HR: 0800h
AN: PP11A-0208    [Abstracts]
TI: Evidence of Lacustrine Bedforms in Lake Champlain, Vermont
AU: Manley, P L
EM: manley@middlebury.edu
AF: Middlebury College, Geology Department, Middlebury, VT 05753, United States
AU: * Hayo, K
EM: khayo@usgs.gov
AF: Middlebury College, Geology Department, Middlebury, VT 05753, United States
AB: High resolution CHIRP seismic profiles reveal the presence of two large lacustrine sediment drifts (Drifts A and B) located in Lake Champlain's Juniper Deep. Both drifts are positive features composed of highly laminated sediments overlying trough-filling acoustically-transparent sediment. Both drifts are oriented approximately north-south and are parallel to a steep ridge along the eastern shore of the basin. Drift A, located at the bottom of a structural trough, is classified as a confined, elongate drift that transitions northward to become a system of mudwaves. Drift B is perched atop a structural high to the west of Drift A and is classified as a detached elongate drift. Bottom current depositional control was inferred from the orientations of the bedforms and modern lake circulation patterns. Sediment thicknesses and volume estimates were used to create isopach maps and 3-dimensional images detailing drift evolution. Sediment cores were taken at the crest and at the edges of the drifts. Drift source, deposition, and evolution will be discussed in the context of the regional history of the Lake Champlain Valley.
DE: 3045 Seafloor morphology, geology, and geophysics
DE: 4558 Sediment transport (1862)
DE: 4863 Sedimentation (1861)
DE: 4942 Limnology (0458, 1845, 4239)
DE: 9605 Neogene
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2007 Fall Meeting