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Composition of conglomerates analyzed by the Curiosity rover: Implications for Gale Crater crust and sediment sources

Mangold, N. and Thompson, L. M. and Forni, O. and Williams, A. J. and Fabre, C. and Le Deit, L. and Wiens, R. C. and Williams, R. and Anderson, R. B. and Blaney, D. L. and Calef, F. and Cousin, A. and Clegg, S. M. and Dromart, G. and Dietrich, W. E. and Edgett, K. S. and Fisk, M. R. and Gasnault, O. and Gellert, R. and Grotzinger, J. P. and Kah, L. and Le Mouélic, S. and McLennan, S. M. and Maurice, S. and Meslin, P.-Y. and Newsom, H. E. and Palucis, M. C. and Rapin, W. and Sautter, V. and Siebach, K. L. and Stack, K. and Sumner, D. and Yingst, A. (2016) Composition of conglomerates analyzed by the Curiosity rover: Implications for Gale Crater crust and sediment sources. Journal of Geophysical Research. Planets, 121 (3). pp. 353-387. ISSN 2169-9097. doi:10.1002/2015je004977. https://resolver.caltech.edu/CaltechAUTHORS:20200902-130428741

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Abstract

The Curiosity rover has analyzed various detrital sedimentary rocks at Gale Crater, among which fluvial and lacustrine rocks are predominant. Conglomerates correspond both to the coarsest sediments analyzed and the least modified by chemical alteration, enabling us to link their chemistry to that of source rocks on the Gale Crater rims. In this study, we report the results of six conglomerate targets analyzed by Alpha‐Particle X‐ray Spectrometer and 40 analyzed by ChemCam. The bulk chemistry derived by both instruments suggests two distinct end‐members for the conglomerate compositions. The first group (Darwin type) is typical of conglomerates analyzed before sol 540; it has a felsic alkali‐rich composition, with a Na₂O/K₂O > 5. The second group (Kimberley type) is typical of conglomerates analyzed between sols 540 and 670 in the vicinity of the Kimberley waypoint; it has an alkali‐rich potassic composition with Na₂O/K₂O < 2. The variety of chemistry and igneous textures (when identifiable) of individual clasts suggest that each conglomerate type is a mixture of multiple source rocks. Conglomerate compositions are in agreement with most of the felsic alkali‐rich float rock compositions analyzed in the hummocky plains. The average composition of conglomerates can be taken as a proxy of the average igneous crust composition at Gale Crater. Differences between the composition of conglomerates and that of finer‐grained detrital sediments analyzed by the rover suggest modifications by diagenetic processes (especially for Mg enrichments in fine‐grained rocks), physical sorting, and mixing with finer‐grained material of different composition.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1002/2015je004977DOIArticle
http://pds-geosciences.wustl.edu/missions/mslRelated ItemNASA Planetary Data System (PDS)
ORCID:
AuthorORCID
Mangold, N.0000-0002-0022-0631
Blaney, D. L.0000-0002-4267-7939
Grotzinger, J. P.0000-0001-9324-1257
Siebach, K. L.0000-0002-6628-6297
Stack, K.0000-0003-3444-6695
Additional Information:© 2016 American Geophysical Union. Issue Online: 15 April 2016; Version of Record online: 16 March 2016; Accepted manuscript online: 04 March 2016; Manuscript accepted: 25 February 2016; Manuscript revised: 23 February 2016; Manuscript received: 05 November 2015. We are grateful to Marjorie Chan and two anonymous reviewers for their insightful comments. Development and operation of the ChemCam instrument was supported in France by funds from the French space agency, Centre National d'Etudes Spatiales (CNES). Support for development and operation in the U.S. was provided by NASA to the Mars Exploration Program and specifically to the MSL team. The APXS is managed and financed by the Canadian Space Agency (CSA). Imaging and chemical data presented here are available in the NASA Planetary Data System (PDS) http://pds‐geosciences.wustl.edu/missions/msl. 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.
Funders:
Funding AgencyGrant Number
Centre National d'Études Spatiales (CNES)UNSPECIFIED
NASA/JPL/CaltechUNSPECIFIED
Canadian Space Agency (CSA)UNSPECIFIED
Subject Keywords:Mars; fluvial; sedimentary rocks; Gale Crater
Issue or Number:3
DOI:10.1002/2015je004977
Record Number:CaltechAUTHORS:20200902-130428741
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20200902-130428741
Official Citation:Mangold, N., et al. (2016), Composition of conglomerates analyzed by the Curiosity rover: Implications for Gale Crater crust and sediment sources, J. Geophys. Res. Planets, 121, 353–387, doi:10.1002/2015JE004977
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:105219
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:08 Sep 2020 23:48
Last Modified:16 Nov 2021 18:41

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