- journal_title：American Mineralogist
- Contributor：Melissa D. Lane ; Janice L. Bishop ; M. Darby Dyar ; Penelope L. King ; Mario Parente ; Brendt C. Hyde
- Publisher：Mineralogical Society of America
- Date：2008-
- Format：text/html
- Language：en
- Identifier：10.2138/am.2008.2757
- journal_abbrev：American Mineralogist
- issn：0003-004X
- volume：93
- issue：5-6
- firstpage：728
- section：Articles
Visible, near-infrared, thermal, and Mössbauer spectroscopic data from the exposed, bright track soil at the “Paso Robles” site within Gusev crater, Mars, indicate the presence of Fe3+-sulfates and possibly Fe3+-phosphates admixed with the host soil. When the spectroscopic analyses are combined with constraints imposed by chemical data, the determined dominant Fe3+-sulfate component is hydrous, and all of the spectroscopic methods suggest that it is probably ferricopiapite or some closely related, structurally similar species, possibly mixed with other Fe3+ sulfates such as butlerite or parabutlerite, or perhaps (para)coquimbite, fibroferrite, or metahohmanite. Such an assemblage is consistent with formation in a highly oxidized, relatively dehydrated environment with the bulk-sulfate assemblage having OH/(OH + 2SO4) of < ~0.4. Some Fe3+ is likely to be associated with phosphates in the soil in the form of ferristrunzite or strengite.