Sea-level rise following a Snowball Earth

I’ve long wondered if the high Ca ions in the post-glacial seas facilitated the formation of hard parts/exoskeletons in animals

The Cryogenian Period (850 to 635 Ma) of the Neoproterozoic is named for the intense glacial episodes recorded in strata of that age. There were two that palaeomagnetism  in glaciogenic sedimentary rocks indicates that ice covered all of the continents including those in the tropics, and a third, less extreme one. These episodes, when documented in the 1990s, became dubbed, aptly enough, as ‘Snowball Earth’ events. But evidence for frigidity does not pervade the entire Cryogenian, the glacial events being separated by long periods with no sign anywhere of tillites or glaciomarine diamictites shed by floating ice. Each Snowball Earth episode is everywhere overlain by thick carbonate deposits indicating clear, shallow seas and a massive supply of calcium and magnesium ions to seawater. The geochemical change is a clear indicator of intense chemical weathering of the exposed continents. The combination of Ca and Mg with carbonate ions likewise…

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