Talk:Earth's early atmosphere had abundant oxygen

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I removed this response which overlaps with the others:

1. This claim attempts to argue against abiogenesis on the grounds that oxygen, a highly reactive element, would necessarily have "poisoned" any possible abiogenesis event. This claim is false, strictly speaking; oxygen atoms which are safely locked up in comparatively inert molecules, such as CO₂, would have little or no effect on any abiogenesis event. Thus, it is not enough merely to establish that the Earth's early atmosphere contained oxygen. If you want this oxygen to be a problem for abiogenesis, you also have to establish that the oxygen in Earth's early atmosphere was free oxygen, that is, raw molecules of O₂. This latter proposition is likely to be exceedingly difficult to establish, because of so-called "banded iron", a geological phenomenon which does not form in the presence of a significant level of free oxygen. The youngest deposits of banded iron have been dated to approximately 1.7 billion years ago, and the oldest deposits have been dated to approximately 3.8 billion years ago -- and the oldest evidence of terrestrial life dates back to roughly 3.5-3.8 billion years ago.

But there are different time scales for the banded iron in the this response and the others. Are those just different estimates or is one of them older and less exact? --tk 20:19, 30 Nov 2004 (UTC)

[1]

Link [1] doesn't work. Johan Karlsson 12:42, 13 October 2007 (BST)

Oops! My mistake. I just needed to refresh my browser. Sorry. Johan Karlsson 12:43, 13 October 2007 (BST)

source

This claim is very specific in associating early life and oxygen-rich atmosphere. I could not find the claim in Life--. A source needs to be located or the claim and responses changed.