HR: 16:00h
AN: H34C-01 [Abstracts]
TI: Autogenic Shoreline Responses to Fluvial Change
AU: * Kim, W
EM: kimx0826@umn.edu
AF: National Center for Earth-surface Dynamics, University of Minnesota, Minneapolis, MN 55414
United States
AU: * Kim, W
EM: kimx0826@umn.edu
AF: St. Anthony Falls Laboratory, University of Minnesota, Minneapolis, MN 55414
United States
AU: * Kim, W
EM: kimx0826@umn.edu
AF: Department of Geology and Geophysics, University of Minnesota, Minneapolis, MN 55455
United States
AU: Strong, N
EM: stro0068@umn.edu
AF: National Center for Earth-surface Dynamics, University of Minnesota, Minneapolis, MN 55414
United States
AU: Strong, N
EM: stro0068@umn.edu
AF: St. Anthony Falls Laboratory, University of Minnesota, Minneapolis, MN 55414
United States
AU: Strong, N
EM: stro0068@umn.edu
AF: Department of Geology and Geophysics, University of Minnesota, Minneapolis, MN 55455
United States
AU: Sheets, B A
EM: shee0076@umn.edu
AF: National Center for Earth-surface Dynamics, University of Minnesota, Minneapolis, MN 55414
United States
AU: Sheets, B A
EM: shee0076@umn.edu
AF: St. Anthony Falls Laboratory, University of Minnesota, Minneapolis, MN 55414
United States
AU: Sheets, B A
EM: shee0076@umn.edu
AF: Department of Geology and Geophysics, University of Minnesota, Minneapolis, MN 55455
United States
AU: Kelberer, M
EM: kelb0004@umn.edu
AF: National Center for Earth-surface Dynamics, University of Minnesota, Minneapolis, MN 55414
United States
AU: Kelberer, M
EM: kelb0004@umn.edu
AF: St. Anthony Falls Laboratory, University of Minnesota, Minneapolis, MN 55414
United States
AU: Kelberer, M
EM: kelb0004@umn.edu
AF: Department of Geology and Geophysics, University of Minnesota, Minneapolis, MN 55455
United States
AU: Martin, J
EM: martinj@umn.edu
AF: National Center for Earth-surface Dynamics, University of Minnesota, Minneapolis, MN 55414
United States
AU: Martin, J
EM: martinj@umn.edu
AF: St. Anthony Falls Laboratory, University of Minnesota, Minneapolis, MN 55414
United States
AU: Martin, J
EM: martinj@umn.edu
AF: Department of Geology and Geophysics, University of Minnesota, Minneapolis, MN 55455
United States
AU: Paola, C
EM: cpaola@umn.edu
AF: National Center for Earth-surface Dynamics, University of Minnesota, Minneapolis, MN 55414
United States
AU: Paola, C
EM: cpaola@umn.edu
AF: St. Anthony Falls Laboratory, University of Minnesota, Minneapolis, MN 55414
United States
AU: Paola, C
EM: cpaola@umn.edu
AF: Department of Geology and Geophysics, University of Minnesota, Minneapolis, MN 55455
United States
AU: Voller, V R
EM: volle001@umn.edu
AF: National Center for Earth-surface Dynamics, University of Minnesota, Minneapolis, MN 55414
United States
AU: Voller, V R
EM: volle001@umn.edu
AF: St. Anthony Falls Laboratory, University of Minnesota, Minneapolis, MN 55414
United States
AU: Voller, V R
EM: volle001@umn.edu
AF: Department of Civil Engineering, University of Minnesota, Minneapolis, MN 55455
United States
AU: Swenson, J B
EM: jswenso2@d.umn.edu
AF: Department of Geological Sciences and Large Lakes Observatory, University of Minnesota, Duluth, MN
55812
United States
AB:
We present experimental shoreline-migration data that show high-frequency autogenic variability superimposed on low-frequency
allogenic shoreline responses. The experiment, which was performed in the Experimental EarthScape (XES) facility at St.
Anthony Falls Laboratory, used (1) a linear-hinge type subsidence profile for which the subsidence rate was kept constant in
time, (2) a constant overall sediment supply, and (3) base-level variation on two time scales that were first applied
separately and then superimposed.
Autogenic signals in shoreline trajectory imprinted on the allogenic signatures are generally thought of as local "noise".
However, the variability in the experimental shoreline data persists even when the shoreline migration is averaged laterally.
The autogenic signal in the shoreline migration rate (i.e., a high-frequency variability of the rate) is strongest during
relative base-level rise and weakest during relative base-level fall. Base-level change, which is the only externally imposed
time-variable parameter in the experiment, can work either with or against the sediment transport regime and thus can
magnify or diminish autogenic processes. We use a 1-D geometric model to model the autogenic signals present in the
experiment. With the model, we investigate whether periodic changes in the fluvial slope could explain the effects of storage
and release of supplied sediment. By storing and releasing sediment, these slope changes can cause strong pulses of sediment
discharge to pass through the shoreline position, causing high-frequency change in the shoreline position against a
background of relatively long-term shoreline migration. A series of test results, using different magnitudes of the slope
change, different frequencies of sediment-release events, and different types of release events, suggests that the storage
and release model can explain much of the shoreline response.
UR: http://www.geo.umn.edu/orgs/seds/
DE: 4203 Analytical modeling
DE: 3210 Modeling
DE: 3230 Numerical solutions
DE: 1815 Erosion and sedimentation
DE: 1824 Geomorphology (1625)
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting