Mineralogy and Fe-57 Mossbauer spectroscopy of opaque phases in the Neuschwanstein EL6 chondrite
Meteoritics & Planetary Science 39(10): 1643-1648
This study presents compositional data and Fe-57 Mossbauer spectra, taken at 295 K and 85 K, of two fragments of the enstatite (EL6) chondrite Neuschwanstein that fell near the famous Neuschwanstein castle (Bavaria, southern Germany) on April 6, 2002. Main silicate minerals are enstatite (Fs 2) and plagioclase (An 20), the main opaque minerals are kamacite and troilite. Small amounts of oldhamite, daubreelite, and schreibersite have been found. The presented Mossbauer data are the first data gathered for an EL6 chondrite. The dominant parts of each Mossbauer spectrum consist of two six-line patterns due to the presence of ferromagnetic phases kamacite and troilite. In contrast to other chondrites, peaks of other iron species in the central parts of the spectra are missing due to an extremely low content of Fe-bearing paramagnetic components. The hyperfine interaction parameters for kamacite are internal magnetic hyperfine field H-hf = 333.2 kOe, isomer shift (relative to a metallic Fe foil) IS = 0.01 mm/s, quadrupole splitting QS 0 mm/s, line width W = 0.41 mm/s. The data for troilite are H-hf = 305.5 kOe, IS = 0.75 mm/s, QS -0.85 mm/s, W = 0.34 mm/s.