Spatial distribution of glacial erosion rates in the St. Elias range, Alaska, inferred from a realistic model of glacier dynamics
Glaciers have been principal erosional agents in many orogens throughout much of the recent geological past. A modern example is the St. Elias Mountains in southeastern Alaska; it is a highly convergent, complex orogen, which has been glaciated for much of its history. We examine the Seward-Malaspin...
Main Authors: | , , , , |
---|---|
Format: | Article in Journal/Newspaper |
Language: | unknown |
Published: |
eScholarship, University of California
2012
|
Subjects: | |
Online Access: | https://escholarship.org/uc/item/4338898h |
id |
ftcdlib:oai:escholarship.org/ark:/13030/qt4338898h |
---|---|
record_format |
openpolar |
spelling |
ftcdlib:oai:escholarship.org/ark:/13030/qt4338898h 2023-05-15T16:20:26+02:00 Spatial distribution of glacial erosion rates in the St. Elias range, Alaska, inferred from a realistic model of glacier dynamics Headley, R Hallet, B Roe, G Waddington, ED Rignot, E n/a - n/a 2012-09-01 application/pdf https://escholarship.org/uc/item/4338898h unknown eScholarship, University of California qt4338898h https://escholarship.org/uc/item/4338898h CC-BY CC-BY Journal of Geophysical Research: Earth Surface, vol 117, iss 3 Earth Sciences article 2012 ftcdlib 2021-09-13T17:11:45Z Glaciers have been principal erosional agents in many orogens throughout much of the recent geological past. A modern example is the St. Elias Mountains in southeastern Alaska; it is a highly convergent, complex orogen, which has been glaciated for much of its history. We examine the Seward-Malaspina Glacier system, which comprises two of the largest temperate glaciers in the world. We focus on the pattern of erosion within its narrow passage through the St. Elias Mountains, the Seward Throat. Measured glacier surface velocities and elevations provide constraints for a full-stress numerical flowband model that enables us to quantitatively determine the glacier thickness profile, which is not easily measured on temperate glaciers, and the basal characteristics relevant for erosion. These characteristics at the bed, namely the water pressure, normal and shear stresses, and sliding velocity, are then used to infer the spatial variation in erosion rates using several commonly invoked erosion laws. The calculations show that the geometry of the glacier basin exerts a far stronger control on the spatial variation of erosion rates than does the equilibrium line altitude, which is often assumed to be important in studies of glaciated orogens. The model provides a quantitative basis for understanding why erosion rates are highest around the Seward Throat, which is generally consistent with local and large-scale geological observations and thermochronologic evidence. Moreover, model results suggest how glacier characteristics could be used to infer zones of active or recent uplift in ice-mantled orogens. © 2012. American Geophysical Union. All Rights Reserved. Article in Journal/Newspaper glacier glaciers Alaska University of California: eScholarship Narrow Passage ENVELOPE(-79.266,-79.266,55.684,55.684) |
institution |
Open Polar |
collection |
University of California: eScholarship |
op_collection_id |
ftcdlib |
language |
unknown |
topic |
Earth Sciences |
spellingShingle |
Earth Sciences Headley, R Hallet, B Roe, G Waddington, ED Rignot, E Spatial distribution of glacial erosion rates in the St. Elias range, Alaska, inferred from a realistic model of glacier dynamics |
topic_facet |
Earth Sciences |
description |
Glaciers have been principal erosional agents in many orogens throughout much of the recent geological past. A modern example is the St. Elias Mountains in southeastern Alaska; it is a highly convergent, complex orogen, which has been glaciated for much of its history. We examine the Seward-Malaspina Glacier system, which comprises two of the largest temperate glaciers in the world. We focus on the pattern of erosion within its narrow passage through the St. Elias Mountains, the Seward Throat. Measured glacier surface velocities and elevations provide constraints for a full-stress numerical flowband model that enables us to quantitatively determine the glacier thickness profile, which is not easily measured on temperate glaciers, and the basal characteristics relevant for erosion. These characteristics at the bed, namely the water pressure, normal and shear stresses, and sliding velocity, are then used to infer the spatial variation in erosion rates using several commonly invoked erosion laws. The calculations show that the geometry of the glacier basin exerts a far stronger control on the spatial variation of erosion rates than does the equilibrium line altitude, which is often assumed to be important in studies of glaciated orogens. The model provides a quantitative basis for understanding why erosion rates are highest around the Seward Throat, which is generally consistent with local and large-scale geological observations and thermochronologic evidence. Moreover, model results suggest how glacier characteristics could be used to infer zones of active or recent uplift in ice-mantled orogens. © 2012. American Geophysical Union. All Rights Reserved. |
format |
Article in Journal/Newspaper |
author |
Headley, R Hallet, B Roe, G Waddington, ED Rignot, E |
author_facet |
Headley, R Hallet, B Roe, G Waddington, ED Rignot, E |
author_sort |
Headley, R |
title |
Spatial distribution of glacial erosion rates in the St. Elias range, Alaska, inferred from a realistic model of glacier dynamics |
title_short |
Spatial distribution of glacial erosion rates in the St. Elias range, Alaska, inferred from a realistic model of glacier dynamics |
title_full |
Spatial distribution of glacial erosion rates in the St. Elias range, Alaska, inferred from a realistic model of glacier dynamics |
title_fullStr |
Spatial distribution of glacial erosion rates in the St. Elias range, Alaska, inferred from a realistic model of glacier dynamics |
title_full_unstemmed |
Spatial distribution of glacial erosion rates in the St. Elias range, Alaska, inferred from a realistic model of glacier dynamics |
title_sort |
spatial distribution of glacial erosion rates in the st. elias range, alaska, inferred from a realistic model of glacier dynamics |
publisher |
eScholarship, University of California |
publishDate |
2012 |
url |
https://escholarship.org/uc/item/4338898h |
op_coverage |
n/a - n/a |
long_lat |
ENVELOPE(-79.266,-79.266,55.684,55.684) |
geographic |
Narrow Passage |
geographic_facet |
Narrow Passage |
genre |
glacier glaciers Alaska |
genre_facet |
glacier glaciers Alaska |
op_source |
Journal of Geophysical Research: Earth Surface, vol 117, iss 3 |
op_relation |
qt4338898h https://escholarship.org/uc/item/4338898h |
op_rights |
CC-BY |
op_rightsnorm |
CC-BY |
_version_ |
1766008345296109568 |