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Hyperpycnal plume-derived fans in the Santa Barbara Channel, California

June 1, 2013

Hyperpycnal gravity currents rapidly transport sediment across shore from rivers to the continental shelf and deep sea. Although these geophysical processes are important sediment dispersal mechanisms, few distinct geomorphic features on the continental shelf can be attributed to hyperpycnal flows. Here we provide evidence of large depositional features derived from hyperpycnal plumes on the continental shelf of the northern Santa Barbara Channel, California, from the combination of new sonar, lidar, and seismic reflection data. These data reveal lobate fans directly offshore of the mouths of several watersheds known to produce hyperpycnal concentrations of suspended sediment. The fans occur on an upwardly concave section of the shelf where slopes decrease from 0.04 to 0.01, and the location of these fans is consistent with wave- and auto-suspending sediment gravity current theories. Thus, we provide the first documentation that the morphology of sediment deposits on the continental shelf can be dictated by river-generated hyperpycnal flows.

Publication Year 2013
Title Hyperpycnal plume-derived fans in the Santa Barbara Channel, California
DOI 10.1002/grl.50488
Authors Jonathan A. Warrick, Alexander R. Simms, Andy Ritchie, Elisabeth Steel, Pete Dartnell, James E. Conrad, David P. Finlayson
Publication Type Article
Publication Subtype Journal Article
Series Title Geophysical Research Letters
Index ID 70100645
Record Source USGS Publications Warehouse
USGS Organization Pacific Coastal and Marine Science Center