Holocene depositional history of a microtidal cuspate foreland cape: Cape Lookout, North Carolina

Moslow, Thomas F.; Heron, S. Duncan

doi:10.1016/0025-3227(81)90084-0

Cited by 31 publications

(12 citation statements)

References 20 publications

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“…However, even small gradients in alongshore sediment flux easily overwhelm rates of cross‐shore transport due to sea level changes [ Cowell et al , 1995]; a general landward shoreline retreat maintaining a defined shoreface during sea level rise could be superimposed without greatly altering the results shown here. During lowstands, abandoned cuspate shorelines [ Moslow and Heron , 1981] may remain until sea level rises again, affecting subsequent shoreline development, possibly “jumpstarting” the evolution of cuspate coasts. Model results show that, even on geologic timescales, regression and transgression could occur simultaneously along different portions of a cuspate coast even in the absence of a sediment source or along‐coast differences in rates of sea level change.…”

Section: Discussionmentioning

confidence: 99%

High‐angle wave instability and emergent shoreline shapes: 1. Modeling of sand waves, flying spits, and capes

2006

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[1] Contrary to traditional findings, the deepwater angle of wave approach strongly affects plan view coastal evolution, giving rise to an antidiffusional ''high wave angle'' instability for sufficiently oblique deepwater waves (with angles between wave crests and the shoreline trend larger than the value that maximizes alongshore sediment transport, $45°). A one-contour-line numerical model shows that a predominance of high-angle waves can cause a shoreline to self-organize into regular, quasiperiodic shapes similar to those found along many natural coasts at scales ranging from kilometers to hundreds of kilometers. The numerical model has been updated from a previous version to include a formulation for the widening of an overly thin barrier by the process of barrier overwash, which is assumed to maintain a minimum barrier width. Systematic analysis shows that the wave climate determines the form of coastal response. For nearly symmetric wave climates (small net alongshore sediment transport), cuspate coasts develop that exhibit increasing relative cross-shore amplitude and pointier tips as the proportion of high-angle waves is increased. For asymmetrical wave climates, shoreline features migrate in the downdrift direction, either as subtle alongshore sand waves or as offshore-extending ''flying spits,'' depending on the proportion of high-angle waves. Numerical analyses further show that the rate that the alongshore scale of model features increases through merging follows a diffusional temporal scale over several orders of magnitude, a rate that is insensitive to the proportion of high-angle waves. The proportion of high-angle waves determines the offshore versus alongshore aspect ratio of selforganized shoreline undulations.

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Section: Discussionmentioning

confidence: 99%

High‐angle wave instability and emergent shoreline shapes: 1. Modeling of sand waves, flying spits, and capes

2006

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“…As the model does not explicitly include sea level changes, this suggests that several sea level highstands would be required for the capes to form from a hypothetical approximately straight coast. In this scenario, as sea level rises at the start of each interglacial period, the shoreline would likely intercept a variegated coast with existing cuspate shapes [ White , 1966; Moslow and Heron , 1981] that could be affected by river downcutting and deltaic deposition during glacial lowstands. Deltas, as well as inherited capes, could act as finite‐amplitude perturbations for the high‐angle wave instability.…”

Section: Model Predictions and Natural Wave Climatesmentioning

confidence: 99%

High‐angle wave instability and emergent shoreline shapes: 2. Wave climate analysis and comparisons to nature

2006

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[1] Recent research has revealed that the plan view evolution of a coast due to gradients in alongshore sediment transport is highly dependant upon the angles at which waves approach the shore, giving rise to an instability in shoreline shape that can generate different types of naturally occurring coastal landforms, including capes, flying spits, and alongshore sand waves. This instability merely requires that alongshore sediment flux is maximized for a given deepwater wave angle, a maximum that occurs between 35°and 50°for several common alongshore sediment transport formulae. Here we introduce metrics that sum over records of wave data to quantify the long-term stability of wave climates and to investigate how wave climates change along a coast. For Long Point, a flying spit on the north shore of Lake Erie, Canada, wave climate metrics suggest that unstable waves have shaped the spit and, furthermore, that smaller-scale alongshore sand waves occur along the spit at the same locations where the wave climate becomes unstable. A shoreline aligned along the trend of the Carolina Capes, United States, would be dominated by high-angle waves; numerical simulations driven by a comparable wave climate develop a similarly shaped cuspate coast. Local wave climates along these simulated capes and the Carolina Capes show similar trends: Shoreline reorientation and shadowing from neighboring capes causes most of the coast to experience locally stable wave climates despite regional instability.

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“…Many Holocene coastal depositional reconstructions have used radiocarbon dating of shell material included in shoreface sediment facies (Moslow and Heron, 1981;Nummendal, 1983). In southeastern Australia radiocarbon dates have provided the basis for chronological interpretation of Quaternary sea-level changes (Sloss et al, 2007;Lewis et al, 2013;Murray-Wallace and Woodroffe, 2014).…”

Section: Introductionmentioning

confidence: 99%

Towards more robust chronologies of coastal progradation: Optically stimulated luminescence ages for the coastal plain at Moruya, south-eastern Australia

et al. 2014

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2015). Towards more robust chronologies of coastal progradation: optically stimulated luminescence ages for the coastal plain at Moruya, south-eastern Australia. The Holocene: a major interdisciplinary journal focusing on recent environmental change, 25 (3), 536-546.Towards more robust chronologies of coastal progradation: optically stimulated luminescence ages for the coastal plain at Moruya, southeastern Australia AbstractAccurate chronologies are fundamental for detailed analysis of palaeoenvironmental conditions, archaeological reconstructions and investigations of Holocene coastal morphological changes. Chronological data enable estimation of rates of shoreline progradation, and provide appropriate context for forecasting future coastal changes. A previously reported radiocarbon chronology for the Moruya coastal plain in southeastern Australia indicated a decelerating overall rate of progradation with minimal net seaward shoreline movement in the past ~2500 years. Single-grain and multi-grain aliquot optically stimulated luminescence (OSL) analyses demonstrate that marine sands from this region have excellent luminescence characteristics. A series of OSL ages across this coastal barrier indicates a remarkably linear trend of Holocene shoreline progradation. The linear trend of seaward shoreline movement indicates that the barrier has grown at an average rate of 0.27 m/yr with successive ridge formation every ~110 years. The oldest ridge on the barrier appears to correspond to cessation of rapid post-glacial sea-level rise, and the large foredune at the seaward margin of the barrier is chronologies, in Australia and around the world, where they have been based on radiocarbon dating of shell hash.

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Holocene depositional history of a microtidal cuspate foreland cape: Cape Lookout, North Carolina

Cited by 31 publications

References 20 publications

High‐angle wave instability and emergent shoreline shapes: 1. Modeling of sand waves, flying spits, and capes

High‐angle wave instability and emergent shoreline shapes: 1. Modeling of sand waves, flying spits, and capes

High‐angle wave instability and emergent shoreline shapes: 2. Wave climate analysis and comparisons to nature

Towards more robust chronologies of coastal progradation: Optically stimulated luminescence ages for the coastal plain at Moruya, south-eastern Australia

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