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Chemistry of fracture-filling raised ridges in Yellowknife Bay, Gale Crater: Window into past aqueous activity and habitability on Mars

Léveillé, Richard J. and Bridges, John and Wiens, Roger and Mangold, Nicolas and Cousin, Agnes and Lanza, Nina and Forni, Olivier and Ollila, Ann and Grotzinger, John and Clegg, Samuel and Siebach, Kirsten and Berger, Gilles and Clark, Benton C. and Fabre, Cécile and Anderson, Ryan and Gasnault, Olivier and Blaney, Diana and DeFlores, Lauren and Leshin, Laurie and Maurice, Sylvestre and Newsom, Horton E. (2014) Chemistry of fracture-filling raised ridges in Yellowknife Bay, Gale Crater: Window into past aqueous activity and habitability on Mars. Journal of Geophysical Research: Planets, 119 (11). pp. 2398-2415. ISSN 2169-9100.

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The ChemCam instrument package on the Curiosity rover was used to characterize distinctive raised ridges in the Sheepbed mudstone, Yellowknife Bay formation, Gale Crater. The multilayered, fracture-filling ridges are more resistant to erosion than the Sheepbed mudstone rock in which they occur. The bulk average composition of the raised ridges is enriched in MgO by 1.2–1.7 times (average of 8.3–11.4 wt %; single-shot maximum of 17.0 wt %) over that of the mudstone. Al_2O_3 is anticorrelated with MgO, while Li is somewhat enriched where MgO is highest. Some ridges show a variation in composition with different layers on a submillimeter scale. In particular, the McGrath target shows similar high-MgO resistant outer layers and a low-MgO, less resistant inner layer. This is consistent with the interpretation that the raised ridges are isopachous fracture-filling cements with a stratigraphy that likely reveals changes in fluid composition or depositional conditions over time. Overall, the average composition of the raised ridges is close to that of a Mg- and Fe-rich smectite, or saponite, which may also be the main clay mineral constituent of the host mudstone. These analyses provide evidence of diagenesis and aqueous activity in the early postdepositional history of the Yellowknife Bay formation, consistent with a low salinity to brackish fluid at near-neutral or slightly alkaline pH. The fluids that circulated through the fractures likely interacted with the Sheepbed mudstone and (or) other stratigraphically adjacent rock units of basaltic composition and leached Mg from them preferentially.

Item Type:Article
Related URLs:
URLURL TypeDescription
Bridges, John0000-0002-9579-5779
Wiens, Roger0000-0002-3409-7344
Mangold, Nicolas0000-0002-0022-0631
Cousin, Agnes0000-0001-7823-7794
Lanza, Nina0000-0003-4445-7996
Forni, Olivier0000-0001-6772-9689
Grotzinger, John0000-0001-9324-1257
Clegg, Samuel0000-0002-0338-0948
Siebach, Kirsten0000-0002-6628-6297
Clark, Benton C.0000-0002-5546-8757
Anderson, Ryan0000-0003-4465-2871
Gasnault, Olivier0000-0002-6979-9012
Blaney, Diana0000-0002-4267-7939
Newsom, Horton E.0000-0002-4358-8161
Additional Information:© 2014. American Geophysical Union. Received 31 JAN 2014. Accepted 16 JUL 2014. Accepted article online 18 JUL 2014. Published online 26 NOV 2014. Special Section: Results from the first 360 Solsof the Mars Science Laboratory Mission: Bradbury Landing through Yellowknife Bay The MSL mission is funded by NASA's Mars Program Office. R.J.L. received financial support from the Canadian Space Agency. The French contribution to ChemCam on MSL is supported by the Centre National d'Études Spatiales (CNES). We acknowledge the whole MSL team and JPL, in particular, for developing and leading this successful mission. We also thank the reviewers for their excellent comments, which greatly helped to improve the manuscript. The data reported in this paper are archived at the Planetary Data System, accessible at
Funding AgencyGrant Number
Canadian Space Agency (CSA)UNSPECIFIED
Centre National d'Études Spatiales (CNES)UNSPECIFIED
Subject Keywords:Mars; diagenesis; mudstone; smectite; magnesium; LIBS
Issue or Number:11
Record Number:CaltechAUTHORS:20170408-164219016
Persistent URL:
Official Citation:Léveillé, R. J., et al. (2014), Chemistry of fracture-filling raised ridges in Yellowknife Bay, Gale Crater: Window into past aqueous activity and habitability on Mars, J. Geophys. Res. Planets, 119, 2398–2415. doi:10.1002/2014JE004620.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:76235
Deposited By: 1Science Import
Deposited On:08 Mar 2018 23:42
Last Modified:09 Mar 2020 13:19

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