Spectral variability in naturally weathered rock surfaces and implications for Mars
Research Mentor(s)
Melissa Rice
Description
Rock weathering products are important clues for understanding past environmental conditions on Mars. They can be identified using reflectance spectroscopy because the formation of new minerals and textures on a rock surface will change its spectral signature. Previous studies demonstrate that the spectral signature of coated rock surfaces can vary with viewing geometry (the angle between incident and emitted light); however, these photometric effects have not been extensively characterized for naturally weathered rocks. Our goal is to quantify how both weathering and viewing geometry affect visible to near-infrared (VNIR) reflectance spectra of dunites, basalts, and andesites so that we can better interpret VNIR data from orbital and in-situ Mars missions. The Western Mars Lab’s hemispheric goniometer and spectrometer were used to collect reflectance spectroscopy data from natural rock surfaces at several geometries covering the full scattering hemisphere. Within this sample suite, weathered samples tend to have more backscattering behavior than relatively unaltered samples of the same rock type. Improving our understanding of how weathering changes the spectral signature of terrestrial samples can then be applied to Martian rocks to make inferences about their original compositions and environmental conditions that formed any weathering products present.
Document Type
Event
Start Date
May 2022
End Date
May 2022
Location
Carver Gym (Bellingham, Wash.)
Department
CBE - Geology
Genre/Form
student projects; posters
Type
Image
Rights
Copying of this document in whole or in part is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this document for commercial purposes, or for financial gain, shall not be allowed without the author’s written permission.
Language
English
Format
application/pdf
Spectral variability in naturally weathered rock surfaces and implications for Mars
Carver Gym (Bellingham, Wash.)
Rock weathering products are important clues for understanding past environmental conditions on Mars. They can be identified using reflectance spectroscopy because the formation of new minerals and textures on a rock surface will change its spectral signature. Previous studies demonstrate that the spectral signature of coated rock surfaces can vary with viewing geometry (the angle between incident and emitted light); however, these photometric effects have not been extensively characterized for naturally weathered rocks. Our goal is to quantify how both weathering and viewing geometry affect visible to near-infrared (VNIR) reflectance spectra of dunites, basalts, and andesites so that we can better interpret VNIR data from orbital and in-situ Mars missions. The Western Mars Lab’s hemispheric goniometer and spectrometer were used to collect reflectance spectroscopy data from natural rock surfaces at several geometries covering the full scattering hemisphere. Within this sample suite, weathered samples tend to have more backscattering behavior than relatively unaltered samples of the same rock type. Improving our understanding of how weathering changes the spectral signature of terrestrial samples can then be applied to Martian rocks to make inferences about their original compositions and environmental conditions that formed any weathering products present.