The Aggie Creek Meteorite

About the size and shape of a small ham, Alaska's Aggie Creek meteorite weighs a hefty 58 pounds. Its metallic nature is obvious from the appearance of the two faces from which samples have been cut away, otherwise it looks like a rusty orange rock.

The Aggie Creek meteorite was lifted by a gold dredge in 1942. From its original location, 15 miles east of Council on the Seward Peninsula, it was taken to Nome by Eskil Anderson and sent on to the University of Alaska Museum. The listed donor is F. K. Dent.

The meteorite is about 90% iron and 8.5% nickel, a composition typical of iron meteorites. Six other meteorites found elsewhere in the world share the exact same composition. That identity has led to the suggestion that the seven objects may be fragments of one original cosmic mass, parts of which have fallen at different places and times.

Proof that the Aggie Creek object truly is a meteorite comes from the pattern exhibited by its cut faces. This is called the Widmanstatten pattern after the man who discovered its existence in iron meteorites. The pattern appears when the polished cut face is treated with acid. The acid etches away most easily one of two minerals the meteorite is composed of (kamacite and taenite) and reveals that the meteorite is a particular laminated structure called an octahedrite.

This octahedral structure is thought to have developed when the meteoritic material first solidified deep within a parent body, now broken up and scattered through the reaches of the solar system. Within our earthbound laboratories, it has not been possible, so far, to exactly duplicate the Widmanstatten pattern--another among many indicators that there is much we have yet to learn.