The Compleat Advocate

[sschulin]

Oldest rocks have sharply different isotope signature

In a paper published online on July 8, 2009 [L.P. Knauth and M.J. Kennedy, Nature doi:10.1038/nature08213; 2009], the authors report findings of their study of carbonate rock such as limestone. In the rocks dated as being over 850-million years old, they find starkly different isotopic signatures, compared to the younger rocks.

The evidence of widespread plant life doesn't appear in the fossil record until about 400-million years ago (using the same kind of dating assumptions that have long been in vogue amongst the scientific community). In a news feature published in the print edition of the journal [Nature 460:161, July 9, 2009], paleobiologist Nick Butterfield is cited as noting the discrepancy between when evidence of plant life appears in the record and when Knauth and Kennedy hypothesize that enough plant life was present to account for the isotopic signature of the rocks:

... to have the effect on the carbonate record that they see, the ancient photosynthetic life would have needed to be operating on the scale that it is today — a worldwide carpeting of green. And that should have left something for posterity, says Nick Butterfield, a palaeobiologist at the University of Cambridge, UK. "In order to have a significant impact it has to be everywhere, all over the place," he says. "And it can't be, unless it has seeds and cuticles and adaptations for covering vast amounts of the terrestrial surfaces. If you've got those adaptations you can't avoid turning up in the fossil record."

See the news article at
http://www.nature.com/news/2009/090708/full/460161a.html