Mineralogy of explosive and effusive volcanic edifices in the Marius Hills Volcanic Complex

Abstract

The Marius Hills Volcanic Complex exhibits the highest concentration of extrusive volcanic landforms on the Moon, in the form of both domes and cones. The interpretive advancements made in this investigation result from improved spectral resolution and analysis techniques. Moon Mineralogy Mapper (M3) spectral analysis shows that the rounded landforms in MHVC exhibit spectra consistent with glass, confirming a cinder cone with an explosive volcanic origin. The presence of scoria-like glass-rich pyroclasts that should be distinct from the glass beads collected during Apollo. This research provides evidence that spectroscopy can identify volcanic landforms when visible images of the morphology are inconclusive, which is essential for future exploration of volcanic terrains. The likely concurrent eruption of the domes and cones with the differences in the mineralogy of the resulting edifices (e.g., presence of glass) add supporting evidence to the hypothesis that extrinsic properties (e.g., ascent rate), not changes in magma composition (e.g., amount of volatiles), led to the different volcanic morphologies. Combining the morphology and the spectral data, we hypothesize that the magma evolution of the region was long-lived and with distinct early edifice-forming and later mare-forming episodes. The long-lived volcanism recorded in multiple volcanic units within close proximity in MHVC would be ideal for future exploration and eventual sample return.