The same effect was also used in understanding brain development by looking at Carbon isotopes in brains of people born before WW2 to determine which cells were formed when.
That's fascinating to me, I didn't realize anthropogenic radiation levels were significant enough to offer a control for molecular examination of human brains in the general population.
It’s not “radiation levels” per se. Nuclear bomb testing in the mid 20th century dramatically increased the amount of carbon-14 in the atmosphere, which has subsequently been gradually declining. https://en.wikipedia.org/wiki/Carbon-14#Origin
The same effect was also used in understanding brain development by looking at Carbon isotopes in brains of people born before WW2 to determine which cells were formed when.