ALH 84001 (abbreviation of Allan Hills 84001) is a 1.93 kg meteorite found in 1984 on the Allan Hills ice field, Antarctica (Victoria Land), by US meteorite searchers. ALH 84001 has been classified as achondrite and is thought to be from Mars. It mainly consists of coarse-grained cataclastic orthpyroxene-rich material and among the SNC meteorites defines the class of SNC-orthopyroxenites. In 1996, NASA scientists announced that the meteorite might contain fossils of Martian microorganisms, a view that has been widely criticized. Radiometric dating suggests that ALH 84001 is 4.1 billion years old. The piece of rock has been ejected from Mars by an impact event 15 million years ago. Thirteen thousand years ago, the meteorite landed on Earth.