Recent research has found the chemical signature of life in rocks
said to be 3.7 billion years, This is 200 Ma earlier than the
earliest known fossils (photosynthetic cyanobacteria). The news
report is at
http://cnn.com/TECH/science/9901/28/science.life.reut/index.html
The researchers have studied graphite in metamorphic rocks:
"The levels of carbon-12 and carbon-13 were similar to those found in
more modern deposits, which scientists know include the waste products
and remains of plankton.
They took this as good evidence that the rocks contain the chemical
traces of very ancient plankton -- which would logically have been one
of the earliest forms of life on Earth.
"These data and the mode of occurrence indicate that the reduced
carbon represents biogenic detritus, which was perhaps derived from
planktonic organisms," they wrote. "
Last year, I participated in discussions on the alleged reducing
atmosphere of the early Earth, and posted a contribution on Archaean
oil. In the latter post, I said:
"I have found this extremely interesting, as it was not that long ago
that the Archaean was portrayed as a world unsuitable for life as we
know it. Now we find evidence that the aqueous Archaean was teeming
with life - with the possibility of using biomarkers to find out more
as to what kinds of life were represented."
This latest study is a significant step in this direction.
Furthermore, since the graphites go back almost to the time of the
great bombardment, the data further constrains theories about the
"Origin of life". The resource of seemingly unlimited time is no
longer available to the advocates of abiogenesis.
Best wishes,
David J. Tyler.