Submarine volcanoes and mid-ocean ridges are born in an extremely strange process - it turned out that the sea floor can literally tear itself apart, releasing lava flows to the surface, according to an article published in the journal Nature.
“Mid-ocean ridges were considered to be a kind of analogs of volcanoes on the surface of the ocean floor, which work in the same way as their land“congeners”. We found that they should be viewed as some kind of breaks in the crust through which lava seeps,”said Yen Joe Tan of Columbia University in New York (USA).
Mid-ocean ridges are gigantic mountain ranges at the bottom of the world's oceans, arising at points where tectonic plates of the earth's crust collide or diverge. Under these ridges, according to scientists today, a new crust appears and the old crust sinks into the depths of the Earth's interior. Such submarine ridges are always surrounded by volcanoes and geysers, "black smokers", whose emissions become a source of food for many underwater organisms.
Until now, according to Tan, scientists believed that such ridges and volcanoes were formed in the same way as their land counterparts - as a result of the appearance of a giant "bubble" of lava under the crust, which rises to the surface of the Earth and presses on the upper layers of rocks. Over time, this hot matter breaks out and a volcano or magma outpouring occurs.
Tan and his colleagues found that, in fact, the emergence of volcanoes and new ridges under water occurs in a completely different way, observing the birth of one of these structures in the Pacific Ocean, in fact at the equator itself, in 2005 and 2006.
To do this, scientists made a series of dives into one of the most troubled zones near the so-called East Pacific Rise, an underwater ridge 8 thousand kilometers long, and installed a set of seismometers and microphones there. After a while, a new eruption took place here, the results of which literally forced the authors of the article to completely reverse their ideas about geology.
As it turned out, a new series of volcanic eruptions in this fault did not occur gradually, as the theory predicted, but in fact simultaneously, when a giant line-crack 35 kilometers long appeared at the bottom of the Pacific Ocean, through which lava rushed to the surface. This whole process was accompanied by powerful explosions, pops and other loud sounds, which, as scientists believe, were caused by the contact of water and lava.
Using recordings of these sounds and data from seismometers, scientists discovered that their sources were regions covered with freshly hardened lava. Judging by the weak seismic shocks emanating from these points during the cataclysm, the earth's crust here literally broke into two halves literally by itself, without "help" and pressure from the lava rising from the depths.
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This is supported by the fact that magma rose to the surface of the ocean floor evenly - four eruptions occurred at the bottom of the fault along the fault line, and not one, as happens in the case of the birth of a "normal" volcano on land.
Their eruptions were very short - they lasted only two days, and during this time the bottom of the Pacific Ocean was covered with 22 million cubic meters of fresh rocks, which is approximately 5% of the volume of all people living on Earth. This is a relatively small volume for a fault of such length that scientists again associate it with the fact that it was generated not by the pressure of magma, but by the rupture of the crust.
Why does the sea crust burst on its own? Scientists don't know this yet, but they speculate that such rifts may be caused by the fact that tectonic stress in sea tectonic plates increases as they begin to sink under continental plates. The answer to this question will be found only when geologists accumulate a sufficient amount of data on such "breaks", scientists conclude.