A lone meteorite that landed in the Sahara desert in 2020 is older than Earth. The primeval spaces are about 4.6 billion years old and are the oldest known example of magma from space.
The age and mineral content indicate that the rock was in our early origins solar system according to a new study, from the crust of a protoplanet – a large, rocky body that is evolving into a planet.
The meteorite, called Erg Chech 002 (EC 002), is probably a rare piece that survived a lost baby planet that was destroyed or absorbed by larger rocky planets during the formation of our solar system.
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Pieces of EC 002 were found in May 2020 in Adrar, Algeria, and the fragments were ‘relatively coarse grains, brown and beige’, sporadically strewn with crystals that were ‘larger green, yellow-green and less commonly yellow-brown’. according to a description by the Lunar and Planetary Institute (LPI).
EC 002 is an achondrite, a type of meteorite that comes from a parent body with a clear crust and core, and according to the Center for Meteorite Studies at Arizona State University.
About 3,100 known meteorites originate in rocky crust and mantle layers asteroids, but it reveals little about the diversity of protoplanets when our solar system was young. About 95% come from just two parent bodies, and about 75% from those come from one source – possibly the asteroid 4 Vesta, one of the largest objects in the asteroid belt, the researchers reported.
A meteoric rarity
Among the thousands of rocky meteorites, EC 002 stood out. Radioactive versions, or isotopes, of aluminum and magnesium indicate that the meteorite’s parent was an ancient body dating from 4.566 billion years ago, and the chemical composition of EC 002 revealed that it was from a partially molten magma. reservoir in the crust of the parent body. Most rocky meteorites come from basalt crust sources – rapidly cooling lava rich in iron and magnesium – but the composition of EC 002 showed that its parent’s crust was made of andesite, which is rich in silica.
“This meteorite is the oldest magmatic rock analyzed so far and sheds light on the formation of the craters that covered the oldest protoplanets,” the study’s authors reported.
Although EC 002 is highly uncommon, other studies have found that such silicons with silicon infusion were probably common during the formation of our solar system, “contrary to what the meteorite record suggests,” the researchers wrote.
“It is reasonable to assume that many similar chondritic bodies were simultaneously accreted and covered by the same type of primordial crust,” the study’s authors said. However, when scientists looked at the spectral “fingerprints” of the cosmic objects – wavelength patterns in the light they emit or reflected – and compared them to EC 002, they found no similarities. Even after comparing 10,000 objects in the Sloan Digital Sky Survey database, EC 002 was ‘clearly distinguishable from all asteroid groups’, the scientists reported. “No object with spectral properties similar to EC 002 has been identified to date.”
Where are all the protoplanets with andesite crusts today? According to the study, most of these protoplanets probably occurred in our solar system during the volatile period of planetary birth. Either they were shattered in collisions with other rocky bodies, or they were taken up by larger and more successful rocky planets, such as Earth, Mars, Venus and Mercury, which left few traces to spawn meteorites like EC 002.
“Remains of primeval enesity crust are therefore not only rare in the meteorite record, but they are also rare in the asteroid belt today,” the scientists wrote.
The findings were published online in the journal on March 8 Proceedings of the National Academy of Sciences.
Originally published on Live Science.