HR: 0800h
AN: C41A-0040    [Abstracts]
TI: Investigation Into the Origin of Submarine Channelized Deposits Found on the Continental Shelf of Southern Alaska
AU: * Elmore, R
EM: crelmore@mail.utexas.edu
AF: University of Texas at Austin Department of Geological Sciences, Jackson School of Geosciences, 1 University Station C1100, Austin, TX 78712, United States
AU: * Elmore, R
EM: crelmore@mail.utexas.edu
AF: University of Texas at Austin Institute for Geophysics, 10100 Burnet Rd. Bldg. 196, Austin, TX 78758-4445, United States
AU: Gulick, S P
EM: sean@ig.utexas.edu
AF: University of Texas at Austin Institute for Geophysics, 10100 Burnet Rd. Bldg. 196, Austin, TX 78758-4445, United States
AU: Mohrig, D
EM: mohrig@mail.utexas.edu
AF: University of Texas at Austin Department of Geological Sciences, Jackson School of Geosciences, 1 University Station C1100, Austin, TX 78712, United States
AU: Willems, B A
EM: bawill3@gmail.com
AF: Department of Geology and Environmental Sciences Northern Illinois University, Davis Hall 312, Normal Rd., DeKalb, IL 60115, United States
AU: Powell, R D
EM: ross@geol.niu.edu
AF: Department of Geology and Environmental Sciences Northern Illinois University, Davis Hall 312, Normal Rd., DeKalb, IL 60115, United States
AU: Jaeger, J M
EM: jaeger@geology.ufl.edu
AF: University of Florida Department of Geological Sciences, 241 Williamson Hall P.O. Box 112120, Gainesville, FL 32611, United States
AB: The interaction between tectonic exhumation and climatic events along the southern coast of Alaska provides a unique setting in which the interplay of these significant processes can be evaluated. High precipitation rates and topographic relief in conjunction with the cool, temperate nature of the Alaskan coast produce large-scale glaciation across the margin. As such, glacial erosion processes control much of the sediment yield to the continental shelf during advance and retreat stages that have persisted throughout the last ~2.5 myr. Numerous large-scale channel structures preserved within continental shelf sediments may serve as markers of glacial advances or retreats and may illustrate significant glacial-marine processes. We have undertaken an integrated study into the origin of these structures using 1979 industry seismic data provided courtesy of the USGS and NSF-funded, high-resolution seismic data. Channel geometries range in scale from 513 m wide by 60 m deep, up to 4700 m wide and 355 m deep. Differentiation of the channels from the surrounding sediment is possible due to the hummocky, unstratified seismic character of the deposits filling the channels. Bright reflectors in the seismic data, likely representing glacial retreat surfaces, tend to terminate at channel margins. Packages of stacked or overlapping channels are common, suggesting reactivation of the channel surfaces. Although the exact nature of channel formation is still ambiguous, their considerable size and abundance speaks to their potentially significant role in piecing together a geologic history of the margin. Preliminary results suggest that glacially driven physical processes during advance and/or retreat are responsible for their formation. Interpretation of the seismic data will provide a means to determine if the channels are related to sub-ice movement of water or ice proximal erosional processes. Concurrently, with correct interpretation of channels and major erosional horizons, age associations amongst the channels are possible. In using the channels and major erosional horizons as markers in time and space, our goal will ultimately be to gain a better understanding of the degree of influence that the numerous glacial cycles, relative to one another, have had on the delivery and accumulation of sediment along the margin.
DE: 0720 Glaciers
DE: 1861 Sedimentation (4863)
DE: 3025 Marine seismics (0935, 7294)
DE: 8104 Continental margins: convergent
DE: 8177 Tectonics and climatic interactions
SC: Cryosphere [C]
MN: 2007 Fall Meeting