Three-Dimensional Model of the Rhone Deep-Sea Fan from Sea-Beam Profiles

G. Bellaiche, L. Droz

Our model has been elaborated from the sea-beam map of the Rhone deep-sea fan established from a network of 328 parallel and overlapping sea-beam profiles 40 to 60 km long, issued from the Deltarho-Profans cruises of the R.V. Jean-Charcot. It represents marine areas ranging from -2,580 to -200 m. The area above -200 m (marine and continental) has been constructed from preexisting data.

This model has been built by Szep (Laboratoire de Geodynamique, Villefranche) at a scale of 1/200,000 by superimposing and pasting on a series of cut-out polystyrene sheets. The thickness of these sheets varies from 5 mm (corresponding to 50 m elevation), in the areas shallower than -2,000 m, to 2 mm (20 m elevation) in the deeper areas in order to provide smoother, more precise fan morphology. The resulting vertical exaggeration is 20. The size of the model, in centimeters, is 144 (L) × 78 (W) × 33 (H). It weighs about 15 kg.

All the main features displayed by the sea-beam map are striking: meandering deep central channel, abandoned channels, new fan construction linked with channel avulsion, gravity fault scars, damming salt domes. Other features such as deep, small basins at the foot of the canyons are very clear and illustrate the strength of the erosive processes occurring in these areas.

AAPG Search and Discovery Article #91032©1988 Mediterranean Basins Conference and Exhibition, Nice, France, 25-28 September 1988.