[Nebullis]

The controversy over the early fossils continues.

When Schopf published a paper in Nature, last December, claiming new lines of evidence for the fossils, an article by Brasier, in the same issue, claiming the fossils are artifacts. Schopf has been fairly silent but for a partial retraction, i.e., the fossils are not cyanobacteria, but he insist they are biogenic. The age of the fossils is not in question. Three months later, Pasteris and Wopenka published a paper in Nature claiming that the the laser-Raman spectroscopy that Schopf used as evidence in the December paper does not indicate biogenic origin. Schopf counters that such wasn't the only line of evidence, that cellular morphology and carbonaceous molecular-structural make-up supports the biogenic origin of the Raman signature.

I'm sure we haven't heard the end of it.

[Alamo-Girl]

Thank you both so very much for the background information on the dispute and the positions taken! I look forward to the results of the November meeting. Hopefully all the parties will put their cards "on the table" so we can have a better understanding.

Schopf has been fairly silent but for a partial retraction, i.e., the fossils are not cyanobacteria, but he insist they are biogenic

The above article includes this statement from Schopf which didn't sound like a retraction to me:

Schopf is having none of this. For starters, he calls the argument over cyanobacteria a "red herring. I have referred to these specimens as 'cyanobacterium-like,' 'possible cyanobacteria,' and even 'probable cyanobacteria,' but I have never, ever claimed that they were cyanobacteria per se. Nobody goes to look at the literature. I defined these taxa as being of uncertain systematic position. I said they were prokaryotes [microorganisms without cell nuclei], and still think they are, but I didn't know for sure then, and I don't know now, precisely what kinds of bacteria they are."

As for Brasier’s contention that fossils could not be found in a hydrothermal or volcanic structure, Schopf says that, while the conditions of deposition remain contentious, "It’s perfectly fine for there to be organisms in hot springs. Hot springs today are teeming with life; think of Yellowstone. If there was life around [3.5 billion years ago], it would be astounding that it was not present in such a hot-spring environment."