Chemical etching of polished internal surfaces of these minerals reveals spontaneous fission tracks, and the track density can be determined.
Because etched tracks are relatively large (in the range 1 to 15 micrometres), counting can be done by optical microscopy, although other imaging techniques are used.
And then, it also wasn’t cool at the time to date a top guy.
So I had to struggle with you know, the heat of being with Mark and, that’s the only reason I was on TV and blah blah blah.
400 km to the south but the syenites of Kangerdlugssuaq cluster around 50 m.y.