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Silica deposits in the Nili Patera caldera on the Syrtis Major volcanic complex on Mars



The martian surface features abundant volcanoes and evidence for past liquid water. Extant or relict martian volcanic hydrothermal systems have therefore been sought in the pursuit of evidence for habitable environments1. The Mars Exploration Rover, Spirit, detected deposits highly enriched in silica with accessory minerals, suggesting formation by hydrothermal leaching of basaltic rocks by low-pH solutions2. However, extensive erosion has obscured the context of the formation environment of these deposits. Silica deposits have also been identified remotely, but also with limited contextual clues to their formation; aqueous alteration products of basalt and volcanic ash are the most likely sources3,4. Here we report the detection from orbit of hydrated silica deposits on the flanks of a volcanic cone in the martian Syrtis Major caldera complex. Near-infrared observations show dozens of localized hydrated silica deposits. As a result of the morphology of these deposits and their location in and around the cone summit, we suggest that the deposits were produced by a volcanically driven hydrothermal system. The cone and associated lava flows post-date Early Hesperian volcano formation. We conclude that, if a relict hydrothermal system was associated with the silica deposits, it may preserve one of the most recent habitable microenvironments on Mars.

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Figure 1: Image of the Nili Patera caldera in Syrtis Major.
Figure 2: CRISM and HiRISE observations of silica deposits.
Figure 3: Mineral deposit spectra indicative of Si–OH.


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This work is supported by the CRISM investigation on MRO under contract from JPL. Thanks to the MRO team for data collection, I. Spitale for HiRISE targeting, and S. Ruff, M. Rice, D. Morris and K. Seelos for discussion and analysis help.

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J.R.S. initiated the study, conducted the analysis and wrote manuscript. J.F.M. provided guidance, improved analysis and defined the focus of the work. B.L.E. contributed significantly to the analysis and manuscript contributions. R.E.M. provided research background and technique guidance. S.L.M. was responsible for data acquisition and manuscript refinement.

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Correspondence to J. R. Skok.

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Skok, J., Mustard, J., Ehlmann, B. et al. Silica deposits in the Nili Patera caldera on the Syrtis Major volcanic complex on Mars. Nature Geosci 3, 838–841 (2010).

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