Long-lost ‘extinct’ meteorite found

Unusual space rock fragment may have come from 470-million-year-old cosmic collision


ROCKY REMAINDERS  A new meteorite (dark area, center) discovered embedded inside red limestone may have formed during the same space crash that formed L chondrites, one of the most abundant meteorite groups on Earth.

Birger Schmitz

A long-lost sibling to one of Earth’s most common kinds of meteorite has finally been found. The discovery could help scientists piece together a half-billion-year-old hit-and-run, the researchers propose online June 14 in Nature Communications.

Searching through a Swedish quarry, researchers discovered a new variety of meteorite that may have originated from the same cosmic collision that formed L chondrites, which make up around 40 percent of all meteorites. Scientists think L chondrites are the shards of a giant space rock — maybe an asteroid, maybe not — that collided with an asteroid around 470 million years ago. While L chondrites are abundant, fragments of the mysterious object have been elusive, making this explanation difficult to prove.

Geologist Birger Schmitz of Lund University in Sweden and colleagues uncovered the newly discovered meteorite, nicknamed Öst 65, alongside more than 100 L chrondrites. Dating showed that Öst 65 formed within a million years of the L chondrite‒forming collision. That timing is close enough to suggest the two meteorites could have been born from the same smashup.

Öst 65 may be the first documented example of an “extinct”meteorite, the researchers propose. L chondrites still fall to Earth, but Öst 65 doesn’t show up among new meteorites, suggesting that its parent body was completely obliterated by collisions long ago.

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