The Pacific Windless, formed about 10 million years ago, is significantly enriched by Beryllium-10 in comparison with older and younger layers. Scientists believe that this is the traces of an important ancient event, but before SI pores do not understand which one - three possible versions are considered, writes iflscience.
Geologists who have discovered this peak believe that this may be the result of a shift in the ocean currents, which changed the climate of the Earth for a certain period. On the other hand, scientists believe that their find may indicate a nearby supernova, which was not previously known.
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Beryllium is a relatively rare element. However, Berylli-10 helping geologists to date the deposits, too ancient to be measured by the traditional radiocarbon method. This is due to the fact that Berylli-9 is stable, while the Beryllium-10 has a half-life of 1.4 million years.
Simple words, the older the sample of sedimentary breeds, the lower the ratio of Beryli-9 and Beryli-10, or at least, would be so if the amount of berylia-10, initially postponed, was constant.
Atoms of Beryli-10 are formed in the upper layers of the atmosphere, when cosmic rays collide with oxygen molecules, and fall to Earth for a year or two. Consequently, a surge in cosmic radiation can lead to an increase in the content of beryllia-10 in the sky, and shortly after that on land or in the depths of the ocean.
According to Dr. Dominic Collmus from Helmholtz-Zentrum Dresden-Rossendorf, who found with colleagues a bursting of Beryli-10 in the samples of iron-margansky crusts, postponed about 10.1 million years ago in the central and northern part of the Pacific.
Such sampling should take into account the speed of decay of beryllium-10: less than 1% of this element, delayed at that time, will still be present. However, according to Collm, about 10 million years after this large-scale event, he and his colleagues discovered twice as much Beryli-10 than expected.
First of all, scientists checked and eliminated the possibility of the presence of pollution from later sources, where less than the beryllium-10 broke up. Thus, they were convinced of the reality of the surge and began to search for explanations.
The splash of space rays from supernova about 70 light years from us, such as causing later bursts of iron-60, is the most obvious and dramatic. However, scientists admit that other explanations are possible.
Heliosphere protects the Earth from most cosmic rays that astronauts may experience while traveling to distant space. However, the temporary weakening of the heliosphere, for example, due to passing through the interstellar cloud, is quite capable of causing a surge of Beryli-10, similar to the one that the team recorded.
On the other hand, the explanation of the surge may turn out to be oceanic, not astrophysical. It is known that the Antarctic circumpolar course sharply increased 12-10 million years ago. It is assumed that such an event could lead to an uneven distribution of Beryli-10 on the planet for a certain period of time. Note that this theory is quite easy to check:
if the samples around the world show the same growth, it will be refuted; If in other oceanic pools the levels of Beryli-10 fell at that time, so the global average indicator was quite constant, then the currents were almost certain.
Scientists also recognize that other options are possible. For example, the release of beryllia during a large event melting ice or changes in the magnetic field of the earth. However, they were subsequently rejected as too weak.
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