Possible 3.5 billion year old bacterial traces found in Pilbara

[gary]

Devin Powell in the Washington Post today is reporting on a claim by Nora Noffke,
a biochemist at Old Dominion University in Norfolk, VA, on the discovery of bacterial
traces in the Pilbara which "are the oldest fossils ever described".

Noffke was part of a group who presented the finding to the Geological Society of
America last month, so the evidence will now undergo further peer scrutiny.

Article here -
Page 1 - http://www.washingtonpost.com/nation...278_story.html
Page 2 - http://www.washingtonpost.com/nation...8_story_1.html

[astroron (Ron)]

Interesting article Gary, I hope the discovery passes peer review.
Cheers

[AstralTraveller (David)]

I just had morning tea and our geologist who specialises in old rocks and early life was in the tea room (having a break from hand-picking zircons for dating). He hadn't heard this specific claim but found it very believable. He says that the 3.4-3.5Ga (billion years ago) date has been about for decades. Generally in the Pilbra the dating is very good and the debate revolves around interpretation of the structure. In that context the carbon-isotope data is very important (but of course isotope data is always important ).

BTW in the display cases just down the corridor is a stromatolite dated to 3.45Ga and a banded iron formation (BIF) dated to 3.7Ga. The BIF contains iron oxide and that oxygen was formed by photosynthesis. Hence: life at 3.7Ga.

[alocky (Andrew lockwood)]

And let's not forget the poor old stromatoporoids! Whatever became of them?
It certainly seems ( and my former colleagues at the Geological Survey of WA often commented) that pretty much as soon as the great bombardment was done, and it was safe to stick your head up - life did. Seems like it's not such an improbable thing.
Cheers,
Andrew.

[AstralTraveller (David)]

Originally Posted by alocky

It certainly seems ( and my former colleagues at the Geological Survey of WA often commented) that pretty much as soon as the great bombardment was done, and it was safe to stick your head up - life did.

That's a geologist's 'as soon as' - about 100 million years.

[alocky (Andrew lockwood)]

Originally Posted by AstralTraveller

That's a geologist's 'as soon as' - about 100 million years.

Blink of an eye, really! Nearly long enough for light to cover some real distance.

[AstralTraveller (David)]

Well the ABC has picked up a story that reports the 3.49Ga date as 3.9Ga. So a slip of the keyboard has added >400,000,000 years to the age! You have to be so careful when reading reports about science in the general media. The oldest rocks in the Pilbra are about 3.5Ga, so the 3.9Ga just isn't possible.