Mid-Infrared Reflectance Spectra of Lunar Soils: Christiansen Frequency Correlations with Composition
Abstract
As part of a broad study to characterize the mid-IR reflectance properties of lunar samples, we have taken mid-IR FTIR reflectance spectra of several soil samples from all six Apollo sites. We have compared the location of the Christiansen frequency (CF) (reflectance minimum) with indicators of bulk composition. For lunar soils, we find a loose, but significant, correlation between the CF (a spectroscopic parameter) and the SCFM index (parameter indicative of bulk mineral content: SiO2/(SiO2 + CaO + FeO + MgO)). There is much less, if any, correlation between CF position and SiO2 percent alone. We also see groupings in a plot of CF vs SCFM that correlate with mission in some cases (particularly for the less mafic Apollo 14 and 16 soils), and in the case of Apollo 17, that correlate with different geologic units. Thus, use of the CF in thermal emission spectroscopy holds promise for general mineralogic and geologic characterization of the lunar and perhaps Mercurian surfaces, but clear distinctions can only be made when comparing significantly different CF values.
- Publication:
-
Lunar and Planetary Science Conference
- Pub Date:
- March 1997
- Bibcode:
- 1997LPI....28..107B
- Keywords:
-
- Lunar Probes;
- Spectral Reflectance;
- Lunar Composition;
- Apollo Flights;
- Lunar Soil;
- Infrared Spectra;
- Minerals;
- Lunar Geology;
- Frequency Response;
- Lunar and Planetary Exploration;
- CHRISTIANSEN FREQUENCY;
- INFRARED;
- MOON;
- SOIL: LUNAR;
- SPECTROSCOPY