generation are interpreted as originating from slope failures on the adjacent Venezuela, Guyana and Suriname continental margins. Simple numerical modelling has been enabled to determine turbidity current flow characteristics across the sediment waves to be estimated: internal Froude number = 0.7–1.1, flow thickness = 24–645 m, and flow velocity = 31–82 cm·s−1. Generally, on lower gradients beyond minor breaks of slope, flow thickness increases and flow velocity decreases, leading to an increase in wavelength and a decrease in height. Reversing buoyancy The behaviour of turbidity currents with buoyant fluid (such as currents with warm, fresh or brackish interstitial water entering the sea) has been investigated to find that the front speed decreases more rapidly than that of currents with the same density as the ambient fluid. These turbidity currents ultimately come to a halt as sedimentation results in a reversal of buoyancy, and the current lifts off, the point of lift-off remaining constant for a constant discharge. The lofted fluid carries fine sediment with it, forming a plume that rises to a level of neutral buoyancy (if in a stratified environment) or to the water surface, and spreads out. Sediment falling from the plume produces a widespread fall-out deposit, termed hemiturbidite. Experimental turbidity currents and field observations suggest that the shape of the lobe deposit formed by a lofting plume is narrower than for a similar non-lofting plume Prediction Prediction of erosion by turbidity currents, and of the distribution of turbidite deposits, such as their extent, thickness and grain size distribution, requires an understanding of the mechanisms of sediment transport and deposition, which in turn depends on the fluid dynamics of the currents. The extreme complexity of most turbidite systems and beds has promoted the development of quantitative models of turbidity current behaviour inferred solely from their deposits. Small-scale laboratory experiments therefore offer one of the best means of studying their dynamics. Mathematical models can also provide significant insights into current dynamics. In the long term, numerical techniques are most likely the best hope of understanding and predicting three-dimensional turbidity current processes and deposits. In most cases, there are more variables than governing equations, and the models rely upon simplifying assumptions in order to achieve a result. The accuracy of the individual models thus depends upon the validity and choice of the assumptions made. Experimental results provide a means of constraining some of these variables as well as providing a