Quantifying the
Morphology and Growth of Levees in a Submarine Tributary Channel System
Offshore
Straub, Kyle M.1, David Mohrig2
(1) Massachusetts Institute of Technology,
A network of submarine channels sharing
planform attributes similar to river systems is located on the present-day
continental slope offshore Brunei Darussalam. We mapped the seafloor and a
shallow regional surface beneath the network of interest using an industry-grade
3D seismic survey. The subsurface horizon defines the geometry of a scarp and
slide plane associated with a mass-failure event that reset the margin to an
unchannelized state. A map of deposit thickness was created by differencing the
seafloor and subsurface horizon and this thickness data is used to unravel the
growth of self-formed, leveed channels. With thickness and topographic data we
have determined sedimentation trends; particularly relative rates of levee and
overbank sedimentation as a function of lateral distance from the nearest
channel centerline. We also use the deposition map to quantify the relationship
between channel relief and levee taper. Levee steepness increases from 0.010
m/m to 0.050 m/m with a growth in channel depth from
AAPG Search and Discover Article #90063©2007 AAPG Annual Convention, Long Beach, California