Thermal infrared and Raman microspectroscopy of moganite-bearing rocks

Craig Hardgrove, A. Deanne Rogers

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

We present the first thermal infrared reflectance spectral characterization of moganite and mixtures of moganite with microcrystalline quartz. We find that for relatively high (>50%) abundances of moganite, the absolute reflectance for samples is significantly reduced. Using microscopic-Raman (∼1 μm/pixel) measurements, we estimate the moganite content for various samples. We then compare Raman-derived moganite abundances with microscopic infrared reflectance (25 μm/pixel) spectra to determine the effects of increasing moganite abundance on thermal infrared spectra. We find that moganite is broadly spectrally similar to quartz with major reflectance maxima located between ∼1030 and 1280 cm-1 and ∼400 and 600 cm-1; but there are characteristic differences in the peak shapes, peak center positions, and especially the relative peak reflectance magnitudes. For regions with high (>50%) moganite content, the relative magntitudes of the reflectance maxima at 1157 and 1095 cm-1 (R1095/R1157 band ratio) can be used to estimate the moganite content. This work demonstrates the utility of thermal infrared microspectroscopy in isolating phases that are intimately mixed in a sample, and has applications in planetary science, where constituent phases of quartz-rich sedimentary rocks can be identified using remote or in situ thermal infrared spectroscopy.

Original languageEnglish (US)
Pages (from-to)78-84
Number of pages7
JournalAmerican Mineralogist
Volume98
Issue number1
DOIs
StatePublished - Jan 2013
Externally publishedYes

Fingerprint

Bearings (structural)
reflectance
Rocks
rocks
Infrared radiation
Quartz
rock
quartz
pixel
pixels
Pixels
spectral reflectance
sedimentary rocks
Sedimentary rocks
estimates
infrared spectroscopy
sedimentary rock
infrared spectra
Hot Temperature
Infrared spectroscopy

Keywords

  • Chert
  • Infrared spectroscopy
  • Mars
  • Microcrystalline quartz
  • Microspectroscopy
  • Moganite
  • Raman spectroscopy
  • Silica

ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Geophysics

Cite this

Thermal infrared and Raman microspectroscopy of moganite-bearing rocks. / Hardgrove, Craig; Rogers, A. Deanne.

In: American Mineralogist, Vol. 98, No. 1, 01.2013, p. 78-84.

Research output: Contribution to journalArticle

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