zircons dating site
Assuming that the changes Δ C and Δ µ' both occur within roughly the same small distance δ x , the width of the interface, the helium flux J in equation (A2) becomes:
Because of their uranium and thorium content, some zircons undergo metamictization . Connected to internal radiation damage, these processes partially disrupt the crystal structure and partly explain the highly variable properties of zircon. As zircon becomes more and more modified by internal radiation damage, the density decreases, the crystal structure is compromised, and the color changes.
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Sandstones frequently contain detrital zircon grains and if these grains are undisturbed and concordant, their ages provide some clue as to their provenance. Generally at least fifty grains from each sandstone sample need to be analysed in order to obtain reliable data.