The influence of a slope break on turbidite deposits

Abstract

Bypassing turbidity currents can travel downslope without depositing any of their suspended sediment load. Along the way, they may encounter a slope break (i.e. an abrupt decrease in slope angle) that initiates sediment deposition. Depending on the initiation point of deposition (the upslope pinch-out), these turbidite deposits in slope-break systems can form potential reservoirs for hydrocarbons. Here we investigate the distribution of turbidite deposits as a function of the geometry of slope-break systems in flume experiments. Shields-scaled turbidity currents were released into a flume tank containing an upper and a lower slope reach separated by a slope break. These slope-break experiments were generating both depositional and bypassing flows solely based on variation in steepness of the lower and upper slope. Results show that the depositional pattern in a slope-break system is controlled by the steepness of the upper and lower slope, rather than the angle of the slope break. The steepness of the upper slope controls the upslope pinch-out, while the lower slope controls the deposit thickness downstream of the slope break.