Hi,
The quote function isn't working for me at the moment, but Dean said ....
"[1] Carbon dating is only good for stuff up to 50,000 years old - other
isotopic dating techniques are used for things older than this."
It's true that radiometric dating is the most accurate and robust available provided you have suitable material and you generally (always??) need a closed system. For the age range we are discussing U-Th is the most suitable but I believe suitable material is fairly rare in archaeological sites.
In the Australian context at least probably the best dating method is optically stimulated luminescence dating (OSL). It is used to date the last exposure of a sediment to light, thus giving its burial age. So one doesn't date the bone or artifact directly but dates the burial of the material around it. The age range is from as recent as a few hundred years out to possibly a million. OSL dates of 55ka on mud nests overlying rock art are the oldest reliable dates for Aboriginal occupation of Australia.
http://crustal.usgs.gov/laboratories...hat_is_tl.html
http://cas.uow.edu.au/laboratories/index.html