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- July 28, 2006
Geology Department receives NSF funding to develop laboratory device
to study subglacial processes
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Three weeks out of a year, Neal Iverson spends his days (and nights) living
beneath a glacier 700 feet thick. The temperature is a constant 35 degrees
Fahrenheit. Not your ideal working conditions.
The Iowa State University professor of geological and atmospheric sciences'
research on glaciers has taken him all over the world, including Norway's
Svartisen Glaciological Observatory, a tunnel cut underneath the Svartisen
Ice Cap.
There he conducts field experiments aimed at better understanding glacier
flow, erosion and sedimentation.
But now thanks to a National Science Foundation (NSF) grant Iverson will
be able to conduct his research much closer to his Department of Geological
and Atmospheric Sciences office in Science I. In fact just down the hall.
The NSF has awarded Iverson a $530,000 grant for the development of a laboratory
"ring-shear" device for the study of subglacial processes. The device will
be designed and built by Iverson and mechanical engineers in the Department
of Energy's Ames Laboratory at Iowa State.
Iverson said the one-of-a-kind device will allow conditions at the bottom
of a glacier to be replicated and studied far better than in past experiments.
"We hope to study processes that occur at glacier beds where the ice
meets rock or sediment," he said. "These processes, like glacier
sliding and deformation of basal sediments, help determine how fast glaciers
move and how they've built the landscape, including those of Iowa."
An international expert in glaciers, Iverson says this device will be the
first of its kind in the world. While field research has provided vast information
on glaciers, the Iowa State professor says the new device can help answer
questions about the speed of glacier sliding, mechanisms of glacial erosion
and sedimentation and the meaning of structures preserved in the geologic
record of glaciation.
"There is only so much you can learn looking at sediments in Iowa,
inserting instruments into bore holes in glaciers or even doing the subglacal
work we do in Norway," Iverson said. "Geologists have been doing
laboratory flume experiments for about 100 years to study the flow and sediment
dynamics of rivers. An analogous approach to the study of glaciers is long
overdue."
Features of the ring-shear device will include the use of a rock or sediment
bed, unlimited sliding displacement, control of either stresses or sliding
rates, control of basal water pressure, temperature control to 0.01 C, and
continuous observation of sliding, sediment movement and flow separation
between ice and the bed. The device will be housed and operated in an existing
cold room in the Department of Geological and Atmospheric Sciences in Science
I.
Iverson said attempting to simulate conditions will be difficult. One of
the biggest challenges will be keeping a large volume of ice exactly at
its melting temperature – true of ice at the bases of many of the world's
glaciers – without melting the ice too fast.
The NSF has funded Iverson and his team for three years. The initial timeline
is to design and build the machine in the first two years and then begin
tests in year three. Other glacier experts have already contacted Iverson
about conducting experiments including researchers at ETH-Zurich, the University
of Aberystwyth- Wales, the University of California-Berkeley and the University
of California-Santa Cruz.
Iverson says he expects to use the new device for the rest of his academic
career.
"We'll have a piece of equipment that can be used to study a broad
range of processes that happen at the bottom of a glacier and that we've
only been able to speculate on in the past," he said. "This will
provide hypothesis-testing opportunities we've only dreamed about."
Neal Iverson
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