Surging Versus Continuous Turbidity Currents: Flow Dynamics and Deposits in an Experimental Intraslope Minibasin

Abstract

Small intraslope basins (ϳ 100 km 2 ), or ''minibasins,'' such as those found on the continental slope of the Gulf of Mexico, have been filled predominantly by turbidity currents. Each minibasin is the result of local subsidence and is partially or completely isolated from neighboring basins by ridges formed from compensational uplift. We undertook a series of experiments to investigate the relationship between the flow dynamics of turbidity currents entering a minibasin and the stratal architecture of their deposits. The experiments were performed using continuous-feed turbidity currents and surge-feed turbidity currents. A dimensionless ponding number is developed to compare the geometry of the deposits with the dynamics of the flows that filled the basins. The experimental surging turbidity currents created a deposit that was notably more ponded than the deposits of continuous turbidity currents.

Experimental modeling of gravity underflow in a sinuous submerged channel

“…On the basis of these numbers, the inlet condition can be classified as turbulent subcritical flow. The flow remained subcritical along the entire channel length as indicated by the estimated Richardson number = 1.77 at the bend apex and the observation of a nearly glassy interface between the current and the ambient water above it [Lamb et al, 2004]. In the following sections velocity and turbulence structures of the gravity underflow obtained from measurements at different sections are presented.…”

Influence of flow containment and substrate entrainment upon sandy hybrid event beds containing a co-genetic mud-clast-rich division

“…Considerable experimental work has explored the interaction of gravity currents and topography (Pantin and Leeder, 1987;Edwards et al, 1994;Kneller, 1997;Kneller and McCaffrey, 1999;Lamb et al, 2004Lamb et al, , 2006Toniolo et al, 2006a,b;Sequireos et al, 2009). Many have shown how disturbances, characterised by downstream changes in flow velocity and thickness, are generated locally where flows are obstructed by a confining obstacle (e.g., Pantin and Leeder, 1987;Edwards et al, 1994;Kneller, 1997;Lamb et al, 2004Lamb et al, , 2006Toniolo et al, 2006a,b;Sequireos et al, 2009).…”

Fill to spill stratigraphic evolution of a confined turbidite mini-basin succession, and its likely well bore expression: The Castagnola Fm, NW Italy

“…ripple drift lamination) in the upper sections in favour of repeated normal grading and wavy to hummocky-like laminations would suggest that pulsating or even oscillatory flow conditions (Tinterri 2011) lasted to the final stage of sedimentation, prior to deposition of the thick ponded mud cap (Pickering and Hiscott, 1985;Haughton 1994Haughton , 2000. The vertical sequence of sedimentary structures along with the average thickness of both the sandstone and the mud cap of type A beds suggest deposition from large volume turbidity currents ponded by the enclosing topography (Lamb et al, 2004;Toniolo et al, 2006a, b;Patacci et al, 2015).…”