Portales Valley: A meteoritic sample of the brecciated and metal-veined floor of an impact crater on an H-chondrite asteroid

Abstract

A shower of meteorite fragments fell at ~0730 h local time on 1998 June 13 near the town of Portales, New Mexico. Thus far, 51 pieces of the Portales Valley (H6) meteorite have been recovered. This meteorite has an unusually large number of metallic veins. Some of these veins are also unusually thick, having widths on the order of centimeters. These wide veins have fine Widmanstatten structure, which is the first time it has been seen in an ordinary chondrite. This structure indicates the metallic veins and the host chondrite cooled slowly. These veins appear to have been produced by shock-metamorphic processes, which we infer produced a >20 km diameter impact crater on an H-chondrite planetesimal.