Self
Channelized Subaqueous Fans Emplaced by Turbidity Currents and Dilute Mudflows
Cantelli, Alessandro1, Carlos
Pirmez2,
The passage of turbidity currents over
submarine fans often results in intense channelization. The channels are
typically bounded by levees, and vary from mildly to strongly meandering. The process of self-channelization remains, however, somewhat
obscure. Experiments reported here demonstrate that self-channelization
of subaqueous fans by turbidity currents can be reproduced at laboratory scale.
The same experiments also illustrate self-channelization by dilute mudflows.
The resulting weakly sinuous channels can be predominantly depositional,
predominantly erosional or some combination of the two. The channels can
elongate to the length of the entire reach available for their formation. They
can show both gradual shift and avulsion. A necessary condition for the
formation of intricate channelization in the laboratory experiments appears to
be a turbidity current that is insufficient to cover the entire area of the fan
at any given time. Loose field analogs to the experimental channelized fans
(i.e. analogs that are imprecise but contain many similarities) can often be
found at the distal end of submarine fans. Two possible examples are cited, one
from the Pochnoi system,
AAPG Search and Discover Article #90063©2007 AAPG Annual Convention, Long Beach, California