Using Chemcam Derived Geochemistry to Identify the Paleonet Sediment Transport Direction and Source Region Characteristics of the Stimson Formation in Gale Crater, Mars

Bedford, C C ; Schwenzer, S P ; Bridges, J C ; Banham, S ; Wiens, R C ; Frydenvang, J ; Gasnault, O ; Rampe, E B ; Gasda, P J

关键词: GEOCHEMISTRY;    SEDIMENT TRANSPORT;    MARS CRATERS;    FORMATIONS;    MARS SURFACE;    MARS (PLANET);    WIND (METEOROLOGY);    SANDSTONES;    DUNES;    DEPOSITS;    MARS ROVING VEHICLES;    SPECTRAL SIGNATURES;    LASER-INDUCED BREAKDOWN SPECTROSCOPY;    THICKNESS;   

RP-ID  :  LPI Contrib. No. 2132,JSC-E-DAA-TN66030

学科分类：空间科学

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来源: NASA Technical Reports Server

【 摘 要 】

The NASA Curiosity rover has encountered both ancient and modern dune deposits within Gale crater. The modern dunes are actively migrating across the surface within the Bagnold Dune field of which Curiosity conducted analysis campaigns at two different localities. Variations in mafic-felsic mineral abundances between these two sites have been related to the aeolian mineral sorting regime for basaltic environments identified on the Earth which become preferentially enriched in olivine relative to plagioclase feldspar with increasing distance from the source. This aeolian mineral sorting regime for basaltic minerals has also been inferred for Mars from orbital data. The aim of this study is to investigate whether this aeolian mafic-felsic mineral sorting trend has left a geochemical signature in the ancient dune deposits preserved within the Stimson formation. The Stimson formation unconformably overlies the Murray formation and consists of thickly laminated, cross-bedded sandstone. Stimson outcrops have a variable thickness up to 5 meters covering a total area of 17 square kilometers. A dry, aeolian origin was determined for this sandstone due to the high sphericity and roundness of the grains, uniform bimodal grain size distribution (250-710 microns), and 1-meter-thick cross-beds. Identifying the geochemical signature of mineral sorting can provide insights about the paleo-net sediment transport direction of the dunes and prevailing wind direction at the time of deposition.