Finding old ice samples is important because it helps scientists construct and fine-tune ancient climate models.The latest krypton-based dating technique shows that the ice from Taylor Glacier in Antarctica is around 120,000 years old.Just so that we are clear, researchers here are using krypton- the noble gas and not , which is a fictional material that weakens the otherwise invulnerable hero, Superman.
"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," said Christo Buizert, a postdoctoral researcher at Oregon State University and lead author of the study.
"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." What is Krypton dating?
Krypton is a noble gas that doesn't interact with chemicals. The gas is produced by cosmic radiation hitting Earth and is trapped in air bubbles in the Antarctic ice.
The technique of krypton dating is much like the popular carbon-14 dating method that measures the radioactive decay of a known isotope and compares it with a stable isotope. The versions arise due to difference in the number of neutrons in the atoms.
Krypton isotope called krypton-81 decays slowly while krypton 83 doesn't decay.
The proportion of both isotopes gives researchers an estimation of the age of the ice.
Krypton-81 exists in small quantities, which is why it was never really used in scientific studies in the past.
However, a breakthrough in detector technology in 2011 enabled scientists to count the number of Krypton-81 atoms with greater accuracy, paving way for its use in age-estimation studies.
The new atom counter called Atom Trap Trace Analysis, or ATTA was developed by Zheng-Tian Lu at Argonne National Laboratory near Chicago.