1999. "Summary", An Introduction to the Analysis of Ancient Turbidite Basins from an Outcrop Perspective, Emiliano Mutti, Roberto Tinterri, Eduard Remacha, Nicola Mavilla, Stefano Angella, Luca Fava
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In peripheral foreland basins, turbidite systems are characterized by relatively simple depositional settings. The fundamental expression of these systems are huge accumulations of basinal, cyclically-stacked sandstone lobes with an impressive lateral extent. These accumulations, representing potential reservoirs for hydrocarbons, record the main depositional zone of large-volume turbidity currents originated from hyperpycnal flows emanating from flood-dominated deltaic systems along basin margins. Large-scale submarine erosional features, cut into shelfal and slope sediments, acted as conduits of turbidity currents during their basinward motion. Treating turbidite systems in terms of transfer and depositional zones of turbidity currents may avoid much confusion, both conceptually and in practice. Whatever the depositional model, transfer and depositional zones of turbidity currents will exist in each turbidite basin considered. Like in a fluvial system (in the sense of Schumm, 1977), turbidity currents originate (source zone), flow (transfer zone) and will eventually decelerate to the point that all their sediment load will be deposited (depositional zone). Regardless of their size, plan-view and cross-sectional geometry, and facies types, these deposits record the depositional zone of the currents considered.
Turbidite sandstone beds appear to be the deposit of bipartiteturbidity currents consisting of a basal, high-density and overpressuredgranular flow overlain by a low-density, fully turbulent flow. These two flowsare the basic components of a turbidity current whose sediment loadincludes coarse-grained sediment. This concept is supported by boththeoretical and experimental work (e.g., Sanders 1965; Ravenne and Beghin, 1983; Norem et al., 1990). Conglomerate, pebbly-sandstone andrelatively coarse-grained sandstone facies are the typical deposit ofgranular flows. The