HOW TO MAKE A MARTIAN SEDIMENTARY ROCK: DIVERSITY IN TERRESTRIAL PROCESSES LEADING TO MARS ANALOG FEATURES

Terrestrial analogs provide the foundation for interpreting geologic data from Mars. Recent observations from orbiters and landers on Mars have revealed a wealth of information that suggest the significance of fluids in deposition and diagenesis of some of the lithified strata on Mars. Interpretation of the Martian processes that could have resulted in these deposits requires reverse modeling based on multiple terrestrial analogs. Field and analytical studies of modern and ancient terrestrial analog environments reveal how multiple geologic and depositional settings and geochemical pathways can result in sediments and outcrops with features that are analogous to the Mars strata. Sedimentary structures, diagenetic features, and unique minerals assemblages that are observed in the Martian strata are also present in modern interdune acid saline playa environments on the Archean Craton in Western Australia, modern active volcanic playas in the high Andes, Permian acid saline redbeds and evaporites in the mid-continent U.S., and groundwater altered zones of the Jurassic Navajo Sandstone. These various geologic settings result in similar mineralogical and sedimentological characteristics, presenting challenges for accurate environmental interpretations for Mars.