A meteorite that formed before the earth was discovered in the Sahara. Scientists believe that it was formed as part of an ancient planet that existed at the dawn of the birth of the solar system.
The meteorite that fell in the Sahara Desert turned out to be older than the Earth itself – this is the conclusion made by French scientists who studied the composition of the unusual stone. As the study showed, it was formed in the bowels of an ancient protoplanet, on which volcanic processes took place.
Several pieces of a meteorite with a total mass of 32 kilograms were discovered in May 2020 in the Erg Chech region, a sandy desert in western Sahara, in the southwestern part of Algeria. The debris immediately attracted attention, as it was clear to experts that the samples did not belong to chondrites – the most common of the meteorites found on Earth.
Chondrites contain chondrules, spherical formations less than a millimeter in diameter, predominantly of silicate composition.
In contrast to them, in the composition of the Erg Chech 002 meteorite, inclusions of pyroxene crystals were found, on the basis of which the meteorite was assigned to the class of achondrites.
Achondrites do not contain chondrules and are igneous (igneous) rocks or breccias, detrital rocks formed during impact processes. It is believed that such meteorites were formed as part of large bodies or ancient planets that once underwent internal separation into a core and crust.
According to statistics, out of several tens of thousands of registered meteorites, only about 3 thousand are achondrites. Most of these meteorites are of lunar or Martian origin and basalt in their composition. On the contrary, Erg Chech 002 contains no basalt, but andesite igneous volcanic rock.
This circumstance makes Erg Chech 002 extremely rare, especially considering its age. Having studied the radioactive isotopes of aluminum and magnesium, scientists have found that these elements crystallized 4.565 billion years ago as part of the parent body, which itself formed 4.566 billion years ago (according to modern concepts, the age of the Earth is 4.54 billion years).
Unlike basalt, which is formed by the rapid cooling of lava rich in magnesium and iron, andesite is created mainly from sodium-rich silicates. On Earth, it forms in the so-called subduction zones at the boundary of lithospheric plates, along which some blocks of the earth’s crust sink under others.
To find asteroids similar in composition to EC 002, scientists compared the spectra of all known groups with the spectrum of this meteorite. “EC 002 is clearly different from all groups of asteroids, and so far not a single object with similar spectral characteristics has been found,” experts say.
Despite the fact that the andesite-containing meteorite Erg Chech 002 is truly unique, a similar composition for it was common for ancient planets of the early solar system, the researchers say.
Where did the protoplanets go, the andesite of which was found in the meteorite? The authors of the work suggest that during the turbulent period of the early solar system, the protoplanets either smashed against each other or were swallowed up by larger planets such as Earth, Venus, Mars, and Mercury.
Meanwhile, British scientists reported the discovery of an extremely rare meteorite, fragments of which were found after observing a bright fireball in the area of the highway in Gloucestershire in February this year. According to experts, this is the first meteorite collected in the UK in the last three decades, its fragments were transported for study to the Natural History Museum in London.
The meteorite was classified as a carbonaceous chondrite; it may contain amino acids, ingredients necessary for life. According to scientists, about 50 similar meteorites have been found in the world.
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• Barrat, J., Chaussidon, M., Yamaguchi, A., Beck, P., Villeneuve, J., Byrne, D., . . . Marty, B. (2021, March 16). A 4,565-my-old andesite from an extinct chondritic protoplanet.
• Christian, J. (2021, March 09). Scientists believe they found a chunk of an ancient planet in Africa.
• Starr, M. (n.d.). This is a piece of a lost protoplanet, and it’s officially older than earth.
• Weisberger, M. (2021, March 08). 4.6-Billion-Year-Old meteorite belongs to Earth’s Long-lost baby cousin.