Hydrothermal formation of Clay-Carbonate alteration assemblages in the Nili Fossae region of Mars

• Published in: Earth and planetary science letters Vol. 297; no. 1; pp. 174 - 182
• Main Authors: Brown, Adrian J., Hook, Simon J., Baldridge, Alice M., Crowley, James K., Bridges, Nathan T., Thomson, Bradley J., Marion, Giles M., de Souza Filho, Carlos R., Bishop, Janice L.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.08.2010
• Subjects: Alterations; carbonate; Carbonates; clay-carbonate alteration; CRISM; Earth; Geology; Mars; Minerals; Nili Fossae; Rock; Spectra; Australia, Western Australia; Australia, Western Australia, Warrawoona Group; Mars; Nili Fossae; CRISM; clay-carbonate alteration; carbonate
• ISSN: 0012-821X; 1385-013X
• DOI: 10.1016/j.epsl.2010.06.018

The Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) has returned observations of the Nili Fossae region indicating the presence of Mg-carbonate in small (< 10 km sq 2), relatively bright rock units that are commonly fractured (Ehlmann et al., 2008b). We have analyzed spectra from CRISM images and used co-located HiRISE images in order to further characterize these carbonate-bearing units. We applied absorption band mapping techniques to investigate a range of possible phyllosilicate and carbonate minerals that could be present in the Nili Fossae region. We also describe a clay-carbonate hydrothermal alteration mineral assemblage in the Archean Warrawoona Group of Western Australia that is a potential Earth analog to the Nili Fossae carbonate-bearing rock units. We discuss the geological and biological implications for hydrothermal processes on Noachian Mars.