How Sand Gets to the Bottom of the Sea: Turbidity Currents and Deep Water Oil and Gas Reservoirs

Subaqueous turbidity currents may be the dominant mechanism by which sediments are moved from continents into the deep ocean; these flows are critical in the formation of submarine canyons and corresponding submarine fans. Sediments deposited in these settings can, under the right circumstances, assume economic importance as deep water oil and gas reservoirs. In 1986 Parker, Fukushima, and Pantin introduced a depth-averaged mechanical model for these currents, intending to identify the circumstances under which the erosion of underlying material by a turbidity current could lead to an “auto-igniting” sustainable flow. We use a simplified version of their model to map a global regime diagram for these flows as a function of the Richardson and Rouse numbers of the flows; in different segments of this diagram the flows are predominantly depositional, erosional, or bypass in nature. We identify those features of microscopic erosion, deposition, and clear-water entrainment physics that control these large-scale stratigraphic properties.