a) Basaltic rocks are very low in Potassium, and are thus poor candidates to get a quality radiometric date via K/Ar methods. I would have to see the original article to see why it was evern tried.
My knowledge it pretty thin on such things, but from what I know, basalts are poor rocks to date by any radiometric method. Perhaps others can chip in if and how basalts can be directly radiometricly dated.
b & c) The examples have VERY RECENTLY (earlier today!) been specificly covered at the
"Carbon-14: A Scientifically Proven Dating Method?" topic.
Moose
[This message has been edited by minnemooseus, 08-01-2003]