4 ms·

I thought early Earth had no free oxygen with which to oxidize metal until life started producing it as a waste product? Isn't that why the banded iron formatio

• meindnoch 2y ago
  Banded iron formations are iron oxide, not elemental iron. Vast amounts of iron were dissolved in Earths oceans, until oxygen produced by photosynthesis oxidized it, to form iron oxide, which precipitated and sank to the bottom. This process went on for 2.5 billion years until all the dissolved iron was consumed.
• gus_massa 2y ago
  > I thought early Earth had no free oxygen [XXX] until life started producing it as a waste product? It's correct, but metal did get oxidized abyway before that. Don't expect to time travel and see bunchs of metalic Sodium. I'm only 99% sure thre was neither metalic Iron. Anyway, I googled https://en.wikipedia.org/wiki/Banded_iron_formation https://en.wikipedia.org/wiki/Banded_iron_formation The idea is that the water alewady had oxidized iron(2+) and some bacterias oxidized it to iron(3+) that is no so soluble and then you got deposits of mixed iron(3+), iron(2+) and oxygen (2-).