Navigation auf zora.uzh.ch

Search ZORA

ZORA (Zurich Open Repository and Archive)

DDOS: due to massive botnet requests against our ‘Advanced Search’ we have restricted access to UZH (local and VPN). Thank you for your understanding.

A numerical study of glacier advance over deforming till

Leysinger Vieli, Gwendolyn; Gudmundsson, G Hilmar (2010). A numerical study of glacier advance over deforming till. The Cryosphere, 4(3):359-372.

Abstract

The advance of a glacier over a deforming sediment layer is analysed numerically. We treat this problem as a contact problem involving two slowly-deforming viscous bodies. The surface evolution of the two bodies, and of the contact interface between them, is followed through time. Using various different non-linear till rheologies, we show how the mode of advance depends on the relative effective viscosities of ice and till. Three modes of advances are observed: (1) overriding, where the glacier advances through ice deformation only and without deforming the sediment; (2) plug-flow, where the sediment is strongly deformed, the ice moves forward as a block and a bulge is built in front of the glacier; and (3) mixed-flow, where the glacier advances through both ice and sediment deformation. For the cases of both overriding and mixed-flow, an inverse depth-age relationship within the ice is obtained. A series of model experiments show the contrast in effective viscosity between ice and till to be the single most important model parameter defining the mode of advance and the resulting thickness distribution of the till. Our model experiments indicate that the thickness of the deforming till layer is greatest close to the glacier front. Measurements of till thickness taken in such locations may not be representative of deforming till thickness elsewhere. Given sufficiently large contrast in effective viscosity between ice and till, a sediment bulge is formed in front of the glacier. During glacier advance, the bulge quickly reaches a steady state form strongly resembling single-crested push moraines. Inspection of particle paths within the sediment bulge, shows that particles within the till travel at a different speed from the bulge itself, and the push moraine to advance as a form-conserving non-linear wave.

Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:07 Faculty of Science > Institute of Geography
Dewey Decimal Classification:910 Geography & travel
Scopus Subject Areas:Physical Sciences > Water Science and Technology
Physical Sciences > Earth-Surface Processes
Language:English
Date:2010
Deposited On:14 Feb 2017 13:21
Last Modified:15 May 2025 03:43
Publisher:Copernicus Publications
ISSN:1994-0416
OA Status:Gold
Free access at:Publisher DOI. An embargo period may apply.
Publisher DOI:https://doi.org/10.5194/tc-4-359-2010
Download PDF  'A numerical study of glacier advance over deforming till'.
Preview
  • Content: Published Version
  • Language: English
  • Licence: Creative Commons: Attribution 3.0 Unported (CC BY 3.0)

Metadata Export

Statistics

Citations

Dimensions.ai Metrics
11 citations in Web of Science®
15 citations in Scopus®
Google Scholar™

Altmetrics

Downloads

57 downloads since deposited on 14 Feb 2017
1 download since 12 months
Detailed statistics

Authors, Affiliations, Collaborations

Similar Publications