The method was successfully tested in Antarctica recently

Apr 22, 2014 07:17 GMT  ·  By

A collaboration of investigators from the Oregon State University (OSU) and the US Department of Energy's (DOE) Argonne National Laboratory (ANL), near Chicago, announces the development of a new dating technique that allows for determining the age of ancient Antarctic ices with great accuracy. This method could improve our understanding of the natural cycles of ice ages on Earth. 

The new investigation was supported by grants from both the US National Science Foundation (NSF) and the US National Oceanic and Atmospheric Administration (NOAA). During the Antarctic trials, the team successfully used a novel radiometric-Krypton-dating (rKd) technique to confirm the age of an ancient ice sample known to be 120,000 years old.

What makes this new dating method so important is that it can assess the ages of much more ancient samples with greater accuracy than other approaches can. This means that glaciologists could reconstruct Earth's icy history in much greater detail and at higher resolution levels than ever before, thus revealing more data about how the ice age cycle occurs.

Understanding this complex mechanism is very important for our ability to predict how the planet will react to phenomena such as global warming and climate change. Earth went through these types of events before, but their causes were natural, not anthropogenic. Figuring out how these differences influence the natural planetary cycles is therefore essential, scientists say.

Details of the new method were published in this week's issue of the esteemed journal Proceedings of the National Academy of Sciences (PNAS). The lead author of the study was OSY postdoctoral researcher Christo Buizert. The expert and his group say that this method is now the most accurate in the world for testing the age of ice samples.

“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. 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,” Buizert explains.

In the new method, the age of ice samples is determined by studying the ratio of stable krypton-83 isotopes to radioactive krypton-81 isotopes. This element is produced on Earth when cosmic rays bombard the surface and is stored within tiny air bubbles in Antarctic ices. The isotope ratio measurement approach is also used in the much more famous carbon-14 dating techniques.

“The international scientific community is really interested in exploring for old ice […] and this new dating will really help. There are places where meteorites originating from Mars have been pushed out by glaciers and collect at the margins. Some have been on Earth for a million years or more, so the ice in these spots may be that old as well,” concludes OSU geologist and study coauthor Edward Brook.