The mysterious outbreak of volcanism, which occurred in the south of Europe about 5-6 million years ago, was associated with the fact that the Mediterranean at that time almost completely dried up and its waters ceased to “press” on the earth’s crust, according to an article published in the journal Nature Geoscience.
“Approximately 5.9-5.3 million years ago, the frequency of volcanic eruptions in the Mediterranean was twice as high as the norm.” Logically, only the drying out of the entire sea could have strongly influenced the depths of the Earth and made them more active in producing magma of the entire region, “said Pietro Sternai of the University of Geneva in Switzerland.
Sterne and his colleagues studied the roots of one of the most mysterious events in the history of the relatively recent geological past of the Earth – the so-called Messinsky salinity peak, a fantastic crisis of its magnitude, which occurred about 5-6 million years ago.
At this time, as scientists say, the Mediterranean Sea experienced some of the fastest and most severe episodes of shallowing and even drying, during which it almost completely dried up or turned into a set of unrelated salt lakes, and then re-filled with water.
Traces of this cataclysm are the multi-kilometer salt deposits on the southern coast of Europe. All this happened in a flash of an eye by geological measures – the waters of the sea evaporated into the air for about a thousand years, and they returned even faster – in just a few months.
In those days, when the bottom of the former Mediterranean Sea was dry, there was really hellish conditions – the air temperature often exceeded 80 degrees Celsius, and the pressure was 1.5 times higher than at sea level today. Why this happened, the scientists do not know yet – some believe that the tectonic plates, whose movement blocked the Strait of Gibraltar, and others – the formation of Antarctic ice that lowered the level of the ocean, were “to blame” in this event.
Similar events, as Sternay tells, never pass without a trace for the bowels of the Earth. For example, the completion of the glacial period and the retreat of the polar ice of the Earth to the north led to the fact that some regions of America today literally fall under water at a very high rate because of the disappearance of the mass, which supported them to “weight.”
Such considerations forced scientists to verify what had changed in the lithosphere of Europe after the disappearance of almost 4.4 quadrillion tons of water from the former Mediterranean Sea. As these calculations showed, the sea level drop of two kilometers and its breakdown into several large “lakes” should lead to the fact that the pressure of water on the crust of the Earth in the vicinity of Italy, Morocco and Sicily was to fall sharply.
This, according to the researchers, led to a sharp increase in volcanism, as magma flows could now move unchecked to the surface of the Earth, without overcoming the pressure of the giant “water column” of the Mediterranean Sea, which pushed south of Europe and north Africa.
Traces of this process, according to Sternay, can be seen in the sediments of volcanic rocks in those regions of the Mediterranean, where water losses were the highest. For example, over a million years of the Messinian crisis, in Italy and other hot spots, there were 10-13 major volcanic eruptions, and not 4-5 events of this kind, like today or before the drainage of the sea.
In addition, the discovery of this unusual relationship between volcanoes and sea level, according to Sterne, is another argument in favor of a “fast” theory of the development of the Messinian crisis. According to him, a similar outbreak of volcanism could occur only if the water evaporated very quickly, and this indicates the complete blockade of Gibraltar at the time of the onset of this disaster. Similar consequences can be expected by the Earth in the future, if the sea level changes dramatically, scientists conclude.