HR: 0800h
AN: P21A-0217    [Abstracts]
TI: Target Transformation and Factor Analysis of Mini-TES Spectra and Comparison to TES and Laboratory Hematite Spectra
AU: * Glotch, T D
EM: tglotch@asu.edu
AF: Arizona State University, Department of Geological Sciences, Tempe, AZ 85287-6305
AU: Bandfield, J L
EM: joshband@asu.edu
AF: Arizona State University, Department of Geological Sciences, Tempe, AZ 85287-6305
AU: Christensen, P R
EM: phil.christensen@asu.edu
AF: Arizona State University, Department of Geological Sciences, Tempe, AZ 85287-6305
AB: A main objective of sending the MER Opportunity rover to Meridiani Planum was to investigate the occurrence of gray, crystalline hematite detected by the Mars Global Surveyor Thermal Emission Spectrometer (MGS-TES) instrument. Among the instruments on the rover payload is the Mini-TES instrument, which serves as a complement to the orbital TES instrument and mid-infrared laboratory studies of hematite. The characteristic mid-infrared hematite spectrum contains strong absorptions at ~300, 450, and 540 cm$^{-1}$. An additional minor absorption is sometimes present at 390 cm$^{-1}$. The exact position, shape and relative strengths of these absorptions vary depending on the hematite formation process. The gray hematite at Meridiani Planum is present in the form of spherules that have been interpreted as concretions weathering out of a sulfate-rich outcrop. The spherules are also abundant on the plains of Meridiani and may be present as a lag. The shapes of the hematite features in Mini-TES spectra have not varied substantially despite many rock and soil observations made over the course of the mission, implying that the spherules have a uniform composition. Although neither the TES nor the Mini-TES instrument covers the full wavelength range over which the hematite spectral features are seen, the hematite spectra from both instruments are broadly similar. The TES and Mini-TES hematite spectra are matched best by a laboratory spectrum of a hematite sample that was produced by dehydroxylating goethite at $300\deg$C. However, there are some small differences between the Mini-TES hematite spectra and hematite spectra from MGS-TES and laboratory measurements that may yield some new insight into the hematite formation process. Target transformation and factor analysis techniques will be applied to Mini-TES spectra to isolate the various components, including hematite, to provide the best possible comparison.
DE: 5410 Composition
DE: 5464 Remote sensing
DE: 6207 Comparative planetology
DE: 6225 Mars
DE: 6297 Instruments and techniques
SC: Planetary Sciences [P]
MN: 2004 AGU Fall Meeting