Jarosite is a ferric hydrous sulfate mineral with the chemical formula of KFe3(SO4)2(OH)6 that has a trigonal crystal system and belongs to the group of alunite. This ocher-yellow or brown mineral forms under aqueous, acidic, and oxidizing conditions through, e.g., weathering of volcanic rocks in the presence of acidic, sulfur-rich fluids or by oxidation of sulfide minerals in acid drainage environments.
The Mössbauer spectrometer on Mars Exploration Rover Opportunity has detected up to 10 wt% of jarosite in the sedimentary rocks at Meridianum Planum (Klingelhöfer et al. 2004). This discovery was insofar a breakthrough, as it constrained the chemistry of the aqueous paleoenvironment with respect to its redox potential (being oxidizing) and its pH (being acidic). Furthermore, it is known that jarosite rapidly decomposes under humid conditions over geologic time, which suggests that the aqueous period of jarosite formation was followed by predominantly dry...
KeywordsVolcanic Rock Redox Potential Bioorganic Chemistry Sedimentary Rock Sulfide Mineral
- Klingelhöfer G, Morris RV, Bernhardt B, Schröder C, Rodionov DS, De Souza PA Jr, Yen A, Gellert R, Evlanov EN, Zubkov B, Foh J, Bonnes U, Kankeleit E, Gütlich P, Ming DW, Renz F, Wdowiak T, Squyres SW, Arvidson RE (2004) Jarosite and hematite at meridiani planum from opportunity’s Mössbauer spectrometer. Science 306:1740–1745CrossRefADSGoogle Scholar