Mineralogy, geochemistry and classification of the new Smolenice iron meteorite from Slovakia

Abstract

A single 13.95 kg mass of a slightly weathered iron meteorite was found in the forest near Smolenice (48°31.2’N, 17°23.9’E; Trnava County, Slovakia). The bulk chemical composition (in wt. %) is: Fe 88.78, Ni 8.16, Co 0.38, P 0.05, S<0.006 and (in μg/g): Ge<0.18, Ir 1.67, Ga 1.80, Cr 87.3, Cu 135.1, As 4.52, Mo 5.82, Sn 1.53, W 0.56, Re 0.18, Ru 3.56, Rh 0.90, Pd 4.12, Pt 5.35, Au 1.19, Zn<5, B<0.68, Pb<0.06. Bulk geochemistry, and Ni, Ga, Ge and Ir contents in particular suggest that the meteorite is an octahedrite belonging to the IVA group. The average thickness of kamacite lamellae is 0.22 mm, ranking it as fine octahedrite (Of). The mineral composition is simple, the most abundant minerals being iron (kamacite) (5.16–7.36 wt. % Ni) followed by taenite (16.73–33.93 wt. % Ni). Troilite nodules and daubréelite inclusions and thin veinlets are rare. The Widmanstätten pattern is uniform across the meteorite and plessite structure is developed locally. Analyses of cosmogenic radionuclides (14C and 26Al) indicate that the radius of the Smolenice meteorite could be 30±10 cm and its terrestrial age 11±2 kyr.