Paper No. 54-2
Presentation Time: 1:50 PM
USING MINERALOGY OF THE BAGNOLD DUNE FIELD IN GALE CRATER TO INTERPRET EOLIAN SEDIMENT SORTING ON THE MARTIAN SURFACE
RAMPE, Elizabeth B.1, LAPOTRE, Mathieu G.A.2, BRISTOW, Thomas F.3, ARVIDSON, Raymond4, MORRIS, Richard V.5, ACHILLES, Cherie N.6, WEITZ, Catherine M.7, BLAKE, D.F.8, MING, Douglas W.1, MORRISON, Shaunna M.9, VANIMAN, David10, CHIPERA, Steve11, DOWNS, Robert T.12, EDGETT, K.S.13, GROTZINGER, John P.14, HAZEN, Robert M.9, PERETYAZHKO, Tanya15, SUTTER, Brad15, TU, Valerie M.15, YEN, Albert S.16, HORGAN, Briony17, CASTLE, Nicholas18, CRAIG, Patricia I.7, CZARNECKI, Sean M.19, DES MARAIS, David J.20, FARMER, Jack D.21, GABRIEL, Travis S.J.21, GELLERT, Ralf22, HARDGROVE, Craig J.19, MCADAM, Amy23, MOROOKIAN, John Michael M.16, SARRAZIN, Philippe24 and TREIMAN, A.H.25, (1)NASA Johnson Space Center, 2101 NASA Pkwy, Houston, TX 77058, (2)Pasadena, CA 91125, (3)NASA Ames Research Center, Moffett Field, CA 945035, (4)Earth and Planetary Sciences, Washington University IN St. Louis, 1 Brookings Drive, St. Louis, MO 63130, (5)NASA Johnson Space Center, Houston, TX 77058, (6)NASA Goddard Space Flight Center, Greenbelt, MD 20771, (7)Planetary Science Institute, 1700 East Fort Lowell, Suite 106, Tucson, AZ 85719, (8)Exobiology Branch, NASA Ames Research Center, Moffett Field, CA 945035, (9)Geophysical Laboratory, Carnegie Institution for Science, Washington, DC 20015, (10)NA, Planetary Science Institute, 1700 East Fort Lowell Road, Suite 106, Tucson, AZ 85719, (11)Chesapeake Energy, Oklahoma City, OK 73154, (12)Department of Geosciences, University of Arizona, Tucson, AZ 85721, (13)Malin Space Science Systems, P.O. Box 90148, San Diego, CA 92191-0148, (14)Geological and Planetary Sciences, California Institute of Technology, 1200 E. California Blvd, Pasadena, CA 91125, (15)Jacobs JETS Contract at NASA Johnson Space Center, Houston, TX 77058, (16)Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, (17)Earth, Atmospheric, and Planetary Sciences Department, Purdue University, 550 Stadium Mall Drive, West Lafayette, IN 47907; Earth, Atmospheric, and Planetary Sciences, Purdue University, West Lafayette, IN 47907, (18)Lunar and Planetary Institute, Houston, TX 77058, (19)School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287, (20)NASA, Ames Research Center, MS 239-4, Bldg. 239, Rm. 321, Moffett Field, CA 94035-0001, (21)School of Earth and Space Exploration, Arizona State University, PO Box 871404, Tempe, AZ 85287-1404, (22)Department of Physics, University of Guelph, Guelph, ON N1G 2W1, Canada, (23)NASA Goddard Space Flight Center, Code 699.0, Greenbelt, MD 20771, (24)SET Institute, Mountain View, CA 94043, (25)Lunar and Planetary Institute, 3600 Bay Area Blvd, Houston, TX 77058
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 CRISM and 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 <150 mm and delivered to the CheMin X-ray diffraction instrument for quantitative mineralogical analysis. CRISM-derived mineralogy of the Namib Dune and Mount Desert Island and CheMin-derived mineralogy of the Gobabeb and Ogunquit Beach samples can be used in a value-added manner to interpret grain segregation at the bedform to dune-field scale and evaluate contributions from local sediment sources. Models of CRISM data demonstrate that Mount Desert Island is more enriched in olivine and less enriched in plagioclase than Namib dune, suggesting that fine-grained mafic sediments are preferentially mobilized downwind. Curiosity data indicate olivine also forms a coarse lag on the lee sides of barchanoidal dunes. Minor abundances of hematite, quartz, and anhydrite and small differences in the crystal chemistry of plagioclase and pyroxene derived from CheMin data suggest that sediments from the underlying lacustrine rocks also contribute to the Bagnold sands.
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