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Age of colluvium indicates accelerated late Wisconsinan hillslope erosion in the Upper Mississippi Valley

1997; Geological Society of America; Volume: 25; Issue: 3 Linguagem: Inglês

10.1130/0091-7613(1997)025 2.3.co;2

1943-2682

Joseph A. Mason, James C. Knox,

Cryospheric studies and observations

Research Article| March 01, 1997 Age of colluvium indicates accelerated late Wisconsinan hillslope erosion in the Upper Mississippi Valley Joseph A. Mason; Joseph A. Mason 1Department of Geography, Northern Illinois University, DeKalb, Illinois 60115 Search for other works by this author on: GSW Google Scholar James C. Knox James C. Knox 2Department of Geography, University of Wisconsin, 384 Science Hall, 550 North Park Street, Madison, Wisconsin 53706 Search for other works by this author on: GSW Google Scholar Author and Article Information Joseph A. Mason 1Department of Geography, Northern Illinois University, DeKalb, Illinois 60115 James C. Knox 2Department of Geography, University of Wisconsin, 384 Science Hall, 550 North Park Street, Madison, Wisconsin 53706 Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1997) 25 (3): 267–270. https://doi.org/10.1130/0091-7613(1997)025 2.3.CO;2 Article history First Online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Joseph A. Mason, James C. Knox; Age of colluvium indicates accelerated late Wisconsinan hillslope erosion in the Upper Mississippi Valley. Geology 1997;; 25 (3): 267–270. doi: https://doi.org/10.1130/0091-7613(1997)025 2.3.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 SocietyGeology Search Advanced Search Abstract Colluvium on foot slopes in parts of North America and Europe has been attributed to a major mass-wasting episode during the last glacial period. Stratigraphic evidence and 14C ages support this hypothesis for the northern part of the Upper Mississippi Valley. Colluvium in this region grades laterally into, or interfingers with, fluvial sediment beneath the late Wisconsinan Savanna terrace. Colluvial foot slopes are truncated by fluvial surfaces postdating the incision that created the Savanna terrace between 13 and 11 ka. Samples from within the colluvium have 14C ages between 18.6 and 12 ka. Ages of 28.9 and 20.3 ka have been obtained from beneath colluvium, and fluvial sediment inset into colluvial foot slopes has yielded ages between 12.5 and 9.8 ka. Widespread permafrost during the late Wisconsinan glacial maximum may explain the onset of accelerated mass wasting that produced the colluvium, although mass wasting apparently continued for some time during subsequent climatic warming. The results described here imply major, long-term, climatically driven fluctuations in sediment supply from hillslopes to the fluvial system in this region. This content is PDF only. Please click on the PDF icon to access. 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.