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Microphysiography and Possible Iceberg Grooves on the Floor of Western Lake Superior
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1973
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GlacierEngineeringGeomorphologyPolar EnvironmentsGlacial ProcessEarth ScienceGeophysicsIce-water SystemMarine GeologyGsa Bulletin 1973America Gsa BulletinGeographyPossible IcebergWestern Lake SuperiorGeologyCryosphereTectonicsStructural GeologyLake SuperiorEarth SciencesIce-structure Interaction
Research Article| April 01, 1973 Microphysiography and Possible Iceberg Grooves on the Floor of Western Lake Superior J. M. BERKSON; J. M. BERKSON 1Geophysical and Polar Research Center, Department of Geology and Geophysics, University of Wisconsin—Madison, 6118 University Avenue, Middleton, Wisconsin 53562 Search for other works by this author on: GSW Google Scholar C. S. CLAY C. S. CLAY 1Geophysical and Polar Research Center, Department of Geology and Geophysics, University of Wisconsin—Madison, 6118 University Avenue, Middleton, Wisconsin 53562 Search for other works by this author on: GSW Google Scholar Author and Article Information J. M. BERKSON 1Geophysical and Polar Research Center, Department of Geology and Geophysics, University of Wisconsin—Madison, 6118 University Avenue, Middleton, Wisconsin 53562 C. S. CLAY 1Geophysical and Polar Research Center, Department of Geology and Geophysics, University of Wisconsin—Madison, 6118 University Avenue, Middleton, Wisconsin 53562 Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (1973) 84 (4): 1315–1328. https://doi.org/10.1130/0016-7606(1973)84<1315:MAPIGO>2.0.CO;2 Article history First Online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation J. M. BERKSON, C. S. CLAY; Microphysiography and Possible Iceberg Grooves on the Floor of Western Lake Superior. GSA Bulletin 1973;; 84 (4): 1315–1328. doi: https://doi.org/10.1130/0016-7606(1973)84<1315:MAPIGO>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract The floor of Lake Superior northwest of the Keweenaw Peninsula has three zones of small-scale relief based on echogram character. The zones are roughly depth dependent. Zone A, located between the shore to about a 54-m depth, is generally smooth on the echogram and consists mainly of sand and boulder gravel deposits. Zone B, between about 54 and 165 m, has microroughness features with a 2- to 5-m relief and a 90- to 300-m spacing; the bottom consists of glacial till and lacustrine clay. Zone C, below depths of about 165 m, has narrow troughs with depths to 12 m and separation of 60 to 600 m; the bottom consists of lacustrine clay. The microrelief of Zone B consists of an intersecting network of grooves having widths of 5 to 75 m and lengths of as much as 1,950 m. Regular parallel features 15 to 30 m apart are also found in scattered areas of Zone B and the deepest parts of Zone A. Sand and boulder gravel deposits of Zone A may be beach and dune material of lower glacial-lake stages, and the border with Zone B may mark the lowest shoreline during the sequence of glacial lakes in the Superior basin. The grooves of Zone B were probably formed by scouring by icebergs during an earlier lake stage. Relief in Zone C probably was formed by a lacustrine process. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.