An inverse problem to infer paleoflow conditions from turbidites

An inverse problem is here studied to infer paleoflow conditions from turbidites (i.e., from turbidity current deposits). Such a problem is constrained to outcrop data from the Laga Formation (Lower Messianian; central Apennines, Italy). Analytical solutions of layeraveraged governing equations for net depositional turbidity currents flowing over a flat bottom are found. These allow recovering conditions for current velocity, thickness, and sediment concentration at the start of the net deposition by using the analytic solution of the Exner equation for net-depositional turbidity currents. The Exner equation describes the along-current profile of a sedimentary bed deposited by a single depositional event. For lobe deposits of the Laga Formation we obtain values of 1.5 m/s for layer-averaged current velocities, 50-100 m for current thicknesses, and 0.5% for layer-averaged sediment volume concentrations. The duration time of these flows is also computed and gives rather short time span values varying from 1 to 15 h. All of these values are in good agreement with those reported in literature.