The main objective of this paper is to make a morphometric analysis of the submarine canyons of
the Algerian western margin, to discern their possible origin as well as to discuss their evolution,
using high resolution bathymetric data acquired during the MARADJA 1 cruise in 2003.
From the morphometric analysis, it can be seen that where the continental shelf is narrow or even
non-existent canyons are very incised, dendritic and ramified, highly developed, and apparently
very active, whose origin may be associated with sub aerial drainage systems. These canyons are
most likely maintained by gravity flows during the marine transgression, and have concave
longitudinal depth profiles suggesting a mature stage of their evolution. In areas where the
continental shelf is wide, canyons are confined to the continental slope and are disconnected
from a sub aerial river system. They are less incised, less ramified, and poorly developed. The
origin of the slope-confined canyons is rather controlled by retrogressive erosion and small
landslides. These canyons have convex longitudinal depth profiles, suggesting a juvenile stage of
their evolution.
In conclusion, it can be seen that the canyons of the western Algerian margin show changes in
their geometric configuration, from east to west and from the top to the bottom of the continental
slope, which gives it a morphological contrast. Different parameters probably act simultaneously
in time and space to control the location of the canyons, their initiation and evolution on the
margin, notably sea level variations, sediment supply, margin morphology, geodynamic history
of the margin and compressive tectonics.
Key words:
Western Algerian Margin, Submarine canyons, Morphometric analysis, Retrogressive erosion,
Compressive tectonics.