Sr isotope dating
They begin by cutting off the contaminated outer layers of shells found in the field. A tiny speck of dust in dirty air could alter the strontium ratio of samples and invalidate results.
The clean room is constructed virtually free of any metal fixtures, which could also contaminate samples.
The team takes the solution of pure strontium, contained in a few drops of liquid, and paints it onto a small coil of wire that they bring to an adjoining laboratory.
There, a mass spectrometer, an instrument for weighing atoms, measures the relative quantities of the two strontium isotopes.
These devices hold promise for use in spacecraft, remote weather stations, navigational buoys, etc., where a lightweight, long-lived, nuclear-electric power source is required.Seawater also contains several isotopes of strontium, two of which researchers use for dating shells: strontium-86 and strontium-87.