There is NOT one shred of evidence to date this 'find'. Reading between the lines does seem to point to the 5% of 'life' being that hidden 'origins' also described by some as a hot steaming pot of primordial soup.
I do not doubt their find but their dating is what questions their motives.
The dating of this overlaps some of the deepest layers in the Antarctic Ice Sheet overlying the Gamburtsev mountains.
The Gamburtsev's are 2.5 miles deep, are older than the Alps, yet show no signs of wear. They date back to the Carbonoferous Age ~ which is WAY back there.
So, too much CO2 led to what? Did Earth get warm and everything died? We might ask why that ice didn't melt.
The Earth itself is about 4.6 billion years old.
From Steve Jones' "Darwin's Ghost," we have on page 195 ...
"The evidence comes not from our own planet, but from its satellite. The Moon flew off its parent after a giant impact. Because it stayed small, cold and undisturbed it gives a better picture of the past than its parent. A quick trip by the Apollo XI mission was enough to date it."
The “hot steaming primordial soup” probably occurred around 3 billion years ago. This event was around 250 million years ago when there were 4 limbed land vertebrates running around. My theory is that a very large boloid may have punched into Siberia and set off the Siberian Trappes. The same thing may have also happened on the west side of India and set off the Deccan Trappes around 65 million years ago. Google Shiva Crater and Dr. Chattergee. If is apparently much larger than the Yucatan Crater that is getting most of the credit for the dinosaur extinction.