title: Effects of basal debris on glacier flow.
abstract: Glacier movement is resisted partially by debris, either within glaciers or under glaciers in water-saturated layers. In experiments beneath a thick, sliding glacier, ice containing 2 to 11% debris exerted shear traction of 60 to 200 kilopascals on a smooth rock bed, comparable to the total shear traction beneath glaciers and contrary to the usual assumption that debris-bed friction is negligible. Imposed pore-water pressure that was 60 to 100% of the normal stress in a subglacial debris layer reduced shear traction on the debris sufficiently to halt its deformation and cause slip of ice over the debris. Slip resistance was thus less than debris shearing resistance.
authors.affiliation: Department of Geological and Atmospheric Sciences, Iowa State University, Ames, IA 50011, USA. niverson@iastate.edu
authors.forename: Neal R
authors.initials: NR
authors.lastname: Iverson
authors.forename: Denis
authors.initials: D
authors.lastname: Cohen
authors.forename: Thomas S
authors.initials: TS
authors.lastname: Hooyer
authors.forename: Urs H
authors.initials: UH
authors.lastname: Fischer
authors.forename: Miriam
authors.initials: M
authors.lastname: Jackson
authors.forename: Peter L
authors.initials: PL
authors.lastname: Moore
authors.forename: Gaute
authors.initials: G
authors.lastname: Lappegard
authors.forename: Jack
authors.initials: J
authors.lastname: Kohler