The deep-sea Armorican depositional system (Bay of Biscay), a multiple source, vamp model

The deep-sea Armorican depositional system, located in the central part of the Bay of Biscay, is a medium-sized turbidite system with a surface area o f more than 30,000 km(2). The whole system is a mud/sandrich submarine ramp on a passive margin. The medial ramp is characterised by the presence of s ix distinct tributary channels which form three systems: the Guilcher, Croz on and Cornouaille systems. The distal ramp corresponds to divergent braide d secondary channels and associated lobes. Variations in hydrodynamic condi tions on the enter Armorican Shelf during the last climatic cycle are the m ajor factor controlling facies shifts and system growth. Thus, the Armorica n depositional system is a delta-fed submarine ramp during low sea-level gl acial conditions, and an outer shelf-fed submarine ramp at times of sea-lev el rise.