Seeking the Shore: Evidence for Active Submarine Canyon Head Incision Due to Coarse Sediment Supply and Focusing of Wave Energy

M. Elliot Smith, Samuel H. Werner, Daniel Buscombe, Noah J. Finnegan, Esther J. Sumner, Erich R. Mueller

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

Submarine flows carve canyons into continental shelves, yet the conditions and events responsible for canyon incision are incompletely understood. Coarse sediment flux has been shown to promote terrestrial bedrock incision via abrasion in rivers, but similar processes in submarine canyons have yet to be systematically documented. We use repeat bathymetry, provenance analysis, wave modeling, and channel network analysis to show that longshore sheltering and wave focusing by the Delgada submarine canyon induce sediment accumulation and elevated wave shear stresses in its headwall region that frequently mobilize coarse bed material. These mobilizations scour bedrock in the headwall and generate abrasive turbidity currents that work to carve the canyon's active channel into bedrock. These findings highlight an important positive feedback between submarine canyons, waves, and sediment supply and suggest that submarine canyons adjacent to wave-dominated, coarse sediment-rich coastlines seek the shoreline through headward incision.

Original languageEnglish (US)
Pages (from-to)12,403-12,413
JournalGeophysical Research Letters
Volume45
Issue number22
DOIs
StatePublished - Nov 28 2018

Keywords

  • connectivity
  • erosion
  • provenance
  • sediment
  • submarine canyons
  • wave focusing

ASJC Scopus subject areas

  • Geophysics
  • Earth and Planetary Sciences(all)

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