image: A piece of the EC 002 meteorite. The main mass of the meteorite resides at the Maine Mineral & Gem Museum. view more
Credit: Image credit: Maine Mineral and Gem Museum/Darryl Pitt.
Researchers report the petrological characteristics of a meteorite from an early protoplanetary asteroid. The nature of the crusts of primordial, differentiated protoplanets, which are generated through partial melting in the depths of bodies that formed in the early Solar System, is largely unknown, mostly because of a scarcity of sample material. Jean-Alix Barrat and colleagues report that EC 002, meteoritic lava found in the Sahara in 2020, exhibits a crystallization age of 4.565 billion years ago, earlier than other known samples. The authors determined the age through analysis of aluminum and magnesium isotopes and report that the crustal sample likely crystallized from a partial melt of a noncarbonaceous material formed around 4.566 billion years ago. The silica-rich chemical composition classifies the rock as andesite, which differs from the known crusts of other asteroids that are basaltic. However, the composition of the parent body of EC 002 was probably not atypical, suggesting that andesite crusts may have been common in protoplanets forming in the early Solar System. According to the authors, no known asteroid shares the chemical composition of EC 002, suggesting that early protoplanets with andesitic crusts may have either incorporated into planetary bodies or been destroyed.
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Article #20-26129: “A 4565 Myr old andesite from an extinct chondritic protoplanet,” by Jean-Alix Barrat et al.
MEDIA CONTACTS: Jean-Alix Barrat, University of Western Brittany, Plouzané, FRANCE; email: barrat@univ-brest.fr; Akira Yamaguchi, National Institute of Polar Research, Tokyo, JAPAN; email: yamaguch@nipr.ac.jp
Journal
Proceedings of the National Academy of Sciences