Moon: Near‐infrared spectral reflectance, A first good look

Abstract

A positive identification of the minerals olivine, plagioclase, and several types of pyroxenes were made at several locations on the lunar surface by using remote measurements. For example, the crater Aristarchus is found to have an average pyroxene composition of augite, and plagioclase is obviously present. A dark mantle deposit in the crater J. Herschel is at least partly composed of a mixture of 70% olivine and 30% pyroxene. These determinations were possible because the reflectance spectra for 10–20 km diameter lunar areas have been measured for the first time in the IR spectral region (0.65–2.5 μm) with sufficient spectral resolution and photometric precision to define mineral electronic absorption bands. The reflectance for all lunar regions observed (over 100 to present) continues to increase toward longer wavelengths to at least 2.5 μm, and several mineral absorption bands appear. The telescopic spectra are of similar quality and contain features similar to laboratory spectra of lunar samples. The absorption features in several spectra have been quantitatively analyzed using newly developed computer processing techniques, including thermal flux removal and absorption band fitting, to produce these mineral identifications. Detection and quantitative analysis of these absorptions provide a much improved basis for remotely determining and mapping surface mineralogy quantitatively from the ground or using airborne or spacecraft platforms.

Tohoku-Hiroshima-Nagoya planetary spectra library: a method for characterizing planets in the visible to near infrared

“…1. This spectrum is similar to infrared crater spectra obtained by other researchers (McCord 1981). The spectrum drops sharply below the other soil planets in the visible and stays flat thoughout the infrared.…”

“…To find spectral libraries in many cases it is necessary to return to the 1970's and early 1980's when the first quality spectra of planets were being obtained. Particularly prolific studies during this era were, e.g., McCord & Westphal (1971), Fink et al (1976), McCord et al (1979), Fink & Larson (1979), Clark (1980, 1981), and McCord (1981. However, this was also a time of rapid technological development and even within a single research group, observational techniques changed.…”

Remote sensing and geological studies of the Hadley‐Apennine region of the Moon

“…Standard observing techniques and data reduction procedures were employed (McCord et al,198 1). The telescopic observation and data reduction procedures are such that absolute brightness information is not preserved, and the resulting spectra are inherently scaled to a value of 1 .O at a reference wavelength (McCord et al, 1981). This contrasts with the Clementine data, which can be calibrated to absolute reflectance (e.g., Pieters et al, 1994;Hillier et al, 1999).…”

Remote sensing studies of the terrain northwest of Humorum Basin

“…These relative spectra were converted to absolute reflectance utilizing thercflectancecurveof an Apollo 16 soil sample. Analyses of mafic band positions and shapes as well as continuum slopes were made using the techniques described by McCord et al [1981]. The locations and lithologie classification of the spectral data appear in Figure 1, and representative spectra are shown in Figures 2 and 3, the various observations and (2) the lack of thermal corrections in the 2.0-2.5 \un spectral region, (b) Reflectance spectra after continuum removal (straight line estimated for a 1 Jim absorption feature).…”