The biosphere … beginnings

At www.sciencedaily.com/releases/2011/05/110518121227.htm 'Young Graphite in Old Rocks challenges the Earliest signs of Life' … (the same story can be found at www.geology.com May 24th) and it seems that carbon found within ancient rocks has played a leading role in the development of a time-line for the emergence of biological life on earth. The rocks have been dated millions and even billions of years in the past – but now it has been found graphite (a carbon) dates somewhat younger, even very much younger, in what are some of the oldest rocks on earth in NE Canada. The research has been published in Nature Geoscience 2011, DOI:10.1038/ngeo1155 and it suggests carbon in other rocks may also be much younger than assumed. This implies the biosphere of the earth may have evolved millions of years later than currently thought, or the general consensus time-line allows. Basically, it was found the rock itself had been subject to metamorphosis yet the graphite present was not.