This is an interesting not fully resolved debate in geology/paleontology. This is a great article that discusses some of the need for the debate, and the comments on the article in later issues name some of the other major players. I think anyone interested in the question of life in the universe outside of our own little biosphere might enjoy reading this as an intro to the debate:
The timeline in the article shows the Late Heavy Bombardment dropping lots of asteroids on the Earth until about 3.8B years ago. The alleged stromatolites are from ~3.7Bya. 200My at that point isa but of a big deal.
Not in terms of life origin (we exist regardless of the answer) but it seems that having life that early pushes back the boundary of a hellish earth versus a blue marble earth, which may have implications on other hypotheses and assumptions about the evolution of the Solar system.
Admittedly, this is far, far from my field. Just trying to think through potential implications.
The folks who argue for a "blue marble" Earth early on, even in the Hadean (>4 billion years ago) are fond of pointing out that while the name was chosen to evoke a hellscape, Hades in Greek mythology ruled over an underworld that was not particularly hot or hellish
Excuse me sir, this was a hilarious quip and not a shallow dismissal. Probably my comment is still against site rules in this case, but it was lighthearted and delightful, not dismissive.
Ok, point taken about it not being dismissive. It's hard to tell sometimes!
Jokes aren't against the rules but they have to be pretty good not to count as unsubstantive comments. Most people overrate how funny their jokes are. See https://news.ycombinator.com/item?id=7609289.
Toward the end of the article they go on to explain that these rocks that aren't fossils fail to exhibit a number of traits that they expect from rocks that are fossils.
I still remember the moment when I read that fossils weren't bones. Actually, I had read that several times before, but this time the text told me HOW they weren't bones.
I had the same confusion as a child. I read all about dinosaurs, but couldn't really grasp that the bones were truly long gone. I still remember being upset that many museums had casts of the original fossils on display. I wanted to see the original bones! I didn't really understand until later that at least visually there wasn't much meaningful difference.
https://www.sciencedirect.com/science/article/pii/S1342937X1...
It's available on Research Gate, too.