Breeds related to the era of “Earth-snowballs” indicated that the transition to global icing could occur incredibly quickly.
Scientists suggest that the Earth completely (or almost completely) was covered with ice several times in its geological history. This is evidenced by glacial deposits of different epochs reaching very low latitudes, and an excess of carbon-13 in the rocks of that time, which speaks of the lack of photosynthesis, and paleomagnetic data. Princeton geologists investigated such samples found in the territory of Ethiopia and formed during one of the periods of “Earth-snowball”, during the Stortiysky glaciation of the cryogenics – about 717 million years ago.
In an article published in the journal Geology, Scott MacLennan and his colleagues showed that the diamictites studied by them are fragments of powerful boulders carried by glaciers over long distances and are of glacial origin. Below they gradually pass into the older layers of carbonates: this indicates that previously such a terrain was shallow, rich in marine microflora.
Such a picture, according to scientists, indicates that in the era of the death of the supercontinent Rodinia, the region turned from a damp and blooming tropical paradise into an icy wilderness. Judging by the lack of a clear boundary between glacial and shelf sediments, the transition occurred gradually, albeit extremely quickly: McLennan and co-authors indicate a span of 1000 to 100 thousand years.
This is a surprisingly short period, which can be explained by the action of a positive feedback between icing and an increase in the albedo of the planet. The more it was covered with ice, the more solar radiation it absorbed, but reflected into the cosmos with shiny white areas of the ice surface. And the more it continued to cool, building up new glaciers until it was completely covered by them – or almost completely.