Device to Detect Climate Changes
By Steve Kuchera
Duluth News Tribune
Published June 28, 2006
The University of Minnesota Duluth has a new tool for
exploring the past.
UMD's Large Lakes Observatory recently acquired an X-ray
fluorescence core scanner to analyze lake bottom sediments,
which contain clues to past climates and climate changes.
The $400,000 scanner is one of only six in the world
and two in the United States -- the other at Woods Hole
Oceanographic Institution in Massachusetts.
The Large Lakes Observatory received its device earlier
"It's been running basically 24-7 since," said
geological sciences professor Erik T. Brown.
The scanner is basically a large box, about 17 feet long
and 30 inches high. In the middle, the X-ray device itself
stands about 6 feet tall. Core samples up to 6 feet long
are fed in one end, and, after passing beneath the X-ray
tower, emerge from the other end.
As the sample passes through the scanner, the instrument
can photograph it, X-ray it and determine its chemical
Careful examination of the chemicals and fossils in sediment
can reveal a record of past climates. A better understanding
of past climates may unveil cycles that will allow researchers
to better predict future changes.
Two main advantages of the X-ray device are the speed
and detail at which it examines samples.
The device can make measurements at a resolution of 0.008
inch -- the thickness of the layer of sediments deposited
over just a few months in a typical lake.
"Physically sampling material by hand at that kind
of resolution is impossible," Brown said.
And X-ray testing doesn't destroy the samples, as physical
The Large Lake Observatory is using the X-ray sampler
to study cores from the Great Lakes, lakes in Central
Asia and Lake Malawi in East Africa.
The observatory was part of a team that collected 2,044
feet of core samples from the bottom of Lake Malawi last
year. The samples contain a record of climates dating
back 1.5 million years -- 15 times older than previous
By chance, the Large Lakes Observatory received its X-ray
sampler the same month it's hosting the 10th International
More than 250 scientists from around the world are in
Duluth this week for the symposium, which runs through
Thursday at the Duluth Entertainment Convention Center.
Paleolimnology is the scientific study of the history
of lakes. The focus of the symposium is the impact of
humans on the Earth's ecosystems.
Officials with the observatory are using the symposium
as an opportunity to tell others about the X-ray scanner
in hopes of forming research partnerships.
"This thing produces so much data it's overwhelming,"
Brown said. "We want it used as much as possible,
and the way to do that is to have a lot of collaborations
with other people."