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dc.contributor.authorCloutis, Edward A
dc.contributor.authorBell, James F. III
dc.date.accessioned2018-03-07T16:15:13Z
dc.date.available2018-03-07T16:15:13Z
dc.date.issued2000-03-25
dc.identifier.citationCloutis, E.A., and J.F. Bell III. "Diaspores and related hydroxides: Spectral-compositional properties and implications for Mars." Journal of Geophysical Research 105 (2000): 7053-7070.en_US
dc.identifier.issn0148-0227
dc.identifier.urihttp://hdl.handle.net/10680/1396
dc.description.abstractDifferences in spectral reflectance properties (0.3-26 μm) of a suite of metal hydroxides (gibbsite, böhmite, diaspore, goethite, and manganite) have been found to be a function of both structural and compositional differences between these minerals. The properties of the O-H stretching fundamental bands in particular can be used to identify the presence of these minerals and to discriminate isostructural and heteromorphous species. This is due to the fact that the O-H stretching fundamental bands are very intense in these minerals and occur at longer wavelengths than those of other minerals, and also due to the fact that these metal hydroxides lack strong absorption bands at shorter wavelengths. In the case of dimorphous minerals such as böhmite (ϒ-A1O(OH)) and diaspore (α-A1O(OH)), differences in the wavelength positions of O-H stretching fundamental bands can be of the order of 0.1-0.3 μm. Reflectance spectra of metal hydroxide-bearing "ores" (bauxites) and impure samples indicate that accessory phases, in particular iron-bearing minerals, have a more pronounced eftect on spectral reflectance toward shorter wavelengths. Intimate mixtures of diaspore + orthopyroxene indicate that diaspore abundances as low as 5 wt% (or less) can be detected by the appearance of characteristic absorption bands at 3.33 and 3.41μm . This finding has particular relevance to the study of near-infrared spectra of Mars, in that the conditions which favor diaspore formation on the Earth may have also been prevalent early in Mars' history. If diaspore did form on Mars in the past, it is likely to have persisted to the present.en_US
dc.description.sponsorshipThis study was supported by the University of Winnipeg through a start-up grant and research grant through the Discretionary Grants Program (to E.A.C.) and a NASA Planetary Geology and Geophysics Program grant (to J.F.B.; NAG5-4333
dc.description.sponsorshipThis study was supported by the University of Winnipeg through a start-up grant and research grant through the Discretionary 'Grants Program (to E.A.C.) and a NASA Planetary Geology and Geophysics Program grant (to J.F.B.; NAG5-4333
dc.language.isoenen_US
dc.publisherJournal of Geophysical Researchen_US
dc.rightsinfo:eu-repo/semantics/openAccess
dc.titleDiaspores and related hydroxides' Spectral-compositional properties and implications for Marsen_US
dc.typeArticleen_US


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