Microimaging Spectroscopy of Carbonaceous Chondrites and Comparison to the Spectral Diversity of Asteroids

Abstract Primitive asteroids and carbonaceous chondrites (CCs) record the history of processes in the early solar system. Visible and shortwave infrared (VSWIR) spectroscopy of primitive asteroids and bulk‐powdered CCs has identified shared spectral features suggestive of shared parent body origins. However, bulk powder CC spectra are spatially unresolved and destroy textures, which hinders tying shared spectral features to particular phases, petrologic contexts, and alteration histories. This study analyzes 20 CCs measured using microimaging hyperspectral VSWIR spectroscopy, recording over 700,000 individual spectra at the ∼80 μm/pixel scale. We compare CC spectral features with asteroids using the Expanded Bus‐DeMeo taxonomy. We introduce a spectral processing pipeline using Savitzky‐Golay filtering to better capture subtle spectral features, reduce noise and enhance comparisons between asteroid classes and CC subgroups and constituent phases. Key findings include a close spectral match between CM chondrites and Cgh‐class asteroids, as well as between CV3 chondrites and L‐class asteroids. Unaltered, iron‐bearing silicate CC components are similar to “stony” asteroid spectral classes. Furthermore, taxonomy‐based separation of CC spectra also identifies features unique to CCs, for example, oxidized iron signatures in CR2 chondrite NWA 7502 and other samples indicative of terrestrial weathering. Together these CC data show that primary and secondary Fe‐bearing minerals drive the separations in the asteroid classes expressed in the Expanded Bus‐DeMeo taxonomy. These findings also underscore the value of microimaging spectroscopy and statistically motivated frameworks in conducting larger surveys to interrogate the shared record of alteration in the early solar system. The data set is released for further study.