Early Earth Atmosphere More Oxidized Than Previously Thought

[Azathoth]

Plate tectonics also says nothing about the oxidation state of the atmosphere

I can quote wikipedia too

The Great Oxygenation Event (GOE), also called the Oxygen Catastrophe or Oxygen Crisis or Great Oxidation, was the biologically induced appearance of free oxygen (O2) in Earth's atmosphere. This major environmental change happened around 2.4 billion years ago.
Photosynthesis was producing oxygen both before and after the GOE. The difference was that before the GOE, organic matter and dissolved iron chemically captured any free oxygen. The GOE was the point when these minerals became saturated and could not capture any more oxygen. The excess free oxygen started to accumulate in the atmosphere.
The rising oxygen levels may have wiped out a huge portion of the Earth's anaerobic inhabitants at the time. Cyanobacteria, by producing oxygen, were essentially responsible for what was likely the largest extinction event in Earth's history.[citation needed] Additionally the free oxygen combined with atmospheric methane, triggering the Huronian glaciation, possibly the longest snowball Earth episode ever.

http://en.wikipedia.org/wiki/Great_Oxygenation_Event

[Schneibster]

Plate tectonics also says nothing about the oxidation state of the atmosphere

But if plate tectonics had already begun, much of the carbon dioxide would be trapped in carbonate rocks and then pushed into Earth’s interior. In 2001, a climate model by Dr. Sleep and Kevin Zahnle of the NASA Ames Research Center found that the late Hadean Earth then would have been somewhat chilly.

http://www.nytimes.com/2008/12/02/scien ... ted=2&8dpc

I can quote wikipedia too

The Great Oxygenation Event (GOE), also called the Oxygen Catastrophe or Oxygen Crisis or Great Oxidation, was the biologically induced appearance of free oxygen (O2) in Earth's atmosphere. This major environmental change happened around 2.4 billion years ago.
Photosynthesis was producing oxygen both before and after the GOE. The difference was that before the GOE, organic matter and dissolved iron chemically captured any free oxygen. The GOE was the point when these minerals became saturated and could not capture any more oxygen. The excess free oxygen started to accumulate in the atmosphere.
The rising oxygen levels may have wiped out a huge portion of the Earth's anaerobic inhabitants at the time. Cyanobacteria, by producing oxygen, were essentially responsible for what was likely the largest extinction event in Earth's history.[citation needed] Additionally the free oxygen combined with atmospheric methane, triggering the Huronian glaciation, possibly the longest snowball Earth episode ever.

http://en.wikipedia.org/wiki/Great_Oxygenation_Event

How about Nature?

[Schneibster]

Again, over here I got not just one, but two completely separate groups of scientists, both finding the same thing. Over there, some random dude on the Internets.

Good luck with that. Find another buck and a quarter and you can get a cup of coffee.

[Azathoth]

You actually have two groups of scientists finding different things. One study is concerned with temperature and the other is concerned with oxygen. As to the ad homs how many scientists and studies do you think it took to arrive at the evidence supported status quo? Why do you think your two studies are superior? The first is nonsense from an exobiogenesis crank and goes into realms only previously travelled by creationists. The second has a wikipedia stub to attest to it's widespread acceptance in the scientific community

[Azathoth]

How about Nature?

My resorting to wikipedia was in response to yours. Have a page of results for a quick search on nature for great oxygenation event

http://www.nature.com/search/executeSea ... &submit=go

That it happened is not disputed except by the occasional nutter. The nature papers tend to be a bit more involved as to specific aspects of it

[Schneibster]

http://www.geology.wisc.edu/zircon/cool ... _home.html
http://earthobservatory.nasa.gov/Features/Zircon/
http://adsabs.harvard.edu/abs/2001AGUSM...V51A01V
http://www.scientificamerican.com/artic ... arly-earth

[Azathoth]

I'm more willing to give credence to the second. Earlier emergence of plate tectonics still doesn't point in any way to an oxidising environment before the great oxidation event though.

[Schneibster]

I think the Great Oxygenation Event is a red herring. It happened 2 and a half billion years ago, considerably after the times that we're talking about here over a billion years earlier.

[Schneibster]

I am by no means done. Do you need ten more references? Or have I made that point sufficiently that you're going to stop with the appeal to authority horseshit?

It's a common fallacy to denigrate any appeal to authority, when the only one that's wrong is to an authority that is invalid.

When I see a press release from a large university, and some random dude on the Internets denies it and calls the professors and researchers working at the large public university "cranks," I get real suspicious real fast.

[Azathoth]

I would love to see ten more references advocating an oxidising Hadean. So far only the OP has sunk to those depths

[Schneibster]

From the article linked in the OP:

The New York Center for Astrobiology

Based within the School of Science at Rensselaer Polytechnic Institute in Troy, N.Y., the New York Center for Astrobiology is devoted to investigating the origins of life on Earth and the conditions that lead to formation of habitable planets in our own and other solar systems. Supported by NASA, the $7 million center is a member of NASA's Astrobiology Institute (NAI), and is a partnership between Rensselaer and the University at Albany, Syracuse University, the University of Arizona, and the University of North Dakota. Researchers and students within the center seek to understand the chemical, physical, and geological conditions of early Earth that set the stage for life on our planet. They also look beyond our home planet to investigate whether the processes that prepared the Earth for life could be replicated elsewhere — on Mars and other bodies in our solar system, for example, and on planets orbiting other stars.

So a NASA-supported US$7 million center partnering with Albany, Syracuse, the University of Arizona, and the University of North Dakota are all "exobiology cranks."

OK.

[Azathoth]

I'm sure they do some decent research too. I don't hold out much hope for their next funding review if they regularly make logical jumps like they did here in their conclusions.

[Schneibster]

Here's an article from the Geology Department at the University of Wisconsin-Madison, on zircons and oxygen isotope analysis. And that's from 2002, nine years ago.

Of course no one's done any new research since then. /sarcasm

[Schneibster]

I'm sure they do some decent research too. I don't hold out much hope for their next funding review if they regularly make logical jumps like they did here in their conclusions.

The results quantify the nature of gas molecules containing carbon, hydrogen, and sulfur in the earliest atmosphere, but they shed no light on the much later rise of free oxygen in the air.

I'm sure they'll be fine.

[Azathoth]

Missed that. OK I was wrong. They are advocating higher concentrations of oxidised compounds in the atmosphere rather than an oxidising atmosphere. I can get on board with that