The Martian mineralogical time scale

The Martian mineralogical time scale
The Martian mineralogical time scale Bibring et al (2006)'s new paradigm for Mars' geologic time scale included "three sequential eras characterized by their surface alteration products: (i) a nonacidic aqueous alteration, traced by phyllosilicates (the 'phyllosian' era); (ii) an acidic aqueous alteration, traced by sulfates (the 'theiikian' era); and (iii) an atmospheric aqueous-free alteration, traced by ferric oxides (the 'siderikian' era)." Jean-Pierre Bibring et al., 2006