Can you imagine the white bears who walk on ice floes halfway between the Earth's poles?
No, this is not a new attraction for curious travelers with deeper pockets who want to afford another unusual tour. Geologists have recently found evidence that our planet, which in our times more sweat in the recent past reminded the nearly endless icy wilderness. When this happened last time?
716.5 million years ago, when no reasonable our bipedal ancestors did not exist, even for the sake of mammals that are mentioned at the beginning of imagery. Recently, researchers found that the University Harvard (U.S.). The latest discovery is based, you will not believe, on the study of ancient rocks that are tropical - thanks to the moving surface - due in the northwestern parts of present-day Canada.
Another confirmation of the scientific assumptions, called "snow snowball Earth", at which the "third rock from the Sun" once upon a time was bound in eternal ice to the equator. The findings are, exactly, made famous in the journal Science.
Earth as a lump of snow
The first time was supported by the aforementioned cruel icing occurred near zero parallel, indicating a rare event known as "Snowball Earth", highlights the geologist Francis Macdonald. And that lasted for at least five million years!
With even one such, which later happened, was divided uu two major ice ages on our planet. It is obvious that the frozen cover in both cases cover the entire area, turning it almost into "ice land".
Survival of eukaryotes (unicellular and multicultural forms of life, other than microorganisms such as bacteria) suggests that the sun came up in certain regions, leaving not frozen water. Almost at the same time there have been the earliest animals.
Despite the omnipresent freeze, reminiscent of Francis Macdonald, the temperature was not uniform (appeared as a small deviation), and are icebergs sailed back and forth providing a sort of refuge for wildlife. Antediluvian remains (fossils) show that there were all the major groups of eukaryotes, except for animals, before the Earth was the first freeze.
If it did, then how organisms survive? Is that prompted the change (evolution) and the subsequent emergence of animals?
On the evolutionary point of view, life on Earth is always bad when confronted with an ice age that represents a serious burden.
On rocks from the Yukon (Canadian area) there are clear signs of ice accumulation and other signs of icing, such as particles or granules of departed rocks, distortions in soft sediments and applied shear remains scraped ice.
Rocks from tropical regions
On the basis of magnetism and structure, scientists are able to determine that these Canadian rocks in the ancient past, before the 716.5 million years ago, located at the level of the sea in the tropics. Ten degrees north or south of the equator.
Climate imitation (modeling) have long forecast that the entire ocean froze if extended to 30 degrees north and south latitude. It was not immediately clear what caused it and why the overall freeze over, but it coincides with the age of rocks formed from cooled magma found in the outermost Corner's northwestern Canada.
One can consider that the freeze ended abruptly or is interrupted by heavy volcanic outbursts.
Millions of years of steady succession of cold and warm period seems to be impaired - suggests lengthy duration of the freezing cold. Looking to tomorrow, there is no reasonable justification why a global freezing (and freezing) does not happen again.
Chaining our planet's eternal ice suggested five years ago Russian astronomers, led by Habibulom Abdusamatov: mid-century the planet's cooling, not warming. For that, blame the reduction of the flow of radiation from our star. The country will begin to cool from 2012 to 2013. year, a freeze will be followed by a decade and a half or two after falling the most tumultuous upheavals (activities) in the Sun (2035-2045).
No comments:
Post a Comment