What dating method do they use to determine the age of really old fossils?

southeastside: What dating method do they use to determine the age of really old fossils?
Yesterday there was news of a 3.3 million year old Australopithecus afarensis fossil from Ethiopia. I’m just curious as to how they ascertain the age. I know it’s not carbon-14 dating, that’s 2 orders of magnitude beyond its range. It’s been a while since I learned about this stuff, so thanks for refreshing my memory.

Answers and Views:

Answer by Steve
The site I use is match.com The old fossils don’t have a picture there.

Answer by yscrk
Sending the Old fossil on a date with a Blonde, Brunette and a red head – he may react to one of them

Answer by tbom_01
Looks like there’s aluminum, chlorine, calcium & iodine dating…
https://en.wikipedia.org/wiki/Cosmogenic_isotope#Applications_in_geology_listed_by_isotope

Answer by Corey M
radioactive dating, using certian elements such as carbon-14, scientists are able to figure out how old a fossil was

Answer by Roy
They measure the decay of other radioactive elements, not carbon. The half life of carbon 14 is only 15,000 years or so. For anything older than that they measure for example, how uranium decays into lead. The article below may help.

Answer by bootleg
check it out on hhp://www.wikipwdia.org