Taking a Quick Scan

We can learn a lot by going back in time, but scientific methods for looking at the past can take, well, a lot of time. Ancient ash, pollen and chemical changes in ocean sediment cores give us glimpses into a long-gone world, but they also provide clues to our future. And yet, analyzing these cores takes weeks, if not months — until now.


June 29, 2015

Anders Carlson, associate professor in the College of Earth, Ocean, and Atmospheric Sciences at Oregon State University. (Photo: Abby Metzger)
Anders Carlson, associate professor in the College of Earth, Ocean, and Atmospheric Sciences at Oregon State University. (Photo: Abby Metzger)

We can learn a lot by going back in time, but scientific methods for looking at the past can take, well, a lot of time. Ancient ash, pollen and chemical changes in ocean sediment cores give us glimpses into a long-gone world, but they also provide clues to our future. And yet, analyzing these cores takes weeks, if not months — until now.

Analysis of a sediment core reveals patterns of iron (red) and potassium (blue) concentrations over time. (Photo courtesy of Anders Carlson)
Analysis of a sediment core reveals patterns of iron (red) and potassium (blue) concentrations over time. (Photo courtesy of Anders Carlson)

With support from the National Science Foundation, scientists at Oregon State University have installed a new instrument known as an x-ray fluorescence scanner, which promises to cut that analysis time to hours. The instrument will be one of only two in the western United States, adding to Oregon State’s growing capacity for pioneering paleoclimate research. The scanner can rapidly process up to 1.5-meter lengths of sediment core and measure concentrations of a suite of elements from aluminum to uranium.

Oregon State maintains one of the nation’s largest archives of sediment cores — columns of soil extracted from the Earth. Scientists have long used the cores to reconstruct past climate scenarios.

“It would take weeks or months to do this in a normal lab setting,” says Anders Carlson, an associate professor in the College of Earth, Ocean, and Atmospheric Sciences and principal investigator on the NSF grant. “This instrument does it much faster, and at a higher resolution.”

The scanner can detect changes in the concentration of elements over as little as 0.1 millimeter in length, or 75 times narrower than an average human hair. A complete scan produces a colorful, high-resolution read-out of the core’s composition — a kind of elemental alphabet whose letters tell a storied tale of Earth’s history. Scientists can synch changes in elemental compositions to major events or hazards. Ice sheets, for example, slough off and deposit sediments that contain a unique elemental signature. This signature can help scientists pinpoint the collapse of ancient ice sheets and determine the conditions that may spell similar events in the future.

The instrument’s versatility and power mean Carlson and colleagues can look at both short- and long-term changes, whether on a pre-industrial or paleo timescale. More broadly, the instrument can provide data to illuminate land-use changes, seismic records or even past human activities. The collaborative effort to bring the instrument to Oregon State involved colleges as diverse as Liberal Arts and Engineering. This partnership demonstrates the scanner’s far-reaching capabilities, says Carlson.

“The support of other colleges shows a wide interest across campus in looking at environmental and climactic change and how these changes impact the Earth, both in terms of past interactions and modern-day humanity,” he adds.

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