New type of meteorite linked to ancient asteroid collision

An ancient space rock discovered in a Swedish quarry is a type of meteorite never before found on Earth, scientists reported June 14 in the journal Nature Communications.
The new meteorite, called Ost 65, appears to be from the missing partner in a massive asteroid collision 470 million years ago. The collision sent debris falling to Earth over about a million years and may have influenced a great diversification of life in the Ordovician Period. One of the objects involved in this collision is well-known: It was the source of L-chondrites, still the most common type of meteorite. But the identity of the object that hit it has been a mystery.
Ost 65 was discovered in Sweden’s Thorsberg quarry, source of more than 100 fossil meteorites. Measuring just under 4 inches wide, it looks like a gray cow patty plopped into a pristine layer of fossil-rich pink limestone. The Ost 65 rock is called a fossil meteorite because the original rock is almost completely altered except for a few hardy minerals — spinels and chromite. Analyses of chromium and oxygen isotopes in the surviving minerals allowed the researchers to conclude the Ost 65 meteorite is chemically distinct from all known meteorite types.
By measuring how long Ost 65 was exposed to cosmic rays, the team established that it traveled in space for about a million years before it fell to Earth 470 million years ago.

https://www.ucdavis.edu/news/new-type-meteorite-linked-ancient-asteroid-collision

Paper: http://www.nature.com/ncomms/2016/160614/ncomms11851/full/ncomms11851.html