Grain-size distribution in deforming subglacial tills: Role of grain fracture

Abstract

Research Article| January 01, 1995 Grain-size distribution in deforming subglacial tills: Role of grain fracture Roger LeB. Hooke; Roger LeB. Hooke 1Department of Geology and Geophysics, University of Minnesota, Minneapolis, Minnesota 55455 Search for other works by this author on: GSW Google Scholar Neal R. Iverson Neal R. Iverson 1Department of Geology and Geophysics, University of Minnesota, Minneapolis, Minnesota 55455 Search for other works by this author on: GSW Google Scholar Geology (1995) 23 (1): 57–60. https://doi.org/10.1130/0091-7613(1995)023<0057:GSDIDS>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 MailTo Tools Icon Tools Get Permissions Search Site Citation Roger LeB. Hooke, Neal R. Iverson; Grain-size distribution in deforming subglacial tills: Role of grain fracture. Geology 1995;; 23 (1): 57–60. doi: https://doi.org/10.1130/0091-7613(1995)023<0057:GSDIDS>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 New ways of looking at grain-size distributions may yield insights into sedimentary processes or environments. For example, during shearing of a granular material, alignments of grains, or bridges, develop with orientations such that compressive forces parallel to these alignments support most of the applied shear stress. If deformation is due to failure of such bridges by fracture, rather than by, say, dilation, the grain-size distribution will tend toward one that provides the maximum support for the grains. This size distribution is fractal and has a fractal dimension of 2.6. We analyzed the grain-size distribution of three deforming tills collected from beneath modern glaciers. The size distributions are fractal, and the mean fractal dimension is ∼2.9, suggesting an excess of fines. For comparison, grain-size distributions of samples from some other common sedimentary environments were also analyzed. Samples of dune sand and of glacial outwash were not fractal, but a debris-flow sample was, and had a fractal dimension of 2.8. 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.