How Evolution of Submarine Landscapes Differs from the Terrestrial System: The Role of Channelized and Unconfined Currents in Building the Continental Slope

David Mohrig, Department of Geological Sciences, Jackson School of Geosciences, The University of Texas at Austin

Abstract:

Acoustical imaging of the seafloor and subsurface now commonly provides high-resolution maps of submarine landscapes or seascapes dominated by submarine channels and their affiliated sedimentary deposits. Unfortunately, direct measurements of natural currents in these channels are still rare and measurements defining how currents interact with and modify channel forms are not yet available. This paucity of observations hampers the development of channel and seascape evolution models, and limits the ability to reconstruct past environmental states using deep-water stratigraphy. Interactions between turbidity currents and channels can be studied in the laboratory at reduced scales. Results from such experiments are presented here and highlight patterns of flow and sedimentation associated with 1) channel bends, 2) construction of channel-margin levees, and 3) unconfined currents. The experimental results are compared to properties of a modern slope system defined by an industry grade, 3D seismic volume. This study is intended to help guide interpretations of seascape evolution and through systematic comparison with better studied river systems will add to our general understanding of channelized planetary surfaces.