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GEOPHYSICAL RESEARCH LETTERS, VOL. 34, L20606, doi:10.1029/2007GL031142, 2007

Demise of a submarine canyon? Evidence for highstand infilling on the Waipaoa River continental margin, New Zealand

J. P. Walsh

Department of Geological Sciences, East Carolina University, Greenville, North Carolina, USA


C. R. Alexander

Skidaway Institute of Oceanography, Savannah, Georgia, USA


T. Gerber

Nicholas School of the Environment, Duke University, Durham, North Carolina, USA


A. R. Orpin

National Institute of Water and Atmospheric Research, Wellington, New Zealand


B. W. Sumners

Department of Geological Sciences, East Carolina University, Greenville, North Carolina, USA


Abstract

Submarine canyons are major geomorphologic features on the Earth's surface. Their formation has received considerable debate, but their demise has received less attention. Research of modern canyons with cores and moorings has documented active sediment transport and deposition, but extrapolation of these local observations over larger areas is precluded by complex canyon geomorphology. High-resolution multibeam and chirp data presented here provide convincing evidence of an infilling canyon head on the Waipaoa River margin of New Zealand. Tens of meters of Holocene sediment have accumulated on the outer shelf and in Lachlan canyon as a result of off-shelf sediment transport. Regardless of the ultimate fate of this system over geological time scales, this research demonstrates highstand sedimentation as a possible mechanism for canyon burial and cause of canyon demise, which has important implications for the evolution of canyons globally.

Received 29 June 2007; accepted 24 September 2007; published 31 October 2007.

Keywords: canyon; infilling; Waipaoa.

Index Terms: 3002 Marine Geology and Geophysics: Continental shelf and slope processes (4219); 4863 Oceanography: Biological and Chemical: Sedimentation (1861); 3025 Marine Geology and Geophysics: Marine seismics (0935, 7294); 3022 Marine Geology and Geophysics: Marine sediments: processes and transport.

Subscriber Access to Full Article (Nonsubscribers may purchase for $9.00, Includes print PDF, file size: 384861 bytes)

Citation: Walsh, J. P., C. R. Alexander, T. Gerber, A. R. Orpin, and B. W. Sumners (2007), Demise of a submarine canyon? Evidence for highstand infilling on the Waipaoa River continental margin, New Zealand, Geophys. Res. Lett., 34, L20606, doi:10.1029/2007GL031142.