USING MINERALOGY OF THE BAGNOLD DUNE FIELD IN GALE CRATER TO INTERPRET EOLIAN SEDIMENT SORTING ON THE MARTIAN SURFACE

The Mars Science Laboratory Curiosity rover landed in Gale crater in August 2012 to characterize modern and ancient surface environments. Curiosity executed a two-phase campaign to study the morphology, activity, physical properties, and chemical and mineralogical composition of the Bagnold Dune Field, an active eolian dune field on the lower slopes of Aeolis Mons (Mount Sharp). Detectable aspects of dune sand mineralogy have been examined from orbit with the visible/short-wave infrared spectrometer CRISMand the thermal-infrared spectrometers THEMIS and TES. CRISM data demonstrate variations in plagioclase, pyroxene, and olivine abundances across the dune field. Curiosity analyzed sediments from two locations in the dune field to evaluate the causes of the mineralogical differences observed from orbit. The Gobabeb sample was collected from Namib Dune, a barchanoidal dune on the upwind margin of the dune field, and the Ogunquit Beach sample was collected from the Mount Desert Island sand patch located downwind from Namib. These samples were sieved to