<b>FROM LAB TO ORBIT: SPECTRAL ANALYSES OF IGNEOUS ROCKS AND THEIR IMPLICATIONS FOR MARTIAN AND LUNAR SURFACES</b>

<p dir="ltr">Magmatic processes are a fundamental influence on the morphology and composition of terrestrial planets in our solar system. Investigating the makeup of igneous rocks produced by these processes gives us a powerful window into the thermal evolution of planetary bodies and the state of their interior through time. Through volcanic eruptions and the exposure of buried crustal material via impact or erosional processes on planetary surfaces, diverse igneous rocks are made available for study through orbital and landed space missions. In this dissertation, we use coordinated analyses of orbital and laboratory visible- to mid-infrared spectroscopy and complimentary petrologic data to significantly improve the interpretation and context of unique volcanic features on the Moon and feldspar-rich materials on Mars. With mineralogical maps generated from orbital and laboratory visible to near-infrared (VNIR) spectral data and lab VNIR spectra, we constrain competing formation hypotheses for irregular mare patches (IMPs), enigmatic volcanic features on the Moon that appear to have formed <100 My ago. We find that IMPs are glass-poor and unlikely to have formed by recent volcanic activity. More likely, they appear youthful because of an ongoing surface renewal process generated from a unique physical characteristic. We investigate the composition of the Gruithuisen domes, rare examples of silicic volcanism on the Moon, through orbital VNIR spectral analyses combined with laboratory thermal emission data of felsic/mafic mixtures and intermediate rocks measured in a simulated lunar environment. The results imply that the Gruithuisen domes are most consistent with an intermediate composition. Recently, there have been widespread VNIR detections of plagioclase feldspar on the surface of Mars with multiple competing hypotheses to explain these detections, as it is thought significant quantities of plagioclase are needed for detection. In a systematic laboratory study of a compositionally diverse suite of 41 felsic and feldspar-rich rocks, we characterize felsic and feldspar-rich whole rock VNIR spectra and explore the detection limits of plagioclase feldspar. We find that in coarse rocks, plagioclase is detectable at far lower abundances than previously thought, expanding the range of lithologies that may be responsible for Mars plagioclase detections. This dissertation significantly expands upon the limited existing studies of felsic rock compositions with direct application to observations on the Moon and Mars.</p>