Abstract DGP2026-126

The abundance of SiO₂ on rocky planetary surfaces is a fundamental tracer of crustal composition and magmatic evolution. The position of the Christiansen Feature (CF) in the mid-infrared provides a mineralogically robust proxy for bulk silicate composition and, in particular, SiO₂ content. Here, we present the first independently calibrated global map of SiO₂ abundance for the lunar surface derived from CF data. The calibration is based on laboratory experiments with synthetic glasses spanning a wide compositional range (0.5 wt.% to 97.6 wt.% SiO₂), providing a direct and internally consistent link between CF position and SiO₂ abundance. Applying this experimentally achieved calibration to orbital thermal infrared measurements, we generate a quantitative global SiO₂ map of the Moon. The results clearly reproduce the mare–highland compositional dichotomy and are independently validated through comparison with samples returned from all major lunar landing sites, demonstrating the robustness of the approach. Importantly, we provide the first quantitative determination of SiO₂ abundances in the Moon’s high-silica regions. Elevated values of up to ~76 wt.% SiO₂ are derived for silicic volcanic complexes such as Gruithuisen, Hansteen Alpha, and the Lassell Massif. These results represent the first independently and experimentally calibrated quantification of high-SiO₂ terrains on the Moon and establish a new benchmark for assessing evolved magmatism on airless planetary bodies.