Neuschwanstein

Bavaria, Germany

Fell 2002 April 6; 20:20 hrs (UT)

Enstatite chondrite (EL6)

A brilliant fireball, shaking the ground and rattling windows, was reported by many eyewitnesses in Austria and Germany. The fall circumstances were well documented by the European Fireball Network (EFN). Reduction of the EFN photographs allowed calculation of the orbit and impact area (Spurny et al. 2002) which ultimately led to the recovery of a single stone of 1.75 kg on July 14, 2002. Gamma spectrometry (G. Heusser and H. Neder, MPI-K) of the stone indicates a small pre-atmospheric radius of less than 20 cm mainly from the low ⁶⁰Co activity of 1.2 ± 0.5 dpm/kg. Short-lived radionuclides strongly indicate that the recovered meteorite was indeed the object that fell on the above date. Classification and mineralogy (A. Bischoff, Mün and J. Zipfel, MPI): the meteorite has a metamorphic texture with a small number of chondrule relics. Major phases are enstatite (FeO <0.1 wt%), plagioclase (Ab82), and metal (~1.5 wt% Si). Large crystals of sinoite (up to 200 µm) and graphite (up to 700 × 200 µm) are present. Additional phases so far observed are schreibersite ((Fe,Ni)3P), troilite (FeS), oldhamite (CaS), daubreelite (FeCr2S4), alabandite, ((Mn,Fe)S), and an SiO2­ phase (containing 1–2 wt% Al2O3). Bulk chemistry: abundances of moderately volatile lithophile elements are typical for EL chondrites, low Mn/Mg = 0.010 and Na/Mg = 0.045, and low Zn concentration (Zn <20 ppm); high concentrations of siderophile elements, e.g., Ni = 1.94% and Ir = 0.76 ppm, reflect higher than usual metal contents for EL chondrites. Based on texture, mineralogy and chemistry the meteorite is classified as an EL6 chondrite. Optical features indicate that the rock is very weakly shocked (S2). The residence time of about three months on the ground resulted in the first signs of weathering (W0/1). The exposure age is ~48 Ma; trapped subsolar noble gases are present (L. Franke and L. Schultz, MPI). Specimens: type specimen, 20 g, MPI; thin sections: Mün; main mass, unknown.