re:age of Earth

[@lepomis.psych.upenn.edu, @uga.cc.uga.edu:Schwimm@USCN.BITNET (Paleontology Columbus College, Georgia)]

Scott Horton posts:
"age of the earth is 4550 years old..."

Gee, that's precise.  I wonder how the extra 50 is determined since the
oldests rx are ca. 3951 +/- about 100my (Isua Greenland) and we have some
allochems in Australian rx perhaps 4.1 ga, moon rx dated ca. 4.5 ga +/-
at least 100 my and some meteoric stuff with the same error factor.

  I teach students in my historical geology class that Earth is minimally
4.5 ga but may be as old as 5.0 or more in a poorly consolidated  form: I
believe noone has more precise data.  I'd be curious if Scott knows of
sources I don't.

cheers,
david schwimmer
schwimm@uscn.cc.uga.edu