--> Abstract: Submarine Channel Initiation and Evolution: an Experimental Approach; #90063 (2007)

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Submarine Channel Initiation and Evolution: an Experimental Approach

 

Kane, Ian1, Jeff Peakall1, William. D. McCaffrey1 (1) University of Leeds, Leeds, United Kingdom

 

Density flows in the subaqueous environment have different characteristics to their subaerial counterparts. In the subaqueous case, flows lack a free upper surface and there is a reduced density contrast between the flow and the ambient fluid. These factors alone suggest that the mechanics of the initiation, growth and abandonment of submarine slope channels may be very different from fluvial channels. Here we present a series of experiments designed to investigate the key factors controlling incipient channelisation. In particular, a key question is whether levee growth alone is enough to promote confinement, or whether contemporaneous channel thalweg incision is necessary? Experiments were performed in a flume tank 0.5 x 6 m in length, and 1.5 m deep. In the tank a sediment tray was placed on an adjustable slope table. At the updip end a continuous input of saline was introduced into the fresh water and allowed to spill onto a flat sediment surface. A lightweight polymer sediment analogue was used which was capable of being transported by the saline input current. Sustained flows revealed an autocyclic pattern of updip incision, down dip lobe building, lobe incision, in the form of a sinuous channel with levees, and updip canyon backfilling. The continuous input system allowed us to stop the system and take bathymetric profiles enabling detailed documentation of the evolution of the system. Results are presented and some comparisons to modern and subsurface systems are made; implications for hydrocarbon exploration are discussed.

 

AAPG Search and Discover Article #90063©2007 AAPG Annual Convention, Long Beach, California