Characterization of the acidic cold seep emplaced jarositic Golden Deposit, NWT, Canada, as an analogue for jarosite deposition on Mars

• Published in: Icarus
• Main Authors: Battler, Melissa M., Osinski, Gordon R., Lim, Darlene S. S., Davila, Alfonso F., Michel, Frederick A., Craig, Michael M., Izawa, Matthew R. M., Leoni, Lisa, Slater, Gregory F., Fairen, Alberto G., Preston, Louisa J., Banerjee, Neil R.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: 2012
• Subjects: Canada; Norman Wells; Northwest Territories; permafrost
• Online Access: https://oro.open.ac.uk/33744/; https://oro.open.ac.uk/33744/1/1-s2.0-S0019103512001893-main.pdf; https://doi.org/10.1016/j.icarus.2012.05.015

Surficial deposits of the OH-bearing iron sulfate mineral jarosite have been observed in several places on Mars, such as Meridiani Planum and Mawrth Vallis. The specific depositional conditions and mechanisms are not known, but by comparing martian sites to analogous locations on Earth, the conditions of formation and, thus, the martian depositional paleoenvironments may be postulated. Located in a cold semi-arid desert ~100 km east of Norman Wells, Northwest Territories, Canada, the Golden Deposit (GD) is visible from the air as a brilliant golden-yellow patch of unvegetated soil, approximately 140 m x 50 m. The GD is underlain by permafrost and consists of yellow sediment, which is precipitating from seeps of acidic, iron-bearing groundwater. On the surface, the GD appears as a patchwork of raised polygons, with acidic waters flowing from seeps in troughs between polygonal islands. Although UV-Vis-NIR spectral analysis detects only jarosite, mineralogy, as determined by X-Ray Diffraction and Inductively Coupled Plasma Emission Spectrometry, is predominantly natrojarosite and jarosite, with hydronium jarosite, goethite, quartz, clays, and small amounts of hematite. Water pH varies significantly over short distances depending on proximity to acid seeps, from 2.3 directly above seeps, to 5.7 several m downstream from seeps within the deposit, and up to 6.5 in ponds proximal to the deposit. Visual observations of microbial filament communities and phospholipid fatty acid analyses confirm that the GD is capable of supporting life for at least part of the year. Jarositic-bearing sediments extend beneath vegetation up to 70 m out from the deposit and are mixed with plant debris and minerals presumably weathered from bedrock and glacial till. This site is of particular interest because mineralogy (natrojarosite, jarosite, hematite, and goethite) and environmental conditions (permafrost and arid conditions) at the time of deposition are conceivably analogous to jarosite deposits on Mars. Most terrestrial analogues for ...