UMD News Releases

Scanner is One of Only Six in the World
and Two in the United States

The University of Minnesota Duluth (UMD) Large Lakes Observatory (LLO) has acquired a new age, high-tech ITRAX x-ray fluorescence core scanner which will permit LLO researchers to study records of past changes in climate as preserved in the sediments of lakes. The instrument will be used to make rapid measurements of the chemical composition of the sediment cores of lakes enabling the scientists to discover how the earth's climate has altered in the past in response to changes such as solar activity, volcanic activity and atmospheric composition (green house gases).

The revolutionary device, designed and manufactured by Cox Analytical Systems of Gotenburg, Sweden is valued at approximately $400,000. It is the second of its kind installed in the United States, and the sixth in the world. The other in the United States is located at the Woods Hole Oceanographic Institution in Woods Hole, Massachusetts.

The ITRAX is capable of making measurements at a resolution of 0.2 mm, which corresponds to sediments deposited over a period of a few months in typical lake sediment. Such high resolution study would be impossible by conventional techniques, which require physically subsampling sediments. Analyses using the XRF core scanner are far more rapid-perhaps 100 times faster-than those previously employed, and are essentially non-destructive to core samples.

The Woods Hole on-line magazine, "Oceanus", describes it this way:
The XRF reveals intimate details of the composition of ancient mud and rock, which can contain a variety of clues about past climate and environmental conditions on Earth. The instrument simultaneously captures digital photographs and X-ray images of samples, while detecting measurable amounts of any of 80 chemical elements from aluminum (atomic number 11) to uranium (atomic number 92) without breaking the surface of the core. It gathers all of this data in a matter of hours.

Traditionally, scientists (or more likely, their students) spend months to years sifting through mud and sediment cores to measure carbon, trace metals, pollen, microscopic shells, and other materials that accumulate over time in coastal marshes and dunes or on the seafloor. By analyzing the sequential layers of this preserved detritus, scientists can reconstruct past changes in ocean temperatures, rainfall, wind, and vegetation patterns. They can determine when droughts, hurricanes, or blooms of marine plankton occurred.

To study core samples, scientists must cut them down the middle and meticulously dissect them. It is a time and labor-intensive process that gradually destroys unique--and not easily replaceable--cores. Sometimes cores must be shipped to other locations if scientists need an X-ray view to see layers undetected by the eye.

Current projects at UMD's Large Lake Observatory include studies of records recovered from Lake Malawi in East Africa and lakes in Central Asia, as well as the North American Great Lakes. The LLO core scanner will be available to the wider research community for collaborative projects.

Funding for the ITRAX x-ray florescent scanner was provided by the National Science Foundation's Major Research Instrumentation Program, the UMD College of Science and Engineering, and the UMD Large Lakes Observatory.