A fragile, charcoal-like meteorite that plummeted on to a frozen Canadian lake last January may represent the most primitive solar system material yet studied, according to new research reported in the 13 October issue of the international journal Science. The Tagish Lake meteorite is a carbonaceous chondrite, a rare class of ancient meteorite that includes water-altered minerals and organic compounds.
Carbonaceous chondrites make up only two percent of all meteorite finds.
Analysis of the meteorite's mineral composition and oxygen and carbon isotopes reported by Peter G. Brown at The University of Western Ontario, Canada and colleagues suggests that Tagish Lake may represent a new class of carbonaceous chondrites, more primitive than any yet found. Using numerous eyewitness accounts, photographs, videos, and satellite data of the meteorite's fiery and dramatic entrance into Earth's atmosphere, the researchers also calculated Tagish Lake's origin, its path through space, and its average velocity. Brown and colleagues suggest that the meteorite came from the middle of the asteroid belt with an orbit intersecting the Earth's orbit. The asteroid belt is located between Mars and Jupiter. Fragments of the Tagish Lake meteorite should aid scientists in their reconstruction of the early solar system environment, particularly the types and amounts of elements present in the original solar nebula.