Self-channelization on laboratory subaqueous fans with a break in slope: implications for fan growth pattern

FERNANDEZ, ROCIO LUZ; CANTELLI, ALESSANDRO; PRIMEZ, CARLOS; PARKER, GARY

Santa Fe, Argentina

Congreso; River, Coastal and Estuarine Morphodynamics; 2009

Universidad Nacional del Litoral

The experiments describe a laboratory study of the evolution of channelized fans built by the passage of repeated individual turbidity current events. An abrupt break in the sloping bed over which the currents flowed is set-up for all experiments. This geometry allowed study of adjustments in deep-sea fan deposits associated with natural slope changes, as well as their effect on incipient fan channelization. Data analysis focused on: temporal and vertical/horizontal sequences of sedimentary structures; spatial trends in grain-size distribution within the channels, and velocity and concentration of the flows themselves. The development of the channel system involved both gradual shift and avulsion. The slope break played a very important role in governing channel aggradation and overall architecture over the entire deposit. A comparison with field analogs demonstrates that self-channelized fans can indeed be modeled, within limits, at laboratory scale.