By: Allie Fruendt
What is it?
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.
How it could affect us
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.