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Paper details new groundwater dating technique

Dec. 4, 2014--Neil Sturchio, chair of the Department of Geological Sciences at University of Delaware, is co-author of a Nature Geoscience paper detailing a pioneering new technique to date groundwater.

Knowing the age of the groundwater provides important clues about the sustainability of water resources, information that is particularly important in dry or arid climates.

The technique involves measuring Krypton-81, a rare isotope produced by cosmic rays in the Earth’s atmosphere.

Sturchio explained that as rain is absorbed into the ground, a miniscule amount of the isotope comes with it. There are only about 1,000 atoms of Krypton-81 in a liter of water, but with a half-life of 229,000 years, it remains in the groundwater nearly one million years and can be tracked and quantified as it moves through the aquifer.