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Gypsum, bassanite, and anhydrite at Gale crater, Mars

Vaniman, David T. and Martínez, Germán M. and Rampe, Elizabeth B. and Bristow, Thomas F. and Blake, David F. and Yen, Albert S. and Ming, Douglas W. and Rapin, William and Meslin, Pierre-Yves and Morookian, John Michael and Downs, Robert T. and Chipera, Steve J. and Morris, Richard V. and Morrison, Shaunna M. and Treiman, Allan H. and Achilles, Cherie N. and Robertson, Kevin and Grotzinger, John P. and Hazen, Robert M. and Wiens, Roger C. and Sumner, Dawn Y. (2018) Gypsum, bassanite, and anhydrite at Gale crater, Mars. American Mineralogist, 103 (7). pp. 1011-1020. ISSN 0003-004X. doi:10.2138/am-2018-6346.

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Analyses by the CheMin X-ray diffraction instrument on Mars Science Laboratory show that gypsum, bassanite, and anhydrite are common minerals at Gale crater. Warm conditions (∼6 to 30 °C) within CheMin drive gypsum dehydration to bassanite; measured surface temperatures and modeled temperature depth profiles indicate that near-equatorial warm-season surface heating can also cause gypsum dehydration to bassanite. By accounting for instrumental dehydration effects we are able to quantify the in situ abundances of Ca-sulfate phases in sedimentary rocks and in eolian sands at Gale crater. All three Ca-sulfate minerals occur together in some sedimentary rocks and their abundances and associations vary stratigraphically. Several Ca-sulfate diagenetic events are indicated. Salinity-driven anhydrite precipitation at temperatures below ∼50 °C may be supported by co-occurrence of more soluble salts. An alternative pathway to anhydrite via dehydration might be possible, but if so would likely be limited to warmer near-equatorial dark eolian sands that presently contain only anhydrite. The polyphase Ca-sulfate associations at Gale crater reflect limited opportunities for equilibration, and they presage mixed salt associations anticipated in higher strata that are more sulfate-rich and may mark local or global environmental change. Mineral transformations within CheMin also provide a better understanding of changes that might occur in samples returned from Mars.

Item Type:Article
Related URLs:
URLURL TypeDescription
Vaniman, David T.0000-0001-7661-2626
Rampe, Elizabeth B.0000-0002-6999-0028
Bristow, Thomas F.0000-0001-6725-0555
Blake, David F.0000-0002-0834-4487
Ming, Douglas W.0000-0003-0567-8876
Rapin, William0000-0003-4660-8006
Meslin, Pierre-Yves0000-0002-0703-3951
Downs, Robert T.0000-0002-8380-7728
Treiman, Allan H.0000-0002-8073-2839
Achilles, Cherie N.0000-0001-9185-6768
Grotzinger, John P.0000-0001-9324-1257
Wiens, Roger C.0000-0002-3409-7344
Sumner, Dawn Y.0000-0002-7343-2061
Additional Information:© 2018 Mineralogical Society of America. Manuscript received October 24, 2017; Manuscript accepted March 21, 2018. This paper was improved with helpful reviews by Ron Peterson and Melissa Lane. Support from the NASA Mars Science Laboratory Mission for CheMin development and operation is gratefully acknowledged. Sulfate stability work by D.T.V. and S.J.C. was supported through Los Alamos National Laboratory Directed Research and Development funding, and NASA grant NNH10A083I.
Funding AgencyGrant Number
Los Alamos National LaboratoryUNSPECIFIED
Subject Keywords:Gypsum, bassanite anhydrite, X‑ray diffraction, Mars; Martian Rocks and Minerals: Perspectives from Rovers, Orbiters, and Meteorites
Issue or Number:7
Record Number:CaltechAUTHORS:20180702-095800652
Persistent URL:
Official Citation:David T. Vaniman, Germán M. Martínez, Elizabeth B. Rampe, Thomas F. Bristow, David F. Blake, Albert S. Yen, Douglas W. Ming, William Rapin, Pierre-Yves Meslin, John Michael Morookian, Robert T. Downs, Steve J. Chipera, Richard V. Morris, Shaunna M. Morrison, Allan H. Treiman, Cherie N. Achilles, Kevin Robertson, John P. Grotzinger, Robert M. Hazen, Roger C. Wiens, Dawn Y. Sumner; Gypsum, bassanite, and anhydrite at Gale crater, Mars. American Mineralogist ; 103 (7): 1011–1020. doi:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:87511
Deposited By: Tony Diaz
Deposited On:03 Jul 2018 18:13
Last Modified:15 Nov 2021 20:49

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