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Constraints on iron sulfate and iron oxide mineralogy from ChemCam visible/near-infrared reflectance spectroscopy of Mt. Sharp basal units, Gale Crater, Mars

Johnson, Jeffrey R. and Bell, James F., III and Bender, Steve and Blaney, Diana and Cloutis, Edward and Ehlmann, Bethany and Fraeman, Abigail A. and Gasnault, Olivier and Kinch, Kjartan and Le Mouélic, Stéphane and Maurice, Sylvestre and Rampe, Elizabeth and Vaniman, David and Wiens, Roger C. (2016) Constraints on iron sulfate and iron oxide mineralogy from ChemCam visible/near-infrared reflectance spectroscopy of Mt. Sharp basal units, Gale Crater, Mars. American Mineralogist, 101 (7). pp. 1501-1514. ISSN 0003-004X. doi:10.2138/am-2016-5553.

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Relative reflectace point spectra (400–840 nm) were acquired by the Chemistry and Camera (ChemCam) instrument on the Mars Science Laboratory (MSL) rover Curiosity in passive mode (no laser) of drill tailings and broken rock fragments near the rover as it entered the lower reaches of Mt. Sharp and of landforms at distances of 2–8 km. Freshly disturbed surfaces are less subject to the spectral masking effects of dust, and revealed spectral features consistent with the presence of iron oxides and ferric sulfates. We present the first detection on Mars of a ~433 nm absorption band consistent with small abundances of ferric sulfates, corroborated by jarosite detections by the Chemistry and Mineralogy (CheMin) X-ray diffraction instrument in the Mojave, Telegraph Peak, and Confidence Hills drilled samples. Disturbed materials near the Bonanza King region also exhibited strong 433 nm bands and negative near-infrared spectral slopes consistent with jarosite. ChemCam passive spectra of the Confidence Hills and Mojave drill tailings showed features suggestive of the crystalline hematite identified by CheMin analyses. The Windjana drill sample tailings exhibited flat, low relative reflectance spectra, explained by the occurrence of magnetite detected by CheMin. Passive spectra of Bonanza King were similar, suggesting the presence of spectrally dark and neutral minerals such as magnetite. Long-distance spectra of the “Hematite Ridge” feature (3–5 km from the rover) exhibited features consistent with crystalline hematite. The Bagnold dune field north of the Hematite Ridge area exhibited low relative reflectance and near-infrared features indicative of basaltic materials (olivine, pyroxene). Light-toned layers south of Hematite Ridge lacked distinct spectral features in the 400–840 nm region, and may represent portions of nearby clay minerals and sulfates mapped with orbital near-infrared observations. The presence of ferric sulfates such as jarosite in the drill tailings suggests a relatively acidic environment, likely associated with flow of iron-bearing fluids, associated oxidation, and/or hydrothermal leaching of sedimentary rocks. Combined with other remote sensing data sets, mineralogical constraints from ChemCam passive spectra will continue to play an important role in interpreting the mineralogy and composition of materials encountered as Curiosity traverses further south within the basal layers of the Mt. Sharp complex.

Item Type:Article
Related URLs:
URLURL TypeDescription Materials
Johnson, Jeffrey R.0000-0002-5586-4901
Bell, James F., III0000-0002-2006-4074
Blaney, Diana0000-0002-4267-7939
Cloutis, Edward0000-0001-7301-0929
Ehlmann, Bethany0000-0002-2745-3240
Fraeman, Abigail A.0000-0003-4017-5158
Gasnault, Olivier0000-0002-6979-9012
Rampe, Elizabeth0000-0002-6999-0028
Vaniman, David0000-0001-7661-2626
Wiens, Roger C.0000-0002-3409-7344
Additional Information:© 2016 Mineralogical Society of America. Manuscript received September 6, 2015; Manuscript accepted January 22, 2016; First Published on July 01, 2016. Manuscript handled by Janice Bishop. This work was funded by the NASA Mars Science Laboratory Participating Scientist program through the Jet Propulsion Laboratory (contract 1350588). The U.S. portion of ChemCam and MSL rover operations was funded by NASA’s Mars Exploration Program. The French contribution to MSL is supported by the Centre National d’Etudes Spatiales (CNES). Work by K. Kinch was supported by the Danish Council for Independent Research/Natural Sciences (FNU grant 12-127126). A. Fraeman is supported by Keck Institute for Space Studies and Caltech GPS division Texaco postdoctoral fellowships. The authors thank W. Farrand and an anonymous reviewer for their helpful suggestions, and to J. Bishop for valuable editorial recommendations. Relative reflectance spectra used in Figures 10, 14, and 15 are available as supplemental material.
Group:Keck Institute for Space Studies
Funding AgencyGrant Number
Centre National d’Etudes Spatiales (CNES)UNSPECIFIED
Danish Council for Independent Research-Natural Sciences12-127126
Keck Institute for Space Studies (KISS)UNSPECIFIED
Subject Keywords:Mars spectroscopy, Mars remote sensing, visible/near-infrared, IR spectroscopy, ferric sulfates, iron oxides, Invited Centennial article
Issue or Number:7
Record Number:CaltechAUTHORS:20160708-102646735
Persistent URL:
Official Citation:Constraints on iron sulfate and iron oxide mineralogy from ChemCam visible/near-infrared reflectance spectroscopy of Mt. Sharp basal units, Gale Crater, Mars Jeffrey R. Johnson, James F. Bell, Steve Bender, Diana Blaney, Edward Cloutis, Bethany Ehlmann, Abigail Fraeman, Olivier Gasnault, Kjartan Kinch, Stéphane Le Mouélic, Sylvestre Maurice, Elizabeth Rampe, David Vaniman, Roger C. Wiens American Mineralogist Jul 2016, 101 (7) 1501-1514; DOI: 10.2138/am-2016-5553
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:68919
Deposited By: Tony Diaz
Deposited On:08 Jul 2016 23:46
Last Modified:11 Nov 2021 04:06

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