Ageing rocks & Earth Sciences.

[IamScience]

Hello all,

Could anyone explain how to estimate the age of rocks (I have to age Granite if that helps).

 

Thanks

[fiveworlds]

http://www.geocraft.com/WVFossils/DatingMethods.html

 

The Carbon 14 test would be inappropriate for something like, say, granite because what we already know about granite is that it is too old and of the wrong composition for that test. But the granite may very well contain traces of the elements Uranium, Rubidium, or Potassium, and a test using one or more of those isotope procedures may well be appropriate and yield good results.

 

Search for radiometric dating

http://en.wikipedia.org/wiki/Radiometric_dating

Edited August 29, 2014 by fiveworlds

[Ophiolite]

Are you asking about absolute ages, or relative ages?

[fiveworlds]

Are you asking about absolute ages, or relative ages?

 

Would that not depend on the sample of granite itself? Relative ages of rocks are usually used when materials are lacking radioactive isotopes for absolute age. Though an interesting use of relative ages is when studying ice core samples

Edited August 29, 2014 by fiveworlds

[studiot]

Is this a (small) rock sample or a full outcrop?

 

If the latter, do you have stratigraphic information about the rocks the granite has intruded into?

 

It will be younger than any of these.

[pavelcherepan]

Usually you'd be using U-Pb radiometric method for older granites and granodiorites and for younger rocks U-Th method can be used. But this probably won't be possible for you. If you could answer studiot's question it will help a lot.

 

fiveworlds, using ice core samples will help us exactly how? Also, I don't think it's an ice core in the picture, looks like a normal PQ size drill core.

Edited April 22, 2015 by pavelcherepan

[Acme]

Is this a (small) rock sample or a full outcrop?

If the latter, do you have stratigraphic information about the rocks the granite has intruded into?

It will be younger than any of these.

Usually you'd be using U-Pb radiometric method for older granites and granodiorites and for younger rocks U-Th method can be used. But this probably won't be possible for you. If you could answer studiot's question it will help a lot.

Good answers.

 

fiveworlds, using ice core samples will help us exactly how? Also, I don't think it's an ice core in the picture, looks like a normal PQ size drill core.

I agree that ice cores have nothing to do with the OP, but that is a photo of an ice core from Wikipedia. The caption to it is: GISP2 ice core at 1837 meters depth with clearly visible annual layers.

Ice cores @ Wiki