Abstract/Excerpt

Deterministic, Process Based Modeling of the Deepwater Fill of the Peïra Cava Basin, SE France

Romain Rouzairol¹, Riccardo Basani¹, Ernst W. M. Hansen¹, John A. Howell², and Tor E. Aas³
¹Complex Flow Design AS, Trondheim, Sør Trøndelag, Norway
²CIPR, Bergen, Norway
³Statoil, Stavanger, Norway

Basins in which turbidity currents are completely or partially trapped are common in many tectonically active, deep-water settings. The Eocene-Oligocene Grès d’Annot Formation which crops-out in the Peïra Cava region of south-eastern France is a 1200 m thick succession of sandstones and mudstones deposited in a confined, synclinal sub-basin plunging to the north. The Peïra Cava turbidite system is dominated by interceded high- and low-concentration turbidity deposits with several marker beds that can be correlated throughout the basin fill, providing a robust stratigraphic framework for analysis (Amy et al, 2007).

Using deterministic process based simulations it is possible to recreate the flow events that deposited the basin fill. The aim of the present study to test this methodology and investigate the role of the confinement, relief, and the size of the turbidity currents events required to reproduce the observed stratigraphy. MassFLOW-3D™ is a computational fluid dynamic (CFD) software for the numerical simulation of the physical equations describing fluid flow and sediment transport for turbidity currents. The software has been developed to model erosion, deposition, and transport of sediment in high and low-density turbidity currents, solving full 3D transient Navier–Stokes equations by a finite-volume-finite-differences method, in a fixed Eulerian rectangular grid. Flows are simulated on a structural restored, back-stripped and decompacted palaeo-bathymetry. Given that confinement, tilting and topography are key parameters for the development of turbidity currents and their deposits particular attention was given to recreating by-pass, fill-spill and deflection phenomena, documented in the outcropping succession (Amy et al, 2007; Aas et al., 2010).