The potassic sedimentary rocks in Gale Crater, Mars, as seen by ChemCam Onboard <i>Curiosity</i>

Laetitia Le Deit; Nicolas Mangold; Olivier Forni; Agnès Cousin; Jeremie Lasue; Susanne Schröder; Roger C. Wiens; Dawn Y. Sumner; Cecile Fabre; Katherine M. Stack; Ryan Anderson; Diana L. Blaney; Samuel M. Clegg; Gilles Dromart; Martin Fisk; Olivier Gasnault; John P. Grotzinger; Sanjeev Gupta; Nina Lanza; Stephane Le Mouélic; Sylvestre Maurice; Scott M. McLennan; Pierre-Yves Meslin; Marion Nachon; Horton E. Newsom; Valerie Payre; William Rapin; Melissa Rice; Violaine Sautter; Allan H. Treiman

doi:10.1002/2015JE004987

The potassic sedimentary rocks in Gale Crater, Mars, as seen by ChemCam Onboard Curiosity

Journal of Geophysical Research

By: Laetitia Le Deit, Nicolas Mangold, Olivier Forni, Agnès Cousin, Jeremie Lasue, Susanne Schröder, Roger C. Wiens, Dawn Y. Sumner, Cecile Fabre, Katherine M. Stack, Ryan Anderson, Diana L. Blaney, Samuel M. Clegg, Gilles Dromart, Martin Fisk, Olivier Gasnault, John P. Grotzinger, Sanjeev Gupta, Nina Lanza, Stephane Le Mouélic, Sylvestre Maurice, Scott M. McLennan, Pierre-Yves Meslin, Marion Nachon, Horton E. Newsom, Valerie Payre, William Rapin, Melissa Rice, Violaine Sautter, and Allan H. Treiman

https://doi.org/10.1002/2015JE004987

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Abstract

The Mars Science Laboratory rover Curiosity encountered potassium-rich clastic sedimentary rocks at two sites in Gale Crater, the waypoints Cooperstown and Kimberley. These rocks include several distinct meters thick sedimentary outcrops ranging from fine sandstone to conglomerate, interpreted to record an ancient fluvial or fluvio-deltaic depositional system. From ChemCam Laser-Induced Breakdown Spectroscopy (LIBS) chemical analyses, this suite of sedimentary rocks has an overall mean K₂O abundance that is more than 5 times higher than that of the average Martian crust. The combined analysis of ChemCam data with stratigraphic and geographic locations reveals that the mean K₂O abundance increases upward through the stratigraphic section. Chemical analyses across each unit can be represented as mixtures of several distinct chemical components, i.e., mineral phases, including K-bearing minerals, mafic silicates, Fe-oxides, and Fe-hydroxide/oxyhydroxides. Possible K-bearing minerals include alkali feldspar (including anorthoclase and sanidine) and K-bearing phyllosilicate such as illite. Mixtures of different source rocks, including a potassium-rich rock located on the rim and walls of Gale Crater, are the likely origin of observed chemical variations within each unit. Physical sorting may have also played a role in the enrichment in K in the Kimberley formation. The occurrence of these potassic sedimentary rocks provides additional evidence for the chemical diversity of the crust exposed at Gale Crater.

Additional publication details
Publication type	Article
Publication Subtype	Journal Article
Title	The potassic sedimentary rocks in Gale Crater, Mars, as seen by ChemCam Onboard Curiosity
Series title	Journal of Geophysical Research
DOI	10.1002/2015JE004987
Volume	121
Issue	5
Year Published	2016
Language	English
Publisher	American Geophysical Union
Publisher location	Washington, D.C.
Contributing office(s)	Astrogeology Science Center
Description	21 p.
First page	784
Last page	804
Other Geospatial	Gale, crater on Mars near the northwestern part of the Aeolis quadrangle at 5.4°S 137.8°E; 154 km (96 mi) in diameter and about 3.5-3.8 billion years old
Online Only (Y/N)	N
Additional Online Files (Y/N)	N
Google Analytic Metrics	Metrics page