adams, 2001). Assuming mass flows are sourced from the upper to middle slope, the wedge of Pleistocene shelf-edge sediment is a likely source for erosive turbidity flows that bypass the middle and lower slopes.…”

Section: Mid-atlantic (Group-4; Areas 13-17)mentioning

confidence: 99%

“…Past studies have proposed that systematic relationships exist between the major governing processes, such as modern sediment supply, and the shape of the resulting continental margin (Pratson and Haxby, 1996;O'Grady et al, 2000;Goff, 2001). Other studies have described relationships between margin morphology and various sedimentary parameters, including sedimentary texture (Schlager and Camber, 1986;Kenter, 1990), sediment supply (Kenyon and Turcotte, 1985;Orton and Reading, 1993) and sediment transport mechanisms (Galloway, 1998;Adams and Schlager, 2000;Schlager and Adams, 2001;Cacchione et al, 2002). However, in order to assess the relative contributions of these processes to shaping the modern-day margin morphology, one must also establish the relative importance of pre-existing physiography and antecedent geology.…”

Section: Introductionmentioning

confidence: 99%

“…Slope depositional systems respond to variations in physiography and environmental conditions by adjusting their loci of erosion and deposition. For example, the curvature of the shelf-edge rollover is largely controlled by the environmental energy conditions (Mitchum et al, 1977;Adams and Schlager, 2000;Schlager and Adams, 2001): regions with weak currents tend to be associated with abrupt, or oblique, rollover profiles Marine Geology 338 (2013) 46-63 Fig. 1.…”

Section: Slope Depositional Systemsmentioning

confidence: 99%

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Geomorphic characterization of the U.S. Atlantic continental margin

2013

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The increasing volume of multibeam bathymetry data collected along continental margins is providing new opportunities to study the feedbacks between sedimentary and oceanographic processes and seafloor morphology. Attempts to develop simple guidelines that describe the relationships between form and process often overlook the importance of inherited physiography in slope depositional systems. Here, we use multibeam bathymetry data and seismic reflection profiles spanning the U.S. Atlantic outer continental shelf, slope and rise from Cape Hatteras to New England to quantify the broad-scale, across-margin morphological variation. Morphometric analyses suggest the margin can be divided into four basic categories that roughly align with Quaternary sedimentary provinces. Within each category, Quaternary sedimentary processes exerted heavy modification of submarine canyons, landslide complexes and the broad-scale morphology of the continental rise, but they appear to have preserved much of the pre-Quaternary, across-margin shape of the continental slope. Without detailed constraints on the substrate structure, first-order morphological categorization the U.S. Atlantic margin does not provide a reliable framework for predicting relationships between form and process.Published by Elsevier B.V.

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Model for the sigmoidal curvature of submarine slopes

Cited by 46 publications

References 14 publications

Progradation along a deeply submerged Oligocene–Miocene heterozoan carbonate shelf: How sensitive are clinoforms to sea level variations?

Progradation along a deeply submerged Oligocene–Miocene heterozoan carbonate shelf: How sensitive are clinoforms to sea level variations?

Overpressure and slope stability in prograding clinoforms: Implications for marine morphodynamics

Geomorphic characterization of the U.S. Atlantic continental margin

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