The rising temperatures, and increased oceanic surface area - due to reduced ice cover and rising sea levels - at the end of a glaciation increase the rate of precipitation.
High concentrations of greenhouse gases such as carbon dioxide (CO2) must build up in the atmosphere to overcome the effect of the high reflectivity (albedo) of ice and allow temperatures to rise sufficiently to begin melting.
This would weather exposed silicate and carbonate rock, including readily-attacked glacial debris, which would release large amounts of calcium. When washed into the ocean, these precipitate to form distinctively textured layers of carbonate sedimentary rock.
A heavily debated cap carbonate appears at the top of the Gaskiers Glaciation, believed by many to be global in extent.
- What are Cap Carbonates? at www.snowballearth.org
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