- journal_title：Journal of the Geological Society
- Contributor：LAWRENCE A. AMY ; BENJAMIN C. KNELLER ; WILLIAM D. McCAFFREY
- Publisher：Geological Society of London
- Date：2007-
- Format：text/html
- Language：en
- Identifier：10.1144/0016-76492005-019
- journal_abbrev：Journal of the Geological Society
- issn：0016-7649
- volume：164
- issue：1
- firstpage：143
- section：Original Article
Basins in which turbidity currents are completely or partially trapped are common in many tectonically active, deep-water settings. Field study of an Eocene–Oligocene turbiditic system in the Peïra Cava area, a sub-basin of the Alpine foreland in southeastern France, allows spatial characterization of a ponded basin fill on the basis of a correlation framework derived from measured outcrop sections and photomosaics. The basin-fill architecture comprises a sand-rich, proximal scour-and-fill facies and a downstream transition to mud-rich, basin-plain turbidite sheet facies. The proximal facies is interpreted to have formed directly downstream of a slope break, where currents were highly erosional during some periods and highly depositional during other periods, as a result of the interacting effects of turbulence enhancement and rapid deceleration. Both the proximal facies and the downstream transition to distal basin-plain facies occur in progressively landward positions at higher stratigraphic levels. The landward shift in depositional facies is likely to have resulted from the basin-floor aggradation and a landward migration of the slope break. This ‘back-stepping’ process may be expected to occur in many ponded turbiditic basins and to produce a similar type of sedimentary architecture.