Geologists found traces of the primary rocks of the Earth in Hawaii

Geologists found traces of the primary rocks of the Earth in Hawaii

MOSCOW, 7 APR — RIA Novosti. Scientists have found in emissions of volcanoes in the Hawaiian Islands traces of the rocks, which were formed only 50 million years after the birth of the Earth and cooling its primary matter, according to a paper published in the journal Science.

“We found in these rocks geochemical markers, formed nearly 4.5 billion years ago. We were particularly pleased to find such ancient traces in the rocks formed very recently. We don’t know how they managed to “survive” for so long a time, but we have some ideas on this,” said Andrea Mundl (Andrea Mundl) from the University of Maryland, College Park (USA).

Today geologists are actively debating about when in the bowels of the Earth tectonic processes start, when did it first continents, and when our planet got its magnetic shield, which protects life from cosmic rays and solar wind.

On this account there is no consensus. In recent years, theorists and geologists practicing found a lot of evidence that the movement of tectonic plates could be launched almost immediately after the birth of the Earth, and through almost a billion years after its birth. Recently, geologists have found tentative traces of the primary crust of the Earth in the North-East of Canada pointed out that tectonics has started not at once.

Mandl, and her colleagues found an example of a more deep-seated rocks of time “the creation of the Earth”, studying the emissions of volcanoes in the Hawaiian Islands. Analyzing the proportion of isotopes in the rocks that were thrown on the surface of the Earth in 1959, during the eruption of Kilauea volcano, scientists noticed something unusual — the proportion of the isotopes of helium and tungsten were not similar to anything on Earth.

In them, as says Mundl, contained an unusually high number of helium-3 and a few tungsten-182. This combination suggested to the researchers that they are dealing with the most ancient rocks on Earth.

The fact that the tungsten-182 there is only one way — through the collapse of a highly unstable hafnium-182, whose half-life is only 9 million years. This ensures that the entire hafnium-182 was supposed to disappear from the rocks of the Earth 50 million years after the birth of the Solar system.

This allows the use of tungsten-182 as an indicator of the age of the rocks, as his share will be higher due to the tendency of the tungsten to migrate to the core of the planet, in more ancient rocks, and lower in younger rocks, experiencing fully melted. Similarly, the rocks that rose to the surface from the core, will have an unusually low concentrations of tungsten-182, as it just did not have time to stoop to such depths.

Another indicator of the age of rocks is the concentration of helium-3 — the more, the ancient breed, as his “big brother” helium-4 occurs in the decay of uranium, thorium and other radioactive elements and mixed with “primary” helium-3 in the smelting process.

Accordingly, the combination of a high proportion of helium-3 and a low percentage of tungsten-182, as explained, Mundl, says that the Kilauea volcano has thrown away the oldest rocks of the planet, which was formed in the first 50 million years of life in the Solar system. The study of these primary rocks, as scientists hope, will help us understand what was the Ground in the first moments of his life and how features of its structure that might affect its further evolution.