Meteorite dating question

scatterbrain8

You find a meteorite and measure a rubidium-strontium age of 4.5 billion years. However, the gas retention age of the meteorite is 1.5 billion years, and the cosmic ray exposure age of the meteorite is 10 million years. When did the meteor form? How can you reconcile the three different age measurements?



Attempt at solution: So I'm not entirely sure about this because I don't really know anything about rubidium-strontium dating, but I think that the meteor formed 4.5 billion years ago. The gas retention age would only allow us to date back to the last time the meteor had been struck hard or had been heated up enough to allow gas to escape, so this wouldn't give us an accurate measure of the age of the meteor. The cosmic ray exposure would also doesn't give us an accurate measure of the age because cosmic rays only penetrate up to about a meter. In addition, differentiation in the meteorite would probably throw this age off as the elements on the meteor that were initially exposed to the sun may have moved to somewhere else inside the meteorite by now.

Is my guess right? Or would the rubidium strontium age only tell us the age of the rock particles that formed the meteorite?

MichaelXY

http://hyperphysics.phy-astr.gsu.edu...orrbsr.html#c1

scatterbrain8

thanks, i think i've got it now.