Record Display for the EPA National Library Catalog


Main Title Contourites in Lake Superior.
Author Johnson, T. C. ; Carlson, T. W. ; Evans, J. E. ;
CORP Author Minnesota Univ., Minneapolis. Dept. of Geology and Geophysics.;Environmental Research Lab.-Duluth, MN.
Year Published 1980
Report Number EPA-R-805172; EPA-600/J-80/447;
Stock Number PB84-142447
Additional Subjects Sediments ; Water flow ; Lake Superior ; Geological sedimentation ; Seismic reflection method ; Profiles ; Sands ; Sampling ; Kewaenaw Peninsula ; Particle size ; Reprints ; Contourites
Library Call Number Additional Info Location Last
NTIS  PB84-142447 Some EPA libraries have a fiche copy filed under the call number shown. 07/26/2022
Collation 9p
Contour currents influence sedimentation in an area 15 km wide and 65 km long at the base of the slope off the Keweenaw Peninsula in Lake Superior, northwestern Michigan. Seismic-reflection profiles (3.5 kHz) from this area show distinct wavy reflectors in a scoured trough at a depth of 200 m at the base of the slope, hyperbolic echoes adjacent to the trough, and overlapping echos farther lakeward. These acoustic features are identical to those in marine environments where contourites are deposited. Box cores from the lakeward margin of this area contain what appeared to be contourites: irregular, thin sand layers with sharp upper and lower contacts, interbedded with sandy clay. This is the first report of contourites in a lacustrine environment.