ICATE   21876
INSTITUTO DE CIENCIAS ASTRONOMICAS, DE LA TIERRA Y DEL ESPACIO
Unidad Ejecutora - UE
artículos
Título:
Druse clinopyroxene in DOrbigny angritic meteorite studied by single-crystal
Autor/es:
ABDU, Y.; SCORZELLI R,; VARELA, M.E; KURAT G,; SOUZA AZEVEDO, I.; STEWART S,; HAWTHORNE F.
Revista:
METEORITICS & PLANETARY SCIENCE
Editorial:
METEORITICAL SOC
Referencias:
Año: 2009 vol. 44 p. 581 - 587
ISSN:
1086-9379
Resumen:
AbstractThe crystal structure of druse clinopyroxene from the DOrbigny angrite, (Ca0.944 Fe2+
AbstractThe crystal structure of druse clinopyroxene from the DOrbigny angrite, (Ca0.944 Fe2+The crystal structure of druse clinopyroxene from the DOrbigny angrite, (Ca0.944 Fe2+
0.042
Mg0.010Mn0.004) (Mg0.469Fe2+0.010Mn0.004) (Mg0.469Fe2+
0.317Fe3+Fe3+
0.035Al0.125Cr0.010Ti0.044) (Si1.742Al0.258) O6, a = 9.7684(2), b =Al0.125Cr0.010Ti0.044) (Si1.742Al0.258) O6, a = 9.7684(2), b =
8.9124(2), c = 5.2859(1) Å, β = 105.903(1)°, V = 442.58 Å3, space group C2/c, Z = 2, has been refined
to an R1 index of 1.92% using single-crystal X-ray diffraction data. The unit formula, calculated from
electron microprobe analysis, and the refined site scattering values were used to assign site
populations. The distribution of Fe2+ and Mg over the M1 and M2 sites suggests a closure temperature
of 1000 °C. Mössbauer spectroscopy measurements were done at room temperature on a single
crystal and a powdered sample. The spectra are adequately fit by a Voigt-based quadrupole-splitting
distribution model having two generalized sites, one for Fe2+ with two Gaussian components and one
for Fe3+ with one Gaussian component. The two ferrous components are assigned to Fe2+ at the M1
site, and arise from two different next-nearest-neighbor configurations of Ca and Fe cations at the M2
site: (3Ca,0Fe) and (2Ca,1Fe). The Fe3+/Fetot ratio determined by Mössbauer spectroscopy is in
agreement with that calculated from the electron microprobe analysis. The results are discussed in
connection with the redox and thermal history of DOrbignc = 5.2859(1) Å, β = 105.903(1)°, V = 442.58 Å3, space group C2/c, Z = 2, has been refined
to an R1 index of 1.92% using single-crystal X-ray diffraction data. The unit formula, calculated from
electron microprobe analysis, and the refined site scattering values were used to assign site
populations. The distribution of Fe2+ and Mg over the M1 and M2 sites suggests a closure temperature
of 1000 °C. Mössbauer spectroscopy measurements were done at room temperature on a single
crystal and a powdered sample. The spectra are adequately fit by a Voigt-based quadrupole-splitting
distribution model having two generalized sites, one for Fe2+ with two Gaussian components and one
for Fe3+ with one Gaussian component. The two ferrous components are assigned to Fe2+ at the M1
site, and arise from two different next-nearest-neighbor configurations of Ca and Fe cations at the M2
site: (3Ca,0Fe) and (2Ca,1Fe). The Fe3+/Fetot ratio determined by Mössbauer spectroscopy is in
agreement with that calculated from the electron microprobe analysis. The results are discussed in
connection with the redox and thermal history of DOrbign1 index of 1.92% using single-crystal X-ray diffraction data. The unit formula, calculated from
electron microprobe analysis, and the refined site scattering values were used to assign site
populations. The distribution of Fe2+ and Mg over the M1 and M2 sites suggests a closure temperature
of 1000 °C. Mössbauer spectroscopy measurements were done at room temperature on a single
crystal and a powdered sample. The spectra are adequately fit by a Voigt-based quadrupole-splitting
distribution model having two generalized sites, one for Fe2+ with two Gaussian components and one
for Fe3+ with one Gaussian component. The two ferrous components are assigned to Fe2+ at the M1
site, and arise from two different next-nearest-neighbor configurations of Ca and Fe cations at the M2
site: (3Ca,0Fe) and (2Ca,1Fe). The Fe3+/Fetot ratio determined by Mössbauer spectroscopy is in
agreement with that calculated from the electron microprobe analysis. The results are discussed in
connection with the redox and thermal history of DOrbign2+ and Mg over the M1 and M2 sites suggests a closure temperature
of 1000 °C. Mössbauer spectroscopy measurements were done at room temperature on a single
crystal and a powdered sample. The spectra are adequately fit by a Voigt-based quadrupole-splitting
distribution model having two generalized sites, one for Fe2+ with two Gaussian components and one
for Fe3+ with one Gaussian component. The two ferrous components are assigned to Fe2+ at the M1
site, and arise from two different next-nearest-neighbor configurations of Ca and Fe cations at the M2
site: (3Ca,0Fe) and (2Ca,1Fe). The Fe3+/Fetot ratio determined by Mössbauer spectroscopy is in
agreement with that calculated from the electron microprobe analysis. The results are discussed in
connection with the redox and thermal history of DOrbign°C. Mössbauer spectroscopy measurements were done at room temperature on a single
crystal and a powdered sample. The spectra are adequately fit by a Voigt-based quadrupole-splitting
distribution model having two generalized sites, one for Fe2+ with two Gaussian components and one
for Fe3+ with one Gaussian component. The two ferrous components are assigned to Fe2+ at the M1
site, and arise from two different next-nearest-neighbor configurations of Ca and Fe cations at the M2
site: (3Ca,0Fe) and (2Ca,1Fe). The Fe3+/Fetot ratio determined by Mössbauer spectroscopy is in
agreement with that calculated from the electron microprobe analysis. The results are discussed in
connection with the redox and thermal history of DOrbign2+ with two Gaussian components and one
for Fe3+ with one Gaussian component. The two ferrous components are assigned to Fe2+ at the M1
site, and arise from two different next-nearest-neighbor configurations of Ca and Fe cations at the M2
site: (3Ca,0Fe) and (2Ca,1Fe). The Fe3+/Fetot ratio determined by Mössbauer spectroscopy is in
agreement with that calculated from the electron microprobe analysis. The results are discussed in
connection with the redox and thermal history of DOrbign3+ with one Gaussian component. The two ferrous components are assigned to Fe2+ at the M1
site, and arise from two different next-nearest-neighbor configurations of Ca and Fe cations at the M2
site: (3Ca,0Fe) and (2Ca,1Fe). The Fe3+/Fetot ratio determined by Mössbauer spectroscopy is in
agreement with that calculated from the electron microprobe analysis. The results are discussed in
connection with the redox and thermal history of DOrbign3+/Fetot ratio determined by Mössbauer spectroscopy is in
agreement with that calculated from the electron microprobe analysis. The results are discussed in
connection with the redox and thermal history of DOrbign