Distribution and formation of chlorides and phyllosilicates in Terra Sirenum, Mars

The Terra Sirenum region of Mars, located in the Noachian southern highlands, is mineralogically diverse, providing unique insight into ancient aqueous processes. Analyses of remote sensing data over the region indicate the presence of both Fe-or Mg-rich phyllosilicates and a spectrally unique deposit interpreted to be rich in chloride salts. The stratigraphic relationships indicate that the phyllosilicates are part of the ancient highland crust and that the salts were deposited at a later time. In some instances, there is clear morphological evidence that salts were mobilized and deposited by near-surface waters.