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

Abstract

Small intraslope basins (~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.