The 366 daily episodes in 2014 were chronological snapshots of earth history, beginning with the Precambrian in January and on to the Cenozoic in December. You can find them all in the index in the right sidebar. In 2015, the daily episodes for each month were assembled into monthly packages, and a few new episodes were posted. Now, the blog/podcast is on an occasional schedule with diverse topics, and the Facebook Page showcases photos on Mineral Monday and Fossil Friday. Thanks for your interest!

Thursday, January 30, 2014

January 30. Snowball Earth? 650-775 million years ago

By Richard I. Gibson

Here’s the podcast:



Snowball earth is the controversial idea that the Earth was entirely, or almost entirely, covered with ice and snow during three or four periods during the late Proterozoic, from about 650 to 775 million years ago. While there is abundant evidence that can be interpreted to suggest the existence of a snowball earth, much of that evidence can be interpreted in other ways as well.

The podcast outlines some of those lines of evidence. Below are some links for further reading.

http://www.snowballearth.org
http://en.wikipedia.org/wiki/Snowball_Earth
http://www.amazon.com/Snowball-Earth-Maverick-Scientist-Catastrophe/dp/1400051258
http://www.sciencedaily.com/releases/2011/10/111012083450.htm

Modern glacier photo by Dirk Beyer, under GNU free documentation license

2 comments:

  1. at minute 6 you mention Ca eroding into the ocean and "that could make less CO2" - how does that work?

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    1. Calcium in the oceans would (potentially) react with carbon in the water (or atmosphere) to make calcium carbonate (limestone) that would have precipitated and thereby sequestered the carbon. I misspoke when I said "less calcium to make CO2" - should have said "less carbon to make CO2" - because it had combined with calcium in the ocean to take it (the carbon) out of the atmosphere, therefore less CO2.

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