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Posted on 06/16/2009 4:15:19 PM PDT by SunkenCiv
BIFs, as they're known to geologists, are enigmatic. All seem to have started out as sediments on ancient seafloors, and by some estimates the oxide mineral accumulated in all known BIFs contains about 20 times as much oxygen as today's atmosphere does. Yet some of these deposits accumulated long before Earth's atmosphere became thoroughly oxygenated, so the source of the oxygen stored in these BIFs is baffling.
Then there's the mysterious banding, in which thin layers of iron-rich minerals such as hematite (Fe2O3) and magnetite (Fe3O4) alternate with silica-rich, iron-poor bands, usually of jasper and chert.
Finally, some of the BIFs are puzzling simply because they're so big: They stretch for hundreds of kilometers, a distance over which the banding apparently remains intact. So whatever processes created these formations must have acted over broad areas.
Countless details regarding these formations' origins are hidden because many older BIFs are metamorphic rocks -- they've been physically warped and chemically cooked deep within the planet, sometimes for millions of years...
New research is shedding some light on when, and how, some of Earth's most voluminous banded iron formations developed. Most of the largest formations date from the late Archean eon, which ended around 2.5 billion years ago, and the early part of the eon following it, the Proterozoic. This transition between eons is thought to mark huge environmental changes, specifically the switch from a mostly methane or carbon dioxide atmosphere to an oxygen-rich one friendly to complex life. The actual timing and suddenness of the change -- an occasion so momentous that scientists have dubbed it the Great Oxidation Event -- generate debate.
(Excerpt) Read more at sciencenews.org ...
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Somewhere around the time of Noah there was a sure enough climate change and all the Algores suffered a close encounter with the Almighty kind.
The man behind the Great Oxidation Event.
Wouldn’t the rust age naturally follow the iron age?
Andy Warhol Oxidation 1978
Or Sunspots
:’) Is that a pole-ish joke?
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