INVESTIGATION OF ASTROBIOLOGICAL POTENTIAL OF LAVA TUBES IN NEW MEXICO

Lava tubes and basaltic caves are common features in volcanic terrains on Earth, and also Mars, where they have been identified based on orbital imagery and remote-sensing data. Caves are unique environments where both secondary mineral precipitation and microbial colonization and growth are enhanced by stable environmental conditions. Thus, they represent excellent locations where biosignatures can be formed and preserved within minerals. By analogy with terrestrial caves, caves on Mars may contain a record of secondary mineralization that would inform us on past aqueous activity. They may also represent the best locations to search for biosignatures.

The study of caves on Earth can be used to test hypotheses and better understand biogeochemical processes, and the signatures that these processes leave in mineral deposits. Caves may also serve as test beds for the development of exploration strategies and novel technologies for future missions to Mars. Here we present preliminary results on the geochemistry and mineralogy of secondary minerals and microbial rock coatings from contrasting (age, geographical setting) lava tubes in New Mexico. In particular, we present the results from portable field instruments used to perform non-destructive, in situ elemental (XRF) and mineralogical (Raman) analyses. These instruments represent a novel way of investigating cave deposits while minimizing the impact on the cave environment. The use of these instruments in such analog settings is also being conducted for the development of performance requirements for future space instruments.