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Where and Why Do Submarine Canyons Remain Connected to the Shore During Sea-level Rise? - Insights from Global Topographic Analysis and Bayesian Regression
  • Anne Bernhardt,
  • Wolfgang Schwanghart
Anne Bernhardt
Freie Universit├Ąt Berlin

Corresponding Author:anne.bernhardt@fu-berlin.de

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Wolfgang Schwanghart
University of Potsdam
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Abstract

The efficiency of sediment routing from land to the ocean depends on the position of submarine canyon heads with regard to terrestrial sediment sources. We aim to identify the main controls on whether a submarine canyon head remains connected to terrestrial sediment input during Holocene sea-level rise. Globally, we identified 821 canyon heads that are currently located at the -120m depth contour (the Last Glacial Maximum shoreline) and 188 canyon heads that remained shore-connected during present-day highstand. Regional hotspots of present-day shore connected canyons (SCCs) are the Mediterranean active margin and the Pacific coast of Central and South America. We used 34 terrestrial and marine predictor variables to predict SCC occurrence using Bayesian regression. Our analysis suggests that narrow and steep shelves and steep continental slopes precondition the maintenance of canyon-head connectivity to the shore. Moreover, SCCs occur preferentially along active margins characterized by low-erodibility bedrock and high water discharge.