--> ABSTRACT: Detailed Architecture and Facies Deposits on a Sand-Rich Deep-Sea Fan (Var, Northwestern Mediterranean), by B. Savoye, P. Cochonat, D. J. W. Piper, and H. Nelson; #91021 (2010)

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Detailed Architecture and Facies Deposits on a Sand-Rich Deep-Sea Fan (Var, Northwestern Mediterranean)

SAVOYE, BRUNO, PIERRE COCHONAT, DAVID J. W. PIPER, and HANS NELSON

The sand-rich Var submarine Fan initiates off Nice, France, extends 230 km to the southeast, and then deposits a distal lobe (80 x 40 km) that parallels the northwestern base of the Corsican continental slope.

Detailed observations were carried out during several surveys conducted from the source area to the distal part of the Var fan lobe. The fan has a morphology suggesting important deposition from both sandy and muddy turbidity currents. Deposition has continued during the Holocene, partly by hyperpycnal flows. Many Holocene turbidites have been observed in cores on the levees. A submarine slide occured in 1979, during landfilling operations to extend Nice airport, resulting in a tsunami and cable breaks near and across the lower Var fan valley.

Deep-water sidescan sonar images and submersible dives showed fresh gravel waves within the upper valley. Backscattering changes of the sonar images along the middle fan valley point out the limit of the sand deposition. Features like sand ridges and erosional scars are observed downslope the fan valley, suggesting that turbidity currents are powerful enough to rework the sea-floor. The distal lobe has a single channel with smaller distributaries, displaying a goose foot like pattern. Recent cores and in situ measurements have been made in the lobe area. The estimated sand to shale ratio averages 8.6:1 in the Holocene highstand deposits and massive sand bodies have been observed.

Such a setting could provide a good case study for large fossil continuous reservoirs.

AAPG Search and Discovery Article #91021©1997 AAPG Annual Convention, Dallas, Texas.