Nonmare volcanism on the Moon: Photometric evidence for the presence of evolved silicic materials

作者：Clegg Watkins R N^*; Jolliff B L; Watkins M J; Coman E; Giguere T A; Stopar J D; Lawrence S J

来源：Icarus, 2017, 285: 169-184.

DOI：10.1016/j.icarus.2016.12.004

• Moon
• Photometry
• Volcanism
• Moon, surface
• Mineralogy, Spectroscopy

Images and photometric data from the Lunar Reconnaissance Orbiter Camera (LROC) Narrow Angle Cameras (NACs) are used to investigate regions of the Moon inferred from previous remote sensing compositional studies to be associated with nonmare, silicic volcanics. Specifically, LROC NAC imagery, with photometry normalized to account for local slopes using NAC Digital Terrain Models (DTM5), was used to investigate the exposed areas associated with the Compton-Belkovich Volcanic Complex (CBVC), Hansteen Alpha Volcanic Complex (HAVC), Lassell Massif (LM), Gruithuisen Domes (GD), and ejecta of Aristarchus Crater (AC). Photometric studies of spacecraft landing sites, for which ground-truth compositional data exist, allow us to study the relationship between photometric properties of soils and their mineralogical and chemical compositions. The silicic regions have high reflectance and single scattering albedos that are consistent with different proportions of highly reflective minerals including alkali feldspar and quartz, and low concentrations of mafic minerals. Of the silicic sites studied, the CBVC has the highest reflectance values and single scattering albedos. Silicic pyroclastic deposits may also occur at the CBVC, and we present evidence from laboratory spectra that an addition of up to similar to 20 wt% glassy silicic materials to a highlands-type regolith simulant can account for the increased reflectance of these volcanic regions. Reflectance variations across and within the sites can be explained by mixing of felsic mineral components, evolved-to-intermediate silicic compositions, andior silicic pyroclastic deposits.

• 出版日期2017-3-15