Geoff

1950 was the agreed upon definition for 'present' for radiocarbon labs during
the 1960s, 1970s, 1980s, and even 1990s.

However, there was a strong push at the last radiocarbon congress to
change "B.P." to be defined as 2000 instead of 1950.  I don't know the outcome
for sure, but I was under the impression that the definition may have
officially changed; certainly some labs are now using 2000 instead of 1950.

(Maybe someone who gets Radiocarbon will have the definitive word)

dave browman