Proterozoic glaciation - glaciation that occurred on the border of the Proterozoic and Vendian was one of the strongest glaciations in the history of the Earth [1] .
Paleomagnetic data indicate that at that time most of the continental blocks of the earth's crust were located in equatorial latitudes and traces of glaciation were found on almost all of them (this is the basis of the global glaciation hypothesis known as Snowball Earth ). In the Proterozoic ice age there were several glaciations, and all of them were accompanied by significant changes in the carbon isotopic composition of sedimentary rocks . With the onset of glaciation, carbon deposits become sharply lightened, it is believed that the reason for this change is the mass extinction of marine organisms that selectively absorb a light carbon isotope. In the interglacial periods , the isotopic composition reversed, due to the rapid development of life, which accumulated a significant part of the light carbon isotope and increased the 13 C / 12 C ratio in sea water.
In the case of the Proterozoic glaciation, it is assumed that the cause of the retreat of the glaciers (generally speaking, glaciation is stable, and can exist indefinitely without additional factors) could be volcanic emissions of greenhouse gases into the atmosphere.
Notes
- ↑ Smith, AG Neoproterozoic timescales and stratigraphy (neopr.) // Geological Society, London, Special Publications. - Geological Society, London, Special Publications, 2009 .-- T. 326 . - S. 27-54 . - DOI : 10.1144 / SP326.2 . - .