Posted on 05/10/2009 6:46:26 PM PDT by neverdem
A 250-million-year shutdown of volcanic activity which is thought to have occurred early in Earth's history may be what turned the planet into a glacier-covered snowball. It could also have helped give rise to our oxygen-rich atmosphere.
Previous studies have noted that very little volcanic material has been dated to between 2.45 and 2.2 billion years ago, but it was widely assumed the gap would vanish as more samples were dated. Now an analysis of thousands of zircon minerals collected from all seven continents indicates that the gap may be real after all. Zircons provide a record of past volcanic activity, as the date they were formed can be calculated from the radioactive isotopes they contain.
The failure of so many samples from all over the world to fill the gap suggests there was a major slowdown in the planet's volcanic activity during this period, says Kent Condie of New Mexico Tech in Socorro, who led the study (Earth and Planetary Science Letters, DOI: 10.1016/j.epsl.2009.03.033). "Volcanism didn't shut off, but it became much, much less widespread during this time."
The lull could be tied to a pause in the motion of tectonic plates, which drives much of Earth's volcanic activity, Condie says. Computer simulations suggest this motion, which now takes place continuously, would have been intermittent early in Earth's history, when the planet's interior was hotter and less viscous, so less able to drag the plates.
The lull may in turn be a major factor behind a suspected "snowball Earth" event between 2.4 and 2.3 billion years ago, when much of the planet is thought to have been covered with ice (New Scientist, 2 December 2006, p 14). With no new carbon dioxide being spewed from volcanoes, its...
(Excerpt) Read more at newscientist.com ...
Snowball Earth ping!
We’re all gonna die!!!!!!!!!!!!!! LOL
So... A single big volcano can cause a year without summer.
A Pinatubo sized volcano can lower global temperatures for years.
But an absence of volcanos freezes the planet?
And man has ruined it all in just a hundred years or so.
Not only has man ruined it here, but also have caused the polar caps on Mars to start melting, and probably is the reason there have been no sunspots for such a long period...
The Chicken Little Global Weather Disaster Thing again? Man has been bitching about the weather since the Garden of Eden expulsion. Get over it!! Adam screwed us.
Anything to tie CO2 to warming.
There are several different snowball Earth scenarios proposed for different periods of time.
We are currently in the grip of a world-wide ice age that's been underway for over 2 million years. However, the ice doesn't form all the way to the equator except in the mountains.
Algore has an army of acolytes who argue that water ice cannot normally exist on Earth.
It's a regular ol' disaster magnet.
Just about now some of the "residual" volcanism located along various "failed rifts" in the middle of the continent ought to be perking up in response to the loss of the mile deep ice cap that used to be there.
Check out "chestnut ridge" in South Eastern Indiana. There's an ancient pluton underneath that's still quite hot. The area just to the East is made up of feldspar ~ spewed up as the pluton spread lava in a crack in the continent overhead.
The ice has been coming and going, and moving that rock up and down 20 times in 2 million years. Who knows what might happen next. There's a similar formation at the bottom of Lake Superior.
At least we have something to look forward to...
These GOV paid “studies” always seem to come up with stuff that no one can prove or dis-prove. They are quite successful at keeping the GOV grants rolling in, by helping algore and his buddies sell all those fake carbon credits.
I like the way the titles always have words like “largest”, “oldest”, “fastest”, etc.
Then you read the fine print and see all kinds of “May be’s” and “could have’s” and “might’s”.
Not even science anymore. It’s rumor mongering.
Makes exciting Discovery Channel shows, if you like 40 ways to doom and gloom.
Hate Crime Legislation - Back Door to Censorship
George Will: Upside-Down Economy Great quote in comment# 17!
Fred Barnes: Be the Party of No ( "It's the route to Republican landslides." )
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Thanks for the ping!
>> So... A single big volcano can cause a year without summer.
A Pinatubo sized volcano can lower global temperatures for years.
But an absence of volcanoes freezes the planet? <<
We need volcanoes to occasionally spew CO2 into the atmosphere otherwise we start running out of CO2 and without any CO2 plants will die and the earth will reflect more sunlight back into space due to less albedo effect from veggy-tation, So warm up your SUV and give some help to the plants and the carbon cycle!
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