# Geology

posted by
**Bean** on
.

Can anyone help me please? I have a sample of granite, which has been determined to have a U238-Pb date of 1120 Ma. How can I find out how this was determined? I have been trying to calculate this but my brain has frozen, so any help would be appreciated! I don't expect the answer but if I could be advised of the equation to use that would be great. Thank you!

I take it this is S103 TMA08 Q2(b) (10 marks) "The age of a granite can be determined using radiometric dating. Explain the basis for the determination of a 238U-Pb radiometric date of 1120 Ma for a granite."

The key word here is "explain". There is nothing to calculate.

The best source of information is the course books. Try Section 8.5 B10.