The Getafe rock: Fall, composition and cosmic ray records of an unusual ultrarefractory scoriaceous material

In 1994 a moving car and its driver, on a highway in southern Madrid (Getaf e), were struck by a falling rock. Eighty-one additional fragments (total w eight : 55.926 kg) were later recovered, which all pointed towards a meteor ite fall. A study of the composition of this object revealed an ultrarefrac tory material displaying a most unusual chemical make up which differs from any known meteorite class, and For some elements and minerals approaches t he composition of CAI (Ca-Al-rich inclusions in chondrites). A. study of so me cosmic-ray-produced stable and radioactive nuclides indicates: a) space and terrestrial exposure ages which do not exceed 1,000 and 520,000 years, respectively; b) the presence of a small Ne-22 excess (1,100 degrees C frac tion), which suggests either a nucleogenic contribution from the F-19(alpha ,n)Ne-22 reaction or a trapped Ne signature distinct from atmospheric Ne, a nd c) the existence of minor variations in the Ar-38/Ar-36 ratios also indi cating a nucleogenic component or fractionation effects. C-14 data are cons istent with "modern" carbon originated in the period 1955-1958 and not earl ier or more recently. The possibility that the Getafe rock could have a man -made origin (i.e, ceramic and refractory tiles, industrial slag) is also c onsidered.