Canyon processes in sediment-undersupplied
margins: A geomorphometric investigation of the Malta Escarpment
submarine canyons. (CUMECS)
Submarine canyons - deep incisions in the continental shelf and slope - play an important role in margin development worldwide and are hotspots of biological activity. Physical processes in submarine canyons are still poorly understood. Current models of canyon formation fail to explain how canyons form in sediment-undersupplied margins or how canyons remain active after disconnecting from terrestrial/littoral sediment sources during high sea level stands. Sediment gravity flows are accepted as a dominant mechanism in canyon erosion, yet their source is not well constrained. Recent studies stress the roles of hydrodynamic and slope failure processes in generating gravity flows and in widening canyons. These processes also regulate habitat diversity and abundance, but the extent of their influence in canyons is unknown and their monitoring is difficult.
CUMECS is an interdisciplinary project
investigating the processes forming canyons in sediment-undersupplied margins
and their influence on benthic habitats. An excellent natural laboratory for such
a study is the Malta Escarpment, central Mediterranean,
which is incised by canyons that have remained largely isolated from inputs of
fluvial/littoral sediments. Our hypothesis is that these canyons are primarily
formed by hydrodynamic processes, widened by mass movements and that their
location is controlled by tectonic structures. To test this hypothesis, we will
carry out a cruise to collect and integrate bathymetry and backscatter data,
sub-bottom and high resolution seismic profiles, sediment cores and ROV imagery
from a Malta Escarpment submarine canyon. We will investigate these data using
geomorphometry and state-of-the-art facilities to identify the nature, origin
and role of the main processes/controls responsible for canyon initiation and
development, to propose a model for canyon evolution in sediment-undersupplied
margins, and to assess the impact of canyon processes on benthic habitats in
such settings.
