2023-06-03 16:00:46
We know well that the climate of our planet is not immutable. Throughout the more than 4,000 million years of existence of our space rock, the climate of its atmosphere (which was born shortly after than the planet itself) has been changing on numerous occasions. But some changes have been more radical than others. The Cryogenic period is proof of this..
There was a time when the Earth was a snowball. Actually the periods were two. This geological era is called the Cryogenic period and includes a period between 720 and 635 million years ago. This geological era includes two superglaciations in which ice could cover the entire plant and an intermediate temperate period. During these ice ages the Earth became a huge “snowball” and many refer to this stage as such.
Life had already begun on Earth, indeed, even the first animals had already appeared, animals probably similar to sponges that still inhabit the seas today. It is not known exactly how he managed to endure this life. Some cyanobacteria might have survived on the ice surface, but life on our planet was already more complex than that.
The algae and the animals that feed on them they could have survived in a dark ocean, covered by a total layer of ice. That is why experts believe that there might have been a thin strip at the equator either with liquid water or with a sufficiently thin layer of ice to allow the algae to survive and with them the rest of life.
This hypothetical Earth is given the name of the “slush ball”. Some recent studies they have extended the areas in which seas could exist even to areas of intermediate latitudes.
What has happened? Experts often refer to this stage as the time when the earth thermostat broke. In the pre-Cryogenian eras, much of the Earth’s landmasses were found on the supercontinent Rodinia. The breakup of this continent may have been behind both superglacial periods: the Sturtian glaciation, the first; and the second and shorter, the Marinoana.
During continental breakup, large masses of basalt could have been exposed. Basalt has a great ability to absorb carbon dioxide from the atmosphere, which would have reduced our atmosphere’s ability to store heat.
This could have coincided with a period of low solar activity and with volcanic eruptions that would have emitted large amounts of sulfur to the atmosphere. Most likely, several of these factors would have coincided in time to have laid the foundations for one of the greatest climate changes our Earth has experienced.
Once ice spread across the planet’s surface, a new factor conditioned the situation. Since the white color of ice and snow reflects more sunlight, less radiation can be absorbed by the planetary system, which probably made the situation hold for such long periods of time (the Sturtian superglaciation lasted for more than 50 years). millions of years).
We owe the knowledge about this period to some fallen stones. Glaciers carry rocks with them that end up inside icebergs. These floating ice drag these stones and release them towards the seabed as it melts.
These rocks give rise to curious geological formations, in which a stone appears embedded between layers of sedimentary rock. The appearance of these formations in certain places and strata allowed geologists discover this planetary snow globe.
Today we can see planetary snowballs all around us. Smaller than ours, yes. These are the icy moons of Jupiter, Saturn, and Uranus. If there is life in these parts of our solar system, it will be something different from ours.
These satellites probably have oceans under their ice sheets, but no sunlight would reach them. The key could be in that case in geothermal activity, activity that, at least in some of these moons is important.
The news about changes in the Earth’s climate today usually have another face. However, these superglaciations of the past account for the important role of the composition of the atmosphere in the climate.
It is unlikely that we will experience such a glaciation in the future, although minor glaciations are to be expected at some point. Such changes might not pose a threat to all life on the planet, but they certainly would pose a great risk to human civilization as we know it.
In Xataka | 20,000 years ago Africa was the paradise of penguins: until they found a good reason to flee from there
Image | Oleg Kuznetsov, CC BY-SA 4.0
1685818088
#superglaciation #period #Earth #life #confined #narrow #band