THE LUEDERS, TEXAS, IAB IRON METEORITE WITH SILICATE INCLUSIONS

The Lueders iron meteorite with silicate inclusions was recovered as a single specimen of similar to 35.4 kg in Shackelford County, Texas, i n 1973 and recognized as a meteorite in 1993. Siderophile element conc entrations indicate chemical classification as a low-Ni IAB iron meteo rite closely related to Landes; like Landes, it has a Cu content simil ar to 4 sigma above the main IAB-IIICD trend and therefore we also des ignate Lueders as an anomalous member of IAB. The metallic host is com posed of equigranular kamacite but with a suggestion of octahedral str ucture and with a bandwidth of 1.4 mm, suggesting structural classific ation as a coarse octahedrite (Og). The meteorite contains similar to 23 wt% of roughly millimeter to centimeter-sized angular silicate incl usions. Classification as a IAB is confirmed by O isotopic analysis of silicate inclusions. These inclusions contain an assemblage rich in s ilicates, troilite and graphite; lack certain minor phases (e.g., daub reelite); and have angular shapes. A variety of processes (e.g., fragm entation, partial melting, reduction) appear to have played a signific ant role in the formation of Lueders and all IAB iron meteorites. Petr ologic and chemical differences confirm that Lueders is not paired wit h the widely distributed Odessa meteorite.