What really happened prior to 'Snowball Earth'?

Jan 27, 2012
In a study published in the January 2012 issue of Geology, Swart suggests that the large changes in the carbon isotopic composition of carbonates which occurred prior to the major climatic event more than 500 million years ago, known as "Snowball Earth," are unrelated to worldwide glacial events. Credit: UM/RSMAS

In a study published in the journal Geology, scientists at the University of Miami (UM) Rosenstiel School of Marine and Atmospheric Science suggest that the large changes in the carbon isotopic composition of carbonates which occurred prior to the major climatic event more than 500 million years ago, known as 'Snowball Earth,' are unrelated to worldwide glacial events.

"Our study suggests that the geochemical record documented in rocks prior to the Marinoan or 'Snowball Earth' are unrelated to the glaciation itself," said UM Rosenstiel professor Peter Swart, a co-author of the study. "Instead the changes in the carbon isotopic ratio are related to alteration by freshwater as sea level fell."

In order to better understand the prior to 'Snowball Earth', the research team analyzed geochemical signatures preserved in carbonate rock cores from similar climactic events that happened more recently — two million years ago — during the Pliocene-Pleistocene period.

The team analyzed the ratio of the rare isotope of carbon (13C) to the more abundant carbon isotope (12C) from cores drilled in the Bahamas and the Enewetak Atoll in the Pacific Ocean. The geochemical patterns that were observed in these cores were nearly identical to the pattern seen prior to the Marinoan glaciation, which suggests that the alteration of rocks by water, a process known as diagenesis, is the source of the changes seen during that time period.

Prior to this study, scientists theorized that large changes in the cycling of carbon between the organic and inorganic reservoirs occurred in the atmosphere and oceans, setting the stage for the global glacial event known as 'Snowball Earth'.

"It is widely accepted that changes in the carbon during the Pliocene-Pleistocene time are the result of alteration of rocks by freshwater," said Swart. "We believe this is also what occurred during the Neoproterozoic. Instead of being related to massive and complicated changes in the carbon cycle, the variations seen in the Neoproterozoic can be explained by simple process which we understand very well."

Scientists acknowledge that multiple sea level fluctuations occurred during the Pliocene-Pleistocene glaciations resulting from water being locked up in glaciers. Similar changes during the Neoproterozoic caused the variations in the global carbon isotopic signal preserved in the older rocks, not a change in the distribution of carbon as had been widely postulated.

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More information: The study, titled "Does the global stratigraphic reproducibility of 13C in Neoproterozoic carbonates require a marine origin? A Pliocene-Pleistocene comparison" was published in the January issue of the journal Geology.

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User comments : 18

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GSwift7
3 / 5 (6) Jan 27, 2012
So the cause of the snowball earth event remains a mystery if this guy is correct. I never really believed the carbon cycle explaination anyway, due to the relative timing of events.
rawa1
1.1 / 5 (12) Jan 27, 2012
So far I assumed, the Snowball Earth period had been caused with impact of many tiny comets.
Parsec
5 / 5 (16) Jan 27, 2012
So far I assumed, the Snowball Earth period had been caused with impact of many tiny comets.

I find that entirely consistent with your avocation of every crack-pot idea on the planet. This however is a new one, so I'll bite.

1) What would cause a whole lot tiny comets to impact the earth like that?

2) Unless you think its was something that only happened to the earth, and not say... to the moon, where is the evidence something like that even occurred in the first place? I assure you that the evidence would be quite obvious if it existed.

3) what is the putative mechanism between lots of tiny comets and almost the entire planet being covered with ice?

4) Why do you nearly always automatically assume that you know better than people who have been studying this stuff for years? Scientists can be wrong for sure. And conventional wisdom has often been proved incorrect. But its almost always after painstaking experiment and research by scientists.
GSwift7
4.3 / 5 (11) Jan 27, 2012
I find that entirely consistent with your avocation of every crack-pot idea on the planet. This however is a new one, so I'll bite.


I nominate this for comment of the Month. I litterally laughed so hard my chair almost tipped over.

Can you post it again so that I can give it another 5/5?
GSwift7
3.7 / 5 (3) Jan 27, 2012
I think maybe he's confused between snowball earth and the possible "nuclear winter" following a catastrophic volcano or impact event. If that's the case Rawa1, you should know that the snowball earth event lasted a very long time, and the "nuclear winter" caused by an impact would be a much shorter event.
Callippo
1 / 5 (12) Jan 27, 2012
What would cause a whole lot tiny comets to impact the earth like that?
I've to admit, I don't understand such a question. Or do you really believe, such an event is really impossible? Can you explain SOHO pictures like this one?

http://sohowww.na...1024.jpg
Why do you nearly always automatically assume that you know better than people who have been studying this stuff for years?
I see, we have a tiny personal problem here....;-) Nope, I don't care what the people who are have been studying this stuff for years are thinking about. Should I do?
Callippo
1 / 5 (12) Jan 27, 2012
I litterally laughed so hard my chair almost tipped over.
It just illustrates your long-term frustration from my comments. You can recognize hidden friends and enemies easily just at the moment of public attack. Many people are losing their facade in this moment: it's gregarious instinct.
jibbles
5 / 5 (1) Jan 27, 2012
well, you see, comets are snowballs so, um, if enough of them start falling to blot out the sun then i'm sure all that ice that was turned into liquid, gas, and plasma by the impact energy will refreeze and to give you -- snowball earth! point, game, set and match rawa. thank you rawa! where would we be without you?
Crazy_council
1 / 5 (2) Jan 28, 2012
i wander if there would be anyway of mesureing the output from the sun at that time, maybee on the moon or another planet or comet, more and more studdies seem to be suggesting that the earths natural cycles could not cause this, so for me, its between biology ( microbes ) or sun output
Anda
5 / 5 (1) Jan 28, 2012
I find that entirely consistent with your avocation of every crack-pot idea on the planet. This however is a new one, so I'll bite.


I nominate this for comment of the Month. I litterally laughed so hard my chair almost tipped over.

Can you post it again so that I can give it another 5/5?


Agree... Poor Calippo/Rawa1, nobody loves you, everyone's against your stupid ideas with our gregarious instinct :)
Callippo
1 / 5 (4) Jan 28, 2012
Poor Calippo/Rawa1, nobody loves you
Jonathan Swift: When a true genius appears in this world, you may know him by this sign, that the dunces are all in confederacy against him.
deepsand
5 / 5 (7) Jan 28, 2012
What does it say when all the dunces support him?
Callippo
1 / 5 (3) Jan 29, 2012
Richard Feynman "The next great awakening of the human intellect may well produce a method of understanding the qualitative content of the equations."

Apparently, many people here don't really think like the Feynman.
roboferret
5 / 5 (6) Jan 30, 2012
But the fact that some geniuses were laughed at does not imply that all who are laughed at are geniuses. They laughed at Columbus, they laughed at Fulton, they laughed at the Wright Brothers. But they also laughed at Bozo the Clown.
- Carl Sagan
rawa1
1 / 5 (3) Jan 30, 2012
? Bozo the Clown didn't spread any theory.
roboferret
5 / 5 (4) Jan 30, 2012
Neither are you, and you're both funny :)
rawa1
1 / 5 (3) Jan 30, 2012
OK, better funny than wrong.
roboferret
5 / 5 (4) Jan 30, 2012
That's a false dichotomy.

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