what the fuck, that's wild. also first time I've seen an article include one of these ( how plain the Language is is up for debate)
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Plain Language Summary
Plate tectonics provides a basic framework for understanding geological processes on Earth. Although the subduction of cold and heavy oceanic lithosphere can maintain the operation of plate tectonics, its initiation mechanism remains unclear. To reveal the origin mystery of plate tectonics, it is necessary to clarify how and when the first subduction on Earth began. In this study, we propose a hypothetical model that links Earth's biological processes with the origin of plate tectonics. In the photic zone of the Neoarchean continental margins, the anaerobic metabolism of photoferrotrophic bacteria greatly promoted the massive deposition of magnetite-rich banded iron formations (BIFs). Our mechanical calculations show that within an acceptable sedimentary thickness, these heavy BIF deposits can provide enough downward force to rupture the Neoarchean continental margins and initiate the earliest subduction. The peak deposition of BIFs in 2.75–2.4 Ga further implies the onset time of global plate tectonics.
Yeah, definitely needed a real TLDR, thanks. This is one where I'd love like a quanta article to get perspective from folks in the field about how controversial this proposal actually is.
Just hit me that (it true) this would have preceded the first of life's known major change to the environment, the Great Oxidation Event. So not only once but twice in an early era life totally disrupted the "normal" surroundings and caused utter chaos for existing life, which had to adapt to a new world. Next question, would these bacteria have been the same culprits?
anaerobic metabolism of photoferrotrophic bacteria
Suggests no? Because the great oxidation was caused by the development of photosynthesis as used in chlorophil. Staring at this page on iron-oxidizing bacteria, none of the key reactions have elemental oxygen as a by-product. Definitely not an expert, could be reading this wrong.
Researchers suggest that about 2 1/2 billion years ago, bacteria caused iron to precipitate out of the oceans, depositing 1 km of heavy rock layers every million years. It eventually punched through Earth's crust and initiated the plate tectonic cycle. Since then, plate tectonics has helped to stabilize Earth's climate.
Interesting idea. I never thought that the thin crust needed some push to start cycling, I figured the circulation underneath was enough since it has been going for billions of years. But let's not forget the real MVP, because without Theria slamming into the early Earth and forming the Moon from some of the lithosphere, the crust would have been too thick for any movement regardless.