Carbon dating of fossils older than 10,000 years

[heartless]

Hello,
I'm just wondering, is it fine to predict the age of fossils older than 10,000 years with Carbon Datin? After all, I think nobody knows how much carbon-14 there was back then, and whether the animals consumed less or more carbon-14 than now. How exact are such long-term predictions?

 

[Mk]

http://www.ingentaconnect.com/content/arizona/rdc/2001/00000043/00000002/art00008

ca60,000 years is pretty much the limit

See: http://en.wikipedia.org/wiki/Radiocarbon_dating#Calibration

 

[GeekyGuy]

ca60,000 years is pretty much the limit

Anything older you'll need to use potassium-40.