[edit] Hadean/Archean 4030

The latest (2008) opinion from International Commission on Stratigraphy is that Hadean preceeds Eoarchean at 4030 Ga, where Eoarchean is defined by earliest known rocks, see stratigraphy.org, select "On the Geologic Time Scale 2008", go to page 11 in the PDF. I don't propose immediate action on this, since "earliest known rocks" is a moving target and so not very well chosen. But if to preserve the pretty early on defined Eoarchean, the beginning of Late Heavy Bombardment would be a better starting point, because it is most probably a real event, that most probably can be dated, and that most probably has a sharp initial peak. ... said: Rursus (bork²) 10:07, 21 January 2009 (UTC)