Aqueous alteration processes in Jezero crater, Mars—implications for organic geochemistry

The Perseverance rover landed in Jezero crater, Mars, in February 2021. We used the Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals (SHERLOC) instrument to perform deep-ultraviolet Raman and fluorescence spectroscopy of three rocks within the crater. We identify evidence for two distinct ancient aqueous environments at different times. Reactions with liquid water formed carbonates in an olivine-rich igneous rock. A sulfate-perchlorate mixture is present in the rocks, which probably formed by later modifications of the rocks by brine. Fluorescence signatures consistent with aromatic organic compounds occur throughout these rocks and are preserved in minerals related to both aqueous environments

Deciphering UV Spectroscopy on Earth and Mars

Spectroscopy consists of a variety of techniques that often probe materials with light. Light can be absorbed and excite particular chromophores that give insight into electronic structure or can be scattered that gives insight into vibrational structure. To enable successful measurements, one needs to understand the technology behind the spectroscopy and what parameters can be adjusted to affect signal to noise. The thesis presented here illustrates how absorption, fluorescence, and Raman spectroscopies can all be employed to determine the structure of molecules on Earth and how we can use analog datasets to predict what we observe on Mars