Mineralogical and spectroscopic investigation of enstatite chondrites by X-ray diffraction and infrared reflectance spectroscopy

Matthew Richar Izawa, P. L. King, R. L. Flemming, R. C. Peterson, P. J A McCausland

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

The mineralogy and infrared reflectance spectra of 13 Enstatite (E) chondrite meteorite finds spanning the full range of textural alteration grades in both EL and EH classes have been investigated. Rietveld refinement of high-resolution powder X-ray diffraction (XRD) data was used to determine quantitative major mineral abundances. Sample-correlated mid-infrared (2.0 to 25.0 m; 4500 cm-1 to 400 cm-1) reflectance infrared spectra were collected for each meteorite. Spectral features due to the fundamental lattice vibrations of the silicates, primarily enstatite, dominate the spectra of these meteorites over most of the spectral range investigated. The spectral features related to primary (i.e., pre-terrestrial) mineralogy include fundamental stretching and bending lattice modes (∼8.3-25.0 m; 1200-400 cm-1), overtones and combinations of the fundamental modes (∼4.5-6.1 m; 2200-1650 cm-1), and the principle Christensen feature (∼8.3 m; 1200 cm-1). Terrestrial weathering products including Fe-oxyhydroxides, gypsum, and carbonates occur in most of these meteorites and contribute to some spectral features: particularly an asymmetric feature near ∼2.6 to 3.8 m (3800 to 2600 cm-1) attributed to adsorbed, hydrogen-bonded, and/or structural OH and H2O, and a feature near ∼6.2 m (1625 cm-1) attributed to adsorbed, hydrogen-bonded, and/or structural H2O. Modal mineral abundances determined by Rietveld refinement have been used to calculate model grain densities for each meteorite. Bulk magnetic susceptibility measurements combined with modal mineralogy and grain densities reveal a trend toward lower grain density and lower bulk susceptibility with increased terrestrial weathering.

Original languageEnglish
Article numberE07008
JournalJournal of Geophysical Research E: Planets
Volume115
Issue number7
DOIs
Publication statusPublished - 2010
Externally publishedYes

Fingerprint

Meteorites
enstatite chondrite
enstatite
chondrites
meteorites
meteorite
reflectance
spectroscopy
X-ray diffraction
Spectroscopy
Mineralogy
Infrared radiation
X ray diffraction
mineralogy
diffraction
Rietveld refinement
weathering
Weathering
x rays
Minerals

ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Geophysics
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science

Cite this

Mineralogical and spectroscopic investigation of enstatite chondrites by X-ray diffraction and infrared reflectance spectroscopy. / Richar Izawa, Matthew; King, P. L.; Flemming, R. L.; Peterson, R. C.; McCausland, P. J A.

In: Journal of Geophysical Research E: Planets, Vol. 115, No. 7, E07008, 2010.

Research output: Contribution to journalArticle

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