The strange iron silicide matter from the Chiemgau meteorite impact strewn field at the 42nd Lunar and Planetary Science Conference (LPSC), March 7-11, 2011, The Woodlands, Texas, USA:
SEM and TEM analyses of minerals xifengite, gupeiite, Fe2Si (hapkeite ?), titanium carbide (TiC) and cubic moissanite (SiC) from the subsoil in the Alpine Foreland: Are they cosmochemical?
M. Hiltl1, F. Bauer2, K. Ernstson3, W. Mayer4, A. Neumair4, and M.A. Rappenglück4
1Carl Zeiss Nano Technology Systems GmbH, Oberkochen, Germany, 2Oxford Instruments GmbH NanoScience, Wiesbaden, Germany, 3University of Würzburg, Germany, 4Institute for Interdisciplinary Studies, Gilching, Germany
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Abstract article Fig. 1: Typical example of the investigated iron silicide particles. Note the slightly regmaglyptic surface (regmaglypts) of the particle reminding of the characteristic surface of many meteorites.
Abstract article Fig. 2: SEM image of perfect moissanite (SiC) crystals out-growing from the iron silicide (mostly xifengite, gupeiite) matrix.
It is interesting to note that the silicon carbide moissanite (SiC) has been reported to occur together with diamond lonsdaleite in impact melt rock from the Ries impact crater:
R. M. HOUGH, I. GILMOUR, C. T. PILLINGER, J. W. ARDEN, K. W. R. GILKESS, J. YUAN & H. J. MILLEDGE (1995): Diamond and silicon carbide in impact melt rock from the Ries impact crater. – Nature, 378, 41-44.
The authors suggest that the minerals formed by chemical vapour deposition from the ejecta plume in the impact event and hence may be used as a reliable diagnostic tool for hypervelocity impact on Earth.
Abstract article Fig. 3: Titanium carbide (TiC) crystal in a matrix of iron silicides; 1: FeSi, 2: Fe3Si (gupeiite), 3: Fe5Si3 (xifengite).
Abstract article Fig. 4: Surface of an iron silicide particle that exhibits rimmed craters suggesting impacts from micrometer- sized projectiles.