Surficial Aqueous Geochemical Evolution

In a recent paper (Marion et al. 2003a), we quantified a conceptual model for the surficial aqueous geochemical evolution of Mars. This model rests 

Earth-like seawater 3MgC03 Mg(OH)2 3H20 + Na(Mg,Ca)CI,S04(HC03) 

This hypothetical early Mars water was subjected to concentration by evaporation we tracked its evolution until evaporation increased solutes by 

Solution Constituent A. Hypothetical early Mars watera B. 1000-fold concentration of Soln. A C. Soln. B at lowered Pco2 D. Terrestrial seawaterb E. Soln. C with 1.665 m H2SO4 F. Hypothetical Mars brinec 

1000-fold (Soln. B, Table 5.3). Because of the dominance of carbonate alkalinity in this solution, first siderite, then calcite, and finally hydromagnesite are predicted to precipitate at 0°C (Fig. 5.11). Because of the insolubility of siderite, very little of the original Fe2+ remains in solution after a 1000-fold concentration. This particular simulation assumed no 02(g). Fe2+ is unstable relative to Fe3+ minerals even at low levels of 02(g) (Fig. 5.12). The presence 

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