|2011-12-13 00:25:51||Cryogenian blog post?|
As some of you may have guessed I have a certain fascination with the climate changes of the past, their causes and effects. Guess it's my geology background!
A few weeks ago I became annoyed with a sweeping generalisation made by Monckton on WUWT: "In the Neoproterozoic, 750 Ma BP, CO2 concentration (today <0.04%) was ~30%: otherwise the ocean’s magnesium ions could not have united with the abundance of calcium ions and with CO2 itself to precipitate the dolomitic rocks laid down in that era. Yet mile-high glaciers came and went twice at sea level at the equator."
In a very rare post on that site, I called him out on it but he wouldn't bite, except to tell another poster that he got the info from Plimer, but the encounter prompted me to obtain the latest in the literature on the Cryogenian. Monckton has mentioned this ancient glaciation many times and it is time that the reality was set out. Over the coming months I'll put a blog-post together on this subject if you like. It's a fascinating subject, especially because we are dealing with a very different Earth, where the rise of photosynthetic life, a massive atmospheric oxygenation event, the cessation of banded iron-formation deposition, glaciation, CO2 and carbonate deposition as caps on glacial sequences all form parts of the puzzle (may need to be a two-parter!)...
Cheers - John