The effects of magmatic evolution, crystallinity, and microtexture on the visible/near-infrared and thermal-infrared spectra of volcanic rocks

The natural chemical and physical variations that occur within volcanic rocks (petrology) provide critical insights into mantle crust conditions on terrestrial bodies. Visible/near-infrared (VNIR; 0.3–2.5 ?m) thermal infrared (TIR; 5–50 spectroscopy are the main tools available to remotely characterize these materials from satellites in orbit. However, accuracy of petrologic information can be gained spectra when exhibit complex mineralogy, crystallinity, microtexture occurring together settings is not well constrained. Here, we compare a suite planetary analog Three Sisters Volcanic Complex, Oregon their chemistry, X-ray diffraction, fluorescence, electron microprobe analysis. Our results indicate TIR an effective tool such for modeling bulk mineral chemistry. Given library with appropriate glass endmembers, derive abundance similar as other major groups first-order estimates wt.% SiO 2 glass-rich samples, but cannot effectively detect minor oxide minerals. In contrast, VNIR often yield non-unique mineralogic interpretations due overlapping absorption bands olivine, glass, Fe-bearing plagioclase. addition, find sub-micron oxides hosted transparent matrix material common fine-grained extrusive lower albedo suppress mafic bands, leading very different same mineralogy Mineralogical should treated rigorous indicators, supplement TIR-based petrology by providing unique constraints minerals, microtexture, alteration processes. • Thermal models glass-bearing rocks. Sub-micron minerals rock near-infrared absorptions. Overlapping absorptions near 1 ?m Near-infrared used alone petrology. Detailed remote possible through combined spectroscopy.