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Classification scheme for sedimentary and igneous rocks in Gale crater, Mars

Mangold, N. and Schmidt, M. E. and Fisk, M. R. and Forni, O. and McLennan, S. M. and Ming, D. W. and Sautter, V. and Sumner, D. and Williams, A. J. and Clegg, S. M. and Cousin, A. and Gasnault, O. and Gellert, R. and Grotzinger, J. P. and Wiens, R. C. (2017) Classification scheme for sedimentary and igneous rocks in Gale crater, Mars. Icarus, 284 . pp. 1-17. ISSN 0019-1035. doi:10.1016/j.icarus.2016.11.005.

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Rocks analyzed by the Curiosity rover in Gale crater include a variety of clastic sedimentary rocks and igneous float rocks transported by fluvial and impact processes. To facilitate the discussion of the range of lithologies, we present in this article a petrological classification framework adapting terrestrial classification schemes to Mars compositions (such as Fe abundances typically higher than for comparable lithologies on Earth), to specific Curiosity observations (such as common alkali-rich rocks), and to the capabilities of the rover instruments. Mineralogy was acquired only locally for a few drilled rocks, and so it does not suffice as a systematic classification tool, in contrast to classical terrestrial rock classification. The core of this classification involves (1) the characterization of rock texture as sedimentary, igneous or undefined according to grain/crystal sizes and shapes using imaging from the ChemCam Remote Micro-Imager (RMI), Mars Hand Lens Imager (MAHLI) and Mastcam instruments, and (2) the assignment of geochemical modifiers based on the abundances of Fe, Si, alkali, and S determined by the Alpha Particle X-ray Spectrometer (APXS) and ChemCam instruments. The aims are to help understand Gale crater geology by highlighting the various categories of rocks analyzed by the rover. Several implications are proposed from the cross-comparisons of rocks of various texture and composition, for instance between in place outcrops and float rocks. All outcrops analyzed by the rover are sedimentary; no igneous outcrops have been observed. However, some igneous rocks are clasts in conglomerates, suggesting that part of them are derived from the crater rim. The compositions of in-place sedimentary rocks contrast significantly with the compositions of igneous float rocks. While some of the differences between sedimentary rocks and igneous floats may be related to physical sorting and diagenesis of the sediments, some of the sedimentary rocks (e.g., potassic rocks) cannot be paired with any igneous rocks analyzed so far. In contrast, many float rocks, which cannot be classified from their poorly defined texture, plot on chemistry diagrams close to float rocks defined as igneous from their textures, potentially constraining their nature.

Item Type:Article
Related URLs:
URLURL TypeDescription
Mangold, N.0000-0002-0022-0631
Forni, O.0000-0001-6772-9689
McLennan, S. M.0000-0003-4259-7178
Ming, D. W.0000-0003-0567-8876
Sautter, V.0000-0002-4263-7558
Williams, A. J.0000-0001-6299-0845
Clegg, S. M.0000-0002-0338-0948
Cousin, A.0000-0001-7823-7794
Gasnault, O.0000-0002-6979-9012
Gellert, R.0000-0001-7928-834X
Grotzinger, J. P.0000-0001-9324-1257
Wiens, R. C.0000-0002-3409-7344
Additional Information:© 2016 Elsevier Inc. Received 20 June 2016, Revised 3 November 2016, Accepted 4 November 2016, Available online 5 November 2016. Imaging and chemical data presented here are available in the NASA Planetary Data System (PDS) We are grateful to the MSL engineering and management teams (and especially the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA) for making the mission and this scientific investigation possible and to science team members who contributed to mission operations. The APXS instrument is managed and financed by the Canadian Space Agency (CSA). Development and operation of the ChemCam instrument was supported in France by funds from the French space agency, Centre National d'Etudes Spatiales (CNES) and in the US by NASA funding to the Mars Exploration Program.
Funding AgencyGrant Number
Canadian Space Agency (CSA)UNSPECIFIED
Centre National d'Etudes Spatiales (CNES)UNSPECIFIED
Record Number:CaltechAUTHORS:20170223-070215020
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Official Citation:N. Mangold, M.E. Schmidt, M.R. Fisk, O. Forni, S.M. McLennan, D.W. Ming, V. Sautter, D. Sumner, A.J. Williams, S.M. Clegg, A. Cousin, O. Gasnault, R. Gellert, J.P. Grotzinger, R.C. Wiens, Classification scheme for sedimentary and igneous rocks in Gale crater, Mars, Icarus, Volume 284, 1 March 2017, Pages 1-17, ISSN 0019-1035, (
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:74482
Deposited By: Tony Diaz
Deposited On:02 Mar 2017 02:35
Last Modified:11 Nov 2021 05:27

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