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Usti nad Orlici (Kerhartice), a meteorite which fell on June 12, 1963 in Czechoslovakia, is classified as a L6 chondrite. Compositions of olivine (Fa 23.4), orthopyroxene (Fs 20, Wo 1.3), plagioclase (Ab85An10Or5) along with the bulk composition of the meteorite support this classification. Chromite compositions vary with grain size. Large chromites are higher in TiO2 and lower in Fe3 than small chromites. This may indicate that either these two chromites formed initially under different fO2 conditions, or that this difference resulted from different equilibration behaviors of both chromites as a function of grain size. The meteorite contains three distinct sulfide assemblages: 1) troilite-pentlandite, 2) troilite, pentlandite-cubanite-chalcopyrite-pyrrhotite-mackinawite, 3) troilite-tetrataenite-(Fe, Cu, Ni)1***.02S. These assemblages indicate equilibration down to temperatures close to 200 °C. |
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