Detection and discrimination of sulfate minerals using reflectance spectroscopy

Edward A. Cloutis, Frank C. Hawthorne, Stanley A. Mertzman, Katherine Krenn, Michael A. Craig, Dionne Marcino, Michelle Methot, Johnathon Strong, John F. Mustard, Diana L. Blaney, James F. Bell, Faith Vilas

Research output: Contribution to journalArticle

221 Scopus citations

Abstract

A suite of sulfate minerals were characterized spectrally, compositionally, and structurally in order to develop spectral reflectance-compositional-structural relations for this group of minerals. Sulfates exhibit diverse spectral properties, and absorption-band assignments have been developed for the 0.3-26 μm range. Sulfate absorption features can be related to the presence of transition elements, OH, H2O, and SO4 groups. The number, wavelength position, and intensity of these bands are a function of both composition and structure. Cation substitutions can affect the wavelength positions of all major absorption bands. Hydroxo-bridged Fe3+ results in absorption bands in the 0.43, 0.5, and 0.9 μm regions, while the presence of Fe2+ results in absorption features in the 0.9-1.2 μm interval. Fundamental S{single bond}O bending and stretching vibration absorption bands occur in the 8-10, 13-18, and 19-24 μm regions (1000-1250, 550-770, and 420-530 cm-1). The most intense combinations and overtones of these fundamentals are found in the 4-5 μm (2000-2500 cm-1) region. Absorption features seen in the 1.7-1.85 μm interval are attributable to H{single bond}O{single bond}H/O{single bond}H bending and translation/rotation combinations, while bands in the 2.1-2.7 μm regions can be attributed to H2O- and OH-combinations as well as overtones of S{single bond}O bending fundamentals. OH- and H2O-bearing sulfate spectra are fundamentally different from each other at wavelengths below ∼6 μm. Changes in H2O/OH content can shift S{single bond}O band positions due to change in bond lengths and structural rearrangement. Differences in absorption band wavelength positions enable discrimination of all the sulfate minerals used in this study in a number of wavelength intervals. Of the major absorption band regions, the 4-5 μm region seems best for identifying and discriminating sulfates in the presence of other major rock-forming minerals.

Original languageEnglish (US)
Pages (from-to)121-157
Number of pages37
JournalIcarus
Volume184
Issue number1
DOIs
StatePublished - Sep 1 2006
Externally publishedYes

Keywords

  • Asteroids
  • Europa
  • Mars
  • Meteorites
  • Mineralogy
  • Spectroscopy
  • composition
  • surface

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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  • Cite this

    Cloutis, E. A., Hawthorne, F. C., Mertzman, S. A., Krenn, K., Craig, M. A., Marcino, D., Methot, M., Strong, J., Mustard, J. F., Blaney, D. L., Bell, J. F., & Vilas, F. (2006). Detection and discrimination of sulfate minerals using reflectance spectroscopy. Icarus, 184(1), 121-157. https://doi.org/10.1016/j.icarus.2006.04.003