A meteorite discovered in Algeria's Sahara Desert predates Earth by millions of years. Its extraordinary age and mineral makeup reveal origins in the crust of a long-lost protoplanet.
The unique meteorite EC 002 was found in May 2020 amid the Erg Chech sand sea. Unlike typical chondrites—aggregates of dust and rock—it displayed an igneous texture laced with pyroxene crystals.
Classified as an achondrite, it derives from volcanic material of a differentiated parent body boasting crust and core. Of roughly 3,100 known achondrites, most trace to rocky asteroids; 95% from just two parent bodies, including the massive asteroid Vesta. EC 002 defies these norms.
Aluminum and magnesium isotope analysis dates its parent body to 4.566 billion years ago.
Its composition indicates formation in a partially molten crustal magma reservoir. While basaltic crusts—iron- and magnesium-rich cooled lava—dominate most achondrites, EC 002's silica-rich andesite sets it apart.
Andesitic crusts like this were likely widespread on protoplanets during early Solar System formation.
Spectral comparisons with known asteroid groups yielded no matches.
Researchers thus propose EC 002 as a fragment from a protoplanet destroyed or accreted into larger rocky worlds amid the chaotic birth of our Solar System, where few planetary embryos survived.
Details appear in Proceedings of the National Academy of Sciences.
