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The composition of Martian aeolian sands: Thermal emissivity from Viking IRTM observationsAeolian sands provide excellent surfaces for the remote determination of the mineralogic composition of Martian materials, because such deposits consist of relatively well-sorted, uniform particle sizes and might consist of chemically unaltered, primary mineral grains derived from bedrock. Dark features on the floors of Martian craters are controlled by aeolian processes and many consist largely of unconsolidated, windblown sand. Measurement of the thermal emissivity of geologic materials provides a way to identify mid-infrared absorption bands, the strength and positions of which vary with mineral structure and composition. The Viking Infrared Thermal Mapper (IRTM) had four surface-sensing mid-IR bands, three of which, the 7, 9, and 11 micron channels, correspond to absorption features characteristic of carbonates, sialic, and mafic minerals, respectively. In this study, the highest quality IRTM data were constrained so as to avoid the effects of atmospheric dust, clouds, surface frosts, and particle size variations (the latter using data obtained between 7 and 9 H, and they were selected for dark intracrater features such that only data taken directly from the dark feature were used, so as to avoid thermal contributions from adjacent but unrelated materials. Three-point emissivity spectra of Martian dart intracrater features were compared with laboratory emission spectra of minerals and terrestrial aeolian sands convolved using the IRTM response function to the four IRTM spectral channels.
Document ID
19920019767
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Edgett, Kenneth S.
(Arizona State Univ. Tempe, AZ, United States)
Christensen, Philip R.
(Arizona State Univ. Tempe, AZ, United States)
Date Acquired
September 6, 2013
Publication Date
January 1, 1992
Publication Information
Publication: Lunar and Planetary Inst., Workshop on the Martian Surface and Atmosphere Through Time
Subject Category
Lunar And Planetary Exploration
Accession Number
92N29010
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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