Surface boulder concentrations of the Late Wisconsinan Rainy lobe, Minnesota, USA

Surface boulder concentrations on the surface of till sheets are ubiquitous features of the Late Wisconsinan Rainy lobe. They occur irrespective of topography or position on the landscape and are commonly found littering the surface of uncultivated pastures and wooded areas within the Wadena and Brainerd drumlin fields of central Minnesota and the Toimi drumlin field and the Rögen moraine of northeastern Minnesota. Previous work in these locations noted the occurrence of surface boulders but dismissed them as an erosional lag or resulting from periglacial processes. Characterizations of boulder lithologies, the composition and texture of the underlying till, and mean transport length suggest that this is not the case, and that surface boulder concentrations are primary features of till deposition. We present models for surface boulder deposition in both lodgement till and deforming bed regimes.

Author dc:creator

• Berthold, Angela Jeannine

• Boulder lag
• Boulder pavements
• Deforming bed
• Rainy lobe
• Surface boulders
• Transport length
• Geological sciences
• Plan As (thesis-based master's degrees)
• Department of Earth and Environmental Sciences
• Swenson College of Science and Engineering
• University of Minnesota Duluth
• Master of Science
• Master of Science in Geological Sciences

Language dc:language.iso

en

Handle dc:identifier.uri

https://hdl.handle.net/11299/170659

OAI identifier oai:identifier

oai:conservancy.umn.edu:11299/170659