Raman study of EETA79001 Martian meteorite
Compositional features of olivine, pyroxene, and opaque minerals
A. Studied rock chips -- Raman point-counting measurements were made on unprepared surfaces of the rock chips with surface relief on the order of several mm.
B. Major minerals (pyroxene and olivine) -- The continuous range of Mg' in all rock chips indicates that the pyroxenes are mainly rapidly cooled, unequilibrated pyroxenes typical of basalt; the histogram for 79001,482 pyroxenes spans a broader range, however, and extends to more Fe-rich composi-tions, indicating more rapid crystallization. Using Raman spectral data published by Guyot et al.  and Chopelas , we developed a correlation to calculate Fo values (Mg/(Mg+Fe) mole fraction) of oli-vine based on the frequencies of their strongest doublet at ~850 cm-1 and ~820 cm-1 (Fig. 1b).
C. Minor and rare mineral phases identified in point-counting procedure
D. Raman features of opaque minerals --how the structural and compositional information of these minerals can be extracted from their Raman spec-tral patterns and peak positions.
The degree of covalency of a chemical bond, A-O, or the compressibility of a polyhedron (indicated by the bulk modulus) in a crystal structure is commonly used to predict the major ionic group responsible for Raman spectral features.In Fe-Ti oxides, however, differences in bond strength between different types of polyhedra are less pronounced. Thus, only approximate "major contribu-tors" for the Raman spectral features can be assigned, and these roles can be changed by cation substitutions. In following Table, the suggested major contributors of Raman features for each oxide are marked in bold typeface.
Reference: Wang A., Kuebler, K.E , Jolliff B. L., Haskin L. A.,
Mineral features of EETA79001 martian meteorite revealed by point-counting Raman
measurements as anticipated for in-situ exploration on planetary surfaces, 31th