Huge
David
, Besson1, Parize Olivier1,
Dalrymple Robert W2, James Noel2, Reynaud JeanYves3,
Rubino Jean-Loup4 (1) Ecole Nationale Superieure des Mines de Paris, Fontainebleau Cedex, France
(2) Queen’s University, Kingston (3) Museum National d’Histoire Naturelle, Paris, France (4)
Total, Pau Cedex, France
Ten depositional
sequences can be recognized in the Miocene South East Alps foreland basin. They
belong to the Neogene cycle, which evolved from peri-reefal environments to siliciclastic
coastal and fluvial systems. Geometrical relations of these sequences allow us
to identify three huge IVSs, respectively dated
Lower, Middle and Upper Miocene. These huge IVSs (up
to 100 km long and up to 300 m deep) are related to geodynamic foreland basin
evolution and constitute major potential stratigraphics
traps. The Lower Miocene IVS cuts most of the East-West Middle Eocene (Provençal) folds and are generally localized along Oligocene
extensional structures. This first IVS is linked to the basal foreland
unconformity. It presents a compound cool-water carbonates Incised-Valleys Fill
(IVFs)with deep erosional sequence boundaries underlined by diagenetic features. Lower Miocene deposits were also
inverted and the associated compound IVS was re-incised between Burdigalian and Langhian. This
younger incision stage occurs perpendicularly to the first and is linked to a
sea level drop, strongly enhanced by regional uplift. This foreland basin
uplift is explained by shortening rate increase, shown by fold growing, coeval
with the end of the