Arizona Meteorite Points to Source of LL Chondrites

Dust cloud of the Dishchii'bikoh meteorite fall
Dust cloud of the Dishchii'bikoh meteorite fall photographed from Phoenix, Arizona. Photo: Mike Lerch, Phoenix. Photo courtesy SETI Institute.

The 2016 Dishchii’bikoh meteorite fall in the White Mountain Apache reservation in central Arizona has given scientists a big clue to finding out where so-called LL chondrites call home. 

LL chondrites originate from somewhere in the asteroid belt between Mars and Jupiter, where a parent body broke up and created a family of asteroids long ago. Occasional collisions with those family members eject rocks into orbit around the sun. When these small asteroids collide with Earth’s atmosphere, they cause a bright meteor from which pieces survive sometimes and fall on the ground as meteorites.

New data helps show that LL chondrite meteorites like Dishchii’bikoh came from the edge of the asteroid belt closest to Earth, from a region in the belt near the plane of the planets. The results were published April 14, 2020, in the journal Meteoritics and Planetary Science.

“We want to know where they originated because the damaging Chelyabinsk airburst of February 15, 2013, in Russia was caused by a particularly large 20-meter sized LL chondrite,” said Peter Jenniskens, lead study author and meteor astronomer with the SETI Institute and NASA Ames Research Center.

Researchers at UC Davis investigated whether Dishchii’bikoh could have formed on the same parent body as Chelyabinsk. “Oxygen and chromium isotopes confirm a similarity in material type,” said study co-author Matthew Sanborn, a project scientist in the Department of Earth and Planetary Sciences in the UC Davis College of Letters and Science.

Read the full story from the SETI Institute.