This appears to be how they computed the date: https://en.wikipedia.org/wiki/K%E2%80%93Ar_dating https://en.wikipedia.org/wiki/K%E2%80%93Ar_dating With just 1

This appears to be how they computed the date: https://en.wikipedia.org/wiki/K%E2%80%93Ar_dating https://en.wikipedia.org/wiki/K%E2%80%93Ar_dating With just 1 sample they can't conclude much, but if they find a bunch of others, they'll have an interesting set of datapoints from the composition of the tiny air pockets in the ice.