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Geological processes for zircon + sandstone?

Zircon crystals formed when a granite magma crystallised. Since then, geological processes have caused some of these crystals to end up with grains in a sandstone. What sequence of events would account for this?

and what implications would this make for the age of the sandstone assuming that the 206Pb/238U ratio is 0.90 with the radiometric decay worked out as:

t = 1/k x ln (1+ D/P)
t = the age of the sample
D = number of atoms of the daughter isotope in the sample
P = number of atoms of the parent isotope in the sample
k = decay constant of the parent isotope
ln = natural logarithm

The half-life of 238U is given to us as 4.47 billion years, which equals 0.693/k. So our formula becomes:
t = 4.47 x10^9 /.693 x ln (1+ .9)
t = 6.45 x10^9 x 0.642 =4.14 x10^9 years

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Zircon crystals possess high stability and durability and thus are likely to remain intact as they are incorporated into sedimentary rocks. In this case, the granite ...

Solution Summary

The expert examines geological processes for zircon and sandstones. The implications are analyzed.