1. Oxidation Of Manganese At Kimberley, Gale Crater: More Free Oxygen In Mars' Past?
- Author
-
Lanza, N. L, Wiens, R. C, Arvidson, R. E, Clark, B. C, Fischer, W. W, Gellert, R, Grotzinger, J. P, Hurowitz, J. A, McLennan, S. M, Morris, R. V, Rice, M. S, Bell, J. F., III, Berger, J. A, Blaney, D. L, Bridges, N. T, Calef, F., III, Campbell, J. L, Clegg, S. M, Cousin, A, Edgett, K. S, Fabre, C, Fisk, M. R, Forni, O, Frydenvang, J, and Ming, D. W
- Subjects
Chemistry And Materials (General) ,Lunar And Planetary Science And Exploration - Abstract
High Mn concentrations provide unique indicators of water-rich environments and their redox state. Very high-potential oxidants are required to oxidize Mn to insoluble, high-valence oxides that can precipitate and concentrate Mn in rocks and sediments; these redox potentials are much higher than those needed to oxidize Fe or S. Consequently, Mn-rich rocks on Earth closely track the rise of atmospheric oxygen. Given the association between Mn-rich rocks and the redox state of surface environments, observations of anomalous Mn enrichments on Mars raise similar questions about redox history, solubility and aqueous transport, and availability as a metabolic substrate. Our observations suggest that at least some of the high Mn present in Gale crater occurs in the form of Mn-oxides filling veins that crosscut sand-stones, requiring post-depositional precipitation as highly oxidizing fluids moved through the fractured strata after their deposition and lithification.
- Published
- 2015