Posted on 01/21/2016 12:03:46 PM PST by JimSEA
Around 720-640 million years ago, much of the Earth's surface was covered in ice during a glaciation that lasted millions of years. Explosive underwater volcanoes were a major feature of this 'Snowball Earth', according to new research led by the University of Southampton.
Many aspects of this extreme glaciation remain uncertain, but it is widely thought that the breakup of the supercontinent Rodinia resulted in increased river discharge into the ocean. This changed ocean chemistry and reduced atmospheric CO2 levels, which increased global ice coverage and propelled Earth into severe icehouse conditions.
Because the land surface was then largely covered in ice, continental weathering effectively ceased. This locked the planet into a 'Snowball Earth' state until carbon dioxide released from ongoing volcanic activity warmed the atmosphere sufficiently to rapidly melt the ice cover.
(Excerpt) Read more at sciencedaily.com ...
During the breakup of Rodinia, tens of thousands of kilometres of mid-ocean ridge were formed over tens of millions of years. The lava erupted explosively in shallow waters producing large volumes of a glassy pyroclastic rock called hyaloclastite. As these deposits piled up on the sea floor, rapid chemical changes released massive amounts of calcium, magnesium and phosphorus into the ocean.
Dr Gernon explained: "We calculated that, over the course of a Snowball glaciation, this chemical build-up is sufficient to explain the thick cap carbonates formed at the end of the Snowball event.
I need an eye exam. I thought the headline was saying “Explosive Underwear”. I thought ‘really? is it on YouTube yet? What is the catalyst for explosions? 36 x 24 x 36?”
You forget about the underwear bomber who tried to blow up a plane load of people by setting off the explosives hidden in his underwear.
That presumes Algore has actually evolved...
But of course he isn’t explaining his theory on why Rodina broke up in the first place ...
It was evil SUV's, silly...
Oh fiddlesticks I thought it was a Giant Gore stamping his huge big feet ... just silly.
Freshwater runoff from land changed ocean chemistry. Idiots. Where did the freshwater come from ? More than likely increased volcanic activity in shallow waters spewed immense amount of particulates into the atmosphere. Blocking sunlight. Course they have no way of proving that so they ignore it
It’s called snowball earth because it was covered in ice, nice fresh water ice. The melt was from the ice and picked up minerals as it ran into to ocean, changing the chemistry of the ocean.
The CO2 came largely from the volcanos.
All that ice was created by water evaporating from the Oceans. It did not just magically appear. Balance was restored when it melted.
The minerals in the ocean precipitated as they became more concentrated during the formation of the iceball. The carbonates referenced in the article are a part of this. During the snowball period, volcanos at the edges of the plate breakup introduced more minerals which mixed with those picked up in the erosion by the fresh water. There were a lot of things happening at the over the warming. Today, you can find the minerals precipitated due to the initial freezing in some lateritic ores.
That’s interesting, thanks. The immediate questions I’d have would concern the geologic evidence of something of that magnitude since we have pretty old rocks in the cratons, particularly in South Africa and Australia. Also, what effect would it have on the earth moon relationship and, if the plates were in fact forming as seems likely, what would it do to that.
What precipitates eventually redissolves. Otherwise there would be no saltwater.
Not all by any means. Look at the salt mines and other precipitate mineral deposits. New minerals from igneous rock are coming up from deep in the crust or mantle all the time.
I won’t believe any of the above hypothesis, until there is a Rodinian to give us a first-hand account of what really happened back then.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.