A team of scientists has developed a new method of radiometric krypton dating that accurately determines the age of Antarctic ice as far back as 1.5 million years.
Researchers gathered samples from the Taylor Glacier in Antarctica for the experiment. Analysts used a few pieces of 300-kilogram chunks of ice, then melted them to produce air bubbles. The air bubbles were later stored in flanks, while the krypton from the air bubbles were isolated and sent to Argonne National Laboratory just outside Chicago for krypton-81 dating.
"The oldest ice found in drilled cores is around 800,000 years old, and with this new technique we think we can look in other regions and successfully date polar ice back as far as 1.5 million years," postdoctoral researcher at Oregon State University Christo Buizert said in a press release. "That is very exciting because a lot of interesting things happened with the earth's climate prior to 800,000 years ago that we currently cannot study in the ice core record."
The research team stationed at Argonne is still working on improving the Atom Trap Trace Analysis detector - a device that measures potential krypton contamination. The researchers stated that they are all aiming to conduct an analysis on ice samples measuring only 20 kilograms. The ice found in the Taylor Glacier sample was discovered to be 120,000 years old; the team juxtaposed this measurement against the amount of atmospheric oxygen and methane of that period.
The ability to discover and accurately date ice is imperative for these ice samples, which have clues that will enable scientists to map out the state of the climate during that time. This data will also help them in understanding what environmental changes triggered the planet's last Ice Age.
Further details of the study were published in the April 21 issue of Proceedings of the National Academy of Sciences.
