Elemental Geochemistry of Sedimentary Rocks at Yellowknife Bay, Gale Crater, Mars

Sedimentary rocks examined by the Curiosity rover at Yellowknife Bay, Mars, were derived from sources that evolved from an approximately average martian crustal composition to one influenced by alkaline basalts. No evidence of chemical weathering is preserved, indicating arid, possibly cold, paleocl...

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Bibliographic Details
Published in:Science
Main Authors: McLennan, S. M., Anderson, R. B., Bell, J. F., Bridges, J. C., Calef, F., Campbell, J. L., Clark, B. C., Clegg, S., Conrad, P., Cousin, A., Des Marais, D. J., Dromart, G., Dyar, M. D., Edgar, L. A., Ehlmann, B. L., Fabre, C., Forni, O., Gasnault, O., Gellert, R., Gordon, S., Grant, J. A., Grotzinger, J. P., Gupta, S., Herkenhoff, K. E., Hurowitz, J. A., King, P. L., Le Mouélic, S., Leshin, L. A., Léveillé, R., Lewis, K. W., Mangold, N., Maurice, S., Ming, D. W., Morris, R. V., Nachon, M., Newsom, H. E., Ollila, A. M., Perrett, G. M., Rice, M. S., Schmidt, M. E., Schwenzer, S. P., Stack, K., Stolper, E. M., Sumner, D. Y., Treiman, A. H., VanBommel, S., Vaniman, D. T., Vasavada, A., Wiens, R. C., Yingst, R. A.
Format: Article in Journal/Newspaper
Language:English
Published: American Association for the Advancement of Science (AAAS) 2014
Subjects:
Yellowknife
Online Access:http://dx.doi.org/10.1126/science.1244734
https://www.science.org/doi/pdf/10.1126/science.1244734
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Summary:Sedimentary rocks examined by the Curiosity rover at Yellowknife Bay, Mars, were derived from sources that evolved from an approximately average martian crustal composition to one influenced by alkaline basalts. No evidence of chemical weathering is preserved, indicating arid, possibly cold, paleoclimates and rapid erosion and deposition. The absence of predicted geochemical variations indicates that magnetite and phyllosilicates formed by diagenesis under low-temperature, circumneutral pH, rock-dominated aqueous conditions. Analyses of diagenetic features (including concretions, raised ridges, and fractures) at high spatial resolution indicate that they are composed of iron- and halogen-rich components, magnesium-iron-chlorine–rich components, and hydrated calcium sulfates, respectively. Composition of a cross-cutting dike-like feature is consistent with sedimentary intrusion. The geochemistry of these sedimentary rocks provides further evidence for diverse depositional and diagenetic sedimentary environments during the early history of Mars.

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