High manganese concentrations in rocks at Gale crater, Mars

Nina L. Lanza (1) , Woodward W. Fischer (2) , Roger C. Wiens (1) , John Grotzinger (2) , Ann M. Ollila (3, 4) , Agnes Cousin (1) , Ryan B. Anderson (5) , Benton C. Clark (6) , Ralf Gellert (7) , Nicolas Mangold (8) , Sylvestre Maurice (9) , Stéphane Le Mouélic (8) , Marion Nachon (8) , Mariek Schmidt (10) , Jeffrey Berger (11) , Samuel M. Clegg (1) , Olivier Forni (9) , Craig Hardgrove (12) , Noureddine Melikechi (13) , Horton E. Newsom (3) , Violaine Sautter (14)

1 LANL - Los Alamos National Laboratory
2 Division of Geological and Planetary Sciences [Pasadena]
3 IOM - Institute of Meteoritics [Albuquerque]
4 Now at Chevron Energy Technology Company
5 US Geological Survey [Flagstaff]
6 SSI - Space Science Institute [Boulder]
7 Department of Physics [Guelph]
8 LPG - Laboratoire de Planétologie et Géodynamique [UMR 6112]
9 IRAP - Institut de recherche en astrophysique et planétologie
10 Department of Earth Sciences [St. Catharines]
11 Department of Earth Sciences [London, ON]
12 SESE - ASU School of Earth and Space Exploration
13 Department of Physics and Engineering
14 MNHN - Muséum national d'Histoire naturelle

The surface of Mars has long been considered a relatively oxidizing environment, an idea supported by the abundance of ferric iron phases observed there. However, compared to iron, manganese is sensitive only to high redox potential oxidants, and when concentrated in rocks, it provides a more specific redox indicator of aqueous environments. Observations from the ChemCam instrument on the Curiosity rover indicate abundances of manganese in and on some rock targets that are 1–2 orders of magnitude higher than previously observed on Mars, suggesting the presence of an as-yet unidentified manganese-rich phase. These results show that the Martian surface has at some point in time hosted much more highly oxidizing conditions than has previously been recognized

Domaines: Planète et Univers [physics]

Nina L. Lanza, Woodward W. Fischer, Roger C. Wiens, John Grotzinger, Ann M. Ollila, et al.. High manganese concentrations in rocks at Gale crater, Mars. Geophysical Research Letters, 2014, 41 (16), pp.5755-5763. ⟨10.1002/2014GL060329⟩. ⟨hal-01131356⟩