Joseph Michalski

NASA Mars Data Analysis Program

Analysis of sulfate-bearing deposits at global, regional and local scales: Testing hypotheses of formation

In this work, we will rigorously text hypotheses of sulfate mineral formation on Mars using a combination of datasets to evaluate specific criteria relevant to each formation model. In addition to previous hypotheses for formation of sulfate-bearing terrains on Mars, we will also test a new one we have recently proposed. The new hypothesis is this: sulfate-bearing terrains at Meridiani Planum and possibly elsewhere, were created by proximal eolian re-working of a dusting sublimation residue that was chemically weathered within low-latitude ice deposits related to ancient polar wander or possibly obliquity excursions. We will test this model and the others by first spectroscopically mapping sulfate deposits at a global scale, then performing detailed studies of the each of the deposits to reveal their detailed mineralogy, the relationship of mineralogy to stratigraphy, lithology, erosional style, physical form of the deposits, surface textures, and regional geologic context. We will look for trends between deposits within the same region and we will attempt to make large scale regional or global-scale correlations and generalizations. We will also link the observations made from orbit to detailed understanding of the stratigraphy and composition of layered rocks explored by the Opportunity Rover. Together, this detailed picture built through data fusion and observation at multiple scales will favor one of the existing models of sulfate formation on Mars or point us to a new direction for interpreting these complex, enigmatic deposits.