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Lone meteorite that landed in the Sahara Desert in 2020 is older than Earth. The primitive space rock is around 4.6 billion years old and is the oldest known example of space magma.
Its age and mineral content suggest that the rock originated from our solar system crust of a protoplanet – a large rocky body developing into a planet, according to a new study.
The meteorite, called Erg Chech 002 (EC 002), is probably a rare surviving piece of a lost baby planet that was destroyed or absorbed by larger rocky planets during the formation of our solar system.
Related: Space-y Tales: The 5 Weirdest Meteorites
Fragments of EC 002 were found in Adrar, Algeria, in May 2020, and the fragments were “relatively coarse-grained, light brown and beige”, sporadically interspersed with crystals that were “larger green, yellow-green and less often yellow-brown “. according to a description of Lunar and Planetary Institute (LPI).
EC 002 is an achondritis, a type of meteorite that originates from a parent body with a distinct crust and core, and lacks round mineral grains called chondrules, according to the Meteorite Studies Center at Arizona State University.
About 3,100 known meteorites originate from the crust and mantle of rock layers asteroids, but they reveal little about the diversity of protoplanets when our solar system was young. About 95% are from just two parent bodies, and about 75% of these are from a single source – possibly asteroid 4 Vesta, one of the largest objects in the asteroid belt, reported Researchers.
A meteorite rarity
Among the thousands of rocky meteorites, EC 002 stands out. Radioactive versions, or isotopes, of aluminum and magnesium indicated that the meteorite’s parent was an ancient body dating to 4.566 billion years ago, and the chemical composition of EC 002 revealed that ‘it emerged from a reservoir of partially melted magma in the crust of the parent’s body. Most rocky meteorites originate from sources with basaltic crusts – rapidly cooled lava that is rich in the iron and magnesium – but the composition of EC 002 showed that its mother’s crust was made of andesite, rich in silica.
“This meteorite is the oldest igneous rock analyzed to date and highlights the formation of the primordial crusts that covered the oldest protoplanets,” the study authors reported.
Although EC 002 is very unusual, other studies have shown that such silica-infused andesite crusts are likely to be common during the protoplanet-forming phase of our solar system, “contrary to what the archives of meteorite, ”the researchers wrote.
“It is reasonable to assume that many similar chondritic bodies accreted at the same time and were capped by the same type of primordial crust,” said the study’s authors. Yet when scientists examined the spectral “fingerprints” of distant cosmic objects – the wavelength patterns in the light they emit or reflect – and compared them to EC 002, they found no match. . Even when compared with 10,000 objects in the Sloan Digital Sky Survey database, EC 002 was “clearly distinguishable from all groups of asteroids,” the scientists reported. “No object with spectral characteristics similar to EC 002 has been identified to date.”
Where are all the andesite-crusted protoplanets today? During the volatile period of planetary birth of our solar system, most of these protoplanets probably did not go beyond childhood, according to the study. Either they were shattered into pieces in collisions with other rocky bodies, or they were absorbed by larger and more successful rocky planets, such as Earth, Mars, Venus and Mercury, leaving little trace to spawn meteorites such as EC 002.
“The remains of the primordial andesitic crust are therefore not only rare in the meteorite archive, but they are also rare today in the asteroid belt,” the scientists wrote.
The results were published online on March 8 in the journal Proceedings of the National Academy of Sciences.
Originally posted on Live Science.
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