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 National Science
Foundation Award #0549566 |
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SGER: Glacial Response to an Outburst Flood, Kennicott Glacier, Alaska |
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| Investigator(s): |
Robert Anderson (PI)
; Suzanne Anderson (Co-PI)
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| Sponsor: |
University of Colorado at Boulder, CO 80309 3034926221
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| Start Date/Expiration Date |
2005-09-15 to 2006-11-30 (amended 2005-09-12) |
| Awarded Amount to Date: |
$35,000 |
| Abstract: Models of landscape evolution in the face of repeated glaciation incorporate
assumptions about glacial sliding that are in need of field verification. Temperate glaciers slide
when water pressures are high. As primary subglacial erosion mechanisms are attributable to
sliding of the glacier over its bed, the spatial and temporal pattern of sliding, and of the
subglacial drainage network that control it, are important to understand. The proposed research
acts upon hypotheses generated in two recently completed NSF-supported grants in which 1) the
sliding field on the small Alaskan Bench glacier was carefully documented using continuous
differential GPS, reaching its maximum speed at times of highest water storage within the
glacier, and 2) the annual outburst flood of Hidden Creek Lake beside the much larger Kennicott
glacier was shown to greatly perturb the hydrologic system. The 400 m thickness of the
Kennicott Glacier allows much more rapid collapse of the subglacial drainage network than on
the 150 m thick Bench Glacier during times of low snowmelt input to the glacier surface. As the
snowmelt input increases again, the subglacial plumbing system must re-grow, during which
time it should re-pressurize, promoting another period of sliding. If this is the case, then glacial
thickness emerges as a primary control on the total annual sliding of a glacier, and therefore on
the ability of a glacier to erode the landscape. The proposed research takes advantage of the
accessibility and size of this Kennicott Glacier to investigate in detail the sliding history of this
large temperate glacier and its association with both the seasonally-evolving water storage and
pressure fields, and the inevitable annual Hidden Creek outburst flood.
In this pilot project, the following hypotheses will be tested, in the hope that the data
generated will serve as proof that the work is both tractable and productive of insight into the
system.
* Short-lived sliding increases will occur during ice dammed lake outbursts.
* Sliding anomalies at the Kennicott Glacier occur in association with synoptic variations in
melt inputs.
* Long, thick glaciers, like the Kennicott glacier, will experience both more total sliding than
thin glaciers, and multiple sliding events within a single melt season.
The data to be collected include time series of: glacier surface motion, using multiple GPS
receivers on the glacier run in differential continuous mode; water inputs by snowmelt and
outputs from the exit river to constrain evolution of the water balance; englacial water pressures
at several locations along the subglacial flood route that take advantage of side-glacier lakes and
moulins; water chemistry at the outlet stream. Taken together, this data will directly test an
existing model of linked glacial dynamics and subglacial network evolution.
Broader Impact. As the research will be accomplished near the Wrangell St Elias National
Park's primary entrance near McCarthy, the research on the Kennicott Glacier is ideally situated
to allow direct communication of both our scientific methods and results to the public. As in
prior work, public talks will be given to national park visitors in formal seminars. Activities will
be coordinated with the Wrangell Mountains Center, a private non-profit institute dedicated to
education and research, through their Alaska Wildlands Studies, a 7-week field course accredited
for college students through UC Santa Barbara. Guest lectures on principles and field techniques
of glaciology and glacial geology will be given, and opportunities for involvement of its these
students in the field work will be offered. The research will employ and train one Ph.D. student
from CU, and at two undergraduate students. |
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| NSF Org: |
EAR - Division of Earth Sciences |
| Award Number: |
0549566 |
| Award Instrument: |
Standard Grant |
| Program Manager: |
Michael A. Ellis
EAR Division of Earth Sciences
GEO Directorate for Geosciences
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| NSF Program(s): |
GEOMORPHOLOGY & LAND USE DYNAM |
| Field Application(s): |
Other nsf.applications NEC |
| Program Reference Code(s): |
SMALL GRANTS-EXPLORATORY RSRCH, 9237
UNASSIGNED, 0000 |
| Program Element Code(s): |
7458 |
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