Where and Why Do Submarine Canyons Remain Connected to the Shore During
Sea-level Rise? - Insights from Global Topographic Analysis and Bayesian
Regression
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.