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Sulfates on Mars: A systematic Raman spectroscopic study of hydration states of magnesium sulfates

Geochimica et Cosmochimica Acta

By:
, , , and
DOI: 10.1016/j.gca.2006.05.022

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Abstract

The martian orbital and landed surface missions, OMEGA on Mar Express and the two Mars Explorations Rovers, respectively, have yielded evidence pointing to the presence of magnesium sulfates on the martian surface. In situ identification of the hydration states of magnesium sulfates, as well as the hydration states of other Ca- and Fe- sulfates, will be crucial in future landed missions on Mars in order to advance our knowledge of the hydrologic history of Mars as well as the potential for hosting life on Mars. Raman spectroscopy is a technique well-suited for landed missions on the martian surface. In this paper, we report a systematic study of the Raman spectra of the hydrates of magnesium sulfate. Characteristic and distinct Raman spectral patterns were observed for each of the 11 distinct hydrates of magnesium sulfates, crystalline and non-crystalline. The unique Raman spectral features along with the general tendency of the shift of the position of the sulfate ??1 band towards higher wavenumbers with a decrease in the degree of hydration allow in situ identification of these hydrated magnesium sulfates from the raw Raman spectra of mixtures. Using these Raman spectral features, we have started the study of the stability field of hydrated magnesium sulfates and the pathways of their transformations at various temperature and relative humidity conditions. In particular we report on the Raman spectrum of an amorphous hydrate of magnesium sulfate (MgSO4??2H2O) that may have specific relevance for the martian surface. ?? 2006 Elsevier Inc. All rights reserved.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Sulfates on Mars: A systematic Raman spectroscopic study of hydration states of magnesium sulfates
Series title:
Geochimica et Cosmochimica Acta
DOI:
10.1016/j.gca.2006.05.022
Volume
70
Issue:
24
Year Published:
2006
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Geochimica et Cosmochimica Acta
First page:
6118
Last page:
6135
Number of Pages:
18