Snowball Earth

By: Allie Fruendt

Imagine living in Mexico, or the Bahamas, or anywhere near the equator. Then imagine that place being covered in ice, frozen. You can't survive due to the frozen Earth, only some small organisms could live in this frozen climate. That is what the Earth was like during the period called snowball Earth.

What is it?

Snowball Earth is a hypothesis that about 850-630 million years ago, the earth’s surface was completely frozen from pole to pole . There is some evidence through glacial deposits, and there is also other evidence to show this to be true. Earth's equator was covered in ice, and this is how many scientists explain how this could happen. This hypothesis is accepted by most people to show the explanations for the glacial deposits found in tropical places or places not thought to be normal. It is still not accepted by many paleontologists. Despite those, many geologists believe that snowball Earth happened, just disagree on the amount of frozen land.
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This is what the Earth is thought to have looked like when it was in the snowball Earth period. The world was frozen.

How do we know this actually happened?



There are many different pieces of evidence to show how this happened earlier in the Earth's history. One study used sedimentary rocks from Svalbard, Norway, that were part of the ice age. They found frost-shattered parts under the sediment, which is from when the Earth was very cold, when the CO2 levels were lower. The layers showed that there was ice at one point and it melted. It also showed that the earth was colder, and when it warmed, the glaciers melted which made rivers and lakes. Another study at Harvard University found volcanic rocks in Canada in between glacial deposits that were known to be left behind by melting glaciers and sediments. By using a uranium-lead mass spectroscopy, they figured out that they were deposited 716.5 million years ago, which was during the period of snowball Earth. They also figured out that that was also the time when Canada was situated near the equator, meaning that the equator was frozen. Banded Iron Formations, or BIFs, are sedimentary rocks that are made up of oxides, sulfides, or carbonates of iron. They are made when anoxic ocean becomes an oxygenated ocean. Seawater contains less than one part per billion since it is easily dissolvable. This shows that BIFs are not forming in present day. This is evidence because this means that there was most likely ice sheets over the oceans, which is how oceans can be anoxic. Since a way that an ocean can be anoxic is by little oxygen exchange with the atmosphere, the oceans could of been covered by sheets of ice. Then when snowball Earth ended, and the ice melted, the oxygenated atmosphere and the anoxic ocean could mix, which creates BIFs.
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This graph shows how the oxygen levels went up during the snowball Earth period. Ice uses more oxygen so there would be less oxygen and more glaciers, which the graph shows. This proves that this theory actually happened.

How it could affect us

Scientists know that the Earth has went back and forth from cold to warm periods. It shows that Earth is sensitive, and people can get anxious over this, which can change the world, by the people and how the earth is. Some people think that eruptions during the snowball-Earth period added sulfur particles into the atmosphere, which cools the planet and blocked more of the sunlight. One thing they could do to try to stop the Earth from warming is to do the same thing artificially.

Citations

Christine Dell'Amore, National Geographic News PUBLISHED March 5, 2010. ""Snowball Earth" Confirmed: Ice Covered Equator." National Geographic. National Geographic Society, 5 Mar. 2010. Web. 01 Apr. 2016.

Dartmouth Undergraduate Journal of Science. "Oceans of Ice: The Snowball Earth Theory of Global Glaciation." DUJS Online. N.p., 30 May 2010. Web. 01 Apr. 2016.

"Research Sheds Light on End of Snowball Earth Period." Space Daily31 Aug. 2015: n. pag. General OneFile. Web. 1 Apr. 2016.