Provocative new research published this month in the journal Geology suggests that oceanic plate subduction was operating from the earliest times in Earth’s history, meaning conditions for the formation of life may have existed up to a billion years earlier than generally thought.
Not entirely sure what to make of this announcement. As I understand it, we have uncontroversial fossil evidence going back 3 billion years. However, those fossilized singled celled organisms are considered too advanced to be the earliest life, and there are possible fossils going back 3.5 billion years. (‘Possible’ because they could be non-biological formations).
If this announcement is referring to the 3.5 billion number, that would put life starting in the Hadean, the period where Earth was basically just an ocean of magma, which seems unlikely. Which means the announcement must be referring to the period around 4 billion years ago.
If so, this puts life happening as soon as the surface cooled enough to be solid, and before the late heavy bombardment, perhaps even before the planetary collision that formed the Moon.
Interesting, but it’s still just the conditions for life. No evidence for life itself that early. At least not yet.
- Earth’s crust tells a different story (sciencealert.com.au)
- Third Time’s a Charm (geopolicraticus.wordpress.com)
- Origin of water on Earth (en.wikipedia.org)
- What Is a Subduction Zone? (livescience.com)
- ODU professor, team uncover oldest fossils yet (hamptonroads.com)