A global analysis of controls on submarine-canyon geomorphology

Abstract

The role of possible controlling factors in influencing the geomorphology of submarine canyons has been investigated using a database of 282 globally distributed modern examples collated from the literature, open-source worldwide bathymetry and satellite imagery. Canyon geomorphology has been characterized quantitatively in terms of maximum and average canyon dimensions, canyon sinuosity, the average canyon thalweg gradient, and maximum canyon sidewall steepness. Geomorphological variations with respect to position of the canyon apex relative to the shelf break, continental-margin type, terrestrial source-to-sink system setting, oceanographic environment, and climate zones have been assessed. Scaling relationships between canyon morphometric parameters, and between them and attributes of their physiographic setting, their terrestrial catchments, and attributes of continental shelves and slopes have been quantified.Key findings are as follows: (i) a number of scaling relationships describing canyon morphometry (e.g. scaling between maximum canyon dimensions, relationships of maximum canyon sidewall steepness with maximum canyon width and depth) can be recognized globally, suggesting their general predictive value; (ii) possible causal links are identified between hydrodynamic processes (e.g. upwelling, longshore- and along-slope currents) and canyon morphology; (iii) potential predictors of canyon geomorphology include whether a canyon is incised into the shelf or confined to the slope, the continental-margin type, the oceanographic environment, latitude, and shelf-break depth; (iv) similarity in maximum width-to-maximum depth ratios across all settings suggests that the relative magnitudes of canyon-margin erosion and intra-canyon deposition do not vary greatly depending on setting or canyon size.The relationships between canyon geomorphology and environmental variables identified in this study may be incorporated into conceptual models describing canyon geomorphology and its relationship to other elements of deep-water systems, and into its broader source-to-sink context.

Extending morphometric scaling relationships: the role of bankfull width in unifying subaquatic channel morphologies

“…While advancements in measurement techniques in the last decades have provided insights into these flows, their direct observation remains a challenge (Paull et al, 2018;Talling et al, 2023). Therefore, for most subaquatic sediment conduits, only bathymetric data of varying resolution is available (Bührig et al, 2022b). Thus, the analysis of their morphology, enabled by the ever-growing amount of bathymetric data, emerges as a crucial approach for understanding the evolution of these subaquatic sediment conduits and their associated turbidity currents (Peakall et al, 2012;Konsoer et al, 2013;Shumaker et al, 2018;Lemay et al, 2020;Bührig et al, 2022b).…”