Detection of Mg spinel lithologies on central peak of crater Theophilus using Moon Mineralogy Mapper (M3) data from Chandrayaan-1

Abstract

Spectral reflectance data derived from Moon Mineralogy Mapper (M 3) onboard India's Chandrayaan-1 has revealed Fe bearing Mg-spinel-rich lithology on central peaks of the crater Theophilus. These newly identified Fe bearing Mg-spinel-rich rock types are defined by their strong 2-μm absorption and lack of 1-μm absorptions in spectral reflectance response. Such lithology has been reported previously along the inner ring of Moscoviense Basin on the lunar far side. The Modified Gaussian Modeling (MGM) analysis of the Fe bearing Mg-spinel reflectance spectra has been done and the results of the analysis clearly bring out a strong spectral absorption at 1872 nm with no significant absortion around 1000 nm. The presence of spinel group of minerals in the Theophilus central peak and the fact that central peaks mostly represent uplifted mass of deep crustal material confirm that central peaks can be used as a window to study the deep crustal and/or upper mantle composition and may lead to a fresh perspective about the crustal composition of Moon.

Origin of the lunar highlands Mg-suite: An integrated petrology, geochemistry, chronology, and remote sensing perspective

“…The Mg-rich lithologies seen at both Moscoviense and Theophilus (Fig. 15) occur as discrete small areas, all within a highly feldspathic matrix Dhingra et al 2011;Lal et al 2012). Furthermore, at the best scale currently available (~140 m), no two mafic crustal lithologies discussed here have yet been detected in a contiguous manner to suggest layering.…”

“…Recently, using data from the Moon Mineralogy Mapper (M 3 )-a high spatial and spectral resolution imaging spectrometer on India's Chandrayaan-1 ) was used to characterize the lunar-wide distribution of low-Ca pyroxenes (Klima et al 2011b), olivine , and Mg-spinel Lal et al 2012). The high spectral resolution of the M 3 instrument (20-40 nm depending on the wavelength range, see Green et al 2011) allows for detailed MGM analysis with uncertainties in band centers of ±10 nm for the 1 mm absorption feature and ±20-50 nm for the 2 mm band.…”

Compositional diversity of near-, far-side transitory zone around Naonobu, Webb and Sinus Successus craters: Inferences from Chandrayaan-1 Moon Mineralogy Mapper (M3) data

“…In this light, the hyperspectral payload, M 3 , onboard Chandrayaan-1 mission has shed some critical information on large scale mineralogical-and lithologicalvariations that could not be unraveled by earlier lunar orbiters (Taylor 1982;Demidova et al 2007;Isaacson et al 2011). One such observation is the discovery of spinel-rich deposits on the lunar surface (Pieters et al 2009(Pieters et al , 2010Dhingra et al 2011;Lal et al 2012). Identification of several such areas on the rim of Moscoviense basin indicates that Mg-Al spinel rich areas contain less than 5% mafic silicate minerals (olivine and pyroxene).…”

Active moon: evidences from Chandrayaan-1 and the proposed Indian missions

“…The M 3 data with high spectral resolution and wide spectral coverage identified sites showing Mg-spinel anorthosite (devoid of olivines and pyroxenes and having FeO < 5 wt%) along the rings of Moscoviense basin on the far side of the Moon [54]. These were also found in the central peak of Theophilus crater along the ring of Nectaris basin [55,56].…”