¹Timmons M. Erickson, ¹Nicholas E. Timms, ¹Christopher L. Kirkland, ²Eric Tohver, ^1,3Aaron J. Cavosie, ⁴Mark A. Pearce, ¹Steven M. Reddy
Contributions to Mineralogy and Petrology 172, 11 Link to Article [doi:10.1007/s00410-017-1328-2]
¹TIGeR (The Institute of Geoscience Research), Department of Applied Geology, Curtin University, Perth, Australia
²School of Earth and Environment, University of Western Australia, Perth, Australia
³NASA Astrobiology Institute, Department of Geoscience, University of Wisconsin-Madison, Madison, USA
⁴CSIRO Mineral Resources, Australian Resources Research Centre, Kensington, Australia

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¹Nancy H. Thomas, ²Joshua L. Bandfield
Icarus (in Press) Link to Article [http://dx.doi.org/10.1016/j.icarus.2017.03.001]
¹Geological and Planetary Sciences, California Institute of Technology, Pasadena
²Space Science Institute
Copyright Elsevier

Factor analysis and target transformation techniques were applied to the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) spectral dataset to identify spectral endmembers, reduce noise, and automate image analysis. These techniques allow for rapid processing of images and identification of weak spectral signals. We have applied the automated technique to over 3000 CRISM images and successfully identified endmembers including phyllosilicates (e.g., serpentine, nontronite, and illite), sulfates (e.g., gypsum), carbonates (e.g., magnesite) and hydrated silica. To test these techniques, factor analysis and target transformation were applied to all available full spectral resolution covering the Nili Fossae region from 1.7 to 2. 6 µm data to identify the occurrence of Mg-carbonate in the region. We have also applied the factor analysis and target transformation as a noise reduction algorithm, which also allows for improved results from other common image analysis techniques, including spectral ratios and index maps.

¹Karl Cronberger, ¹Clive R. Neal
Meteoritics&Planetary Sciences(in Press) Link to Article [DOI: 10.1111/maps.12837]
¹Department of Civil & Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, IN, USA
Published by arrangement with John Wiley & Sons

Returned lunar KREEP basalts originated through impact processes or endogenous melting of the lunar interior. Various methods have been used to distinguish between these two origins, with varying degrees of success. Apollo 15 KREEP basalts are generally considered to be endogenous melts of the lunar interior. For example, sample 15434,181 is reported to have formed by a two-stage cooling process, with large orthopyroxene (Opx) phenocrysts forming first and eventually cocrystalizing with smaller plagioclase crystals. However, major and trace element analyses of Opx and plagioclase coupled with calculated equilibrium liquids are inconsistent with the large orthopyroxenes being a phenocryst phase. Equilibrium liquid rare earth element (REE) profiles are enriched relative to the whole rock (WR) composition, inconsistent with Opx being an early crystallizing phase, and these are distinct from the plagioclase REE equilibrium liquids. Fractional crystallization modeling using the Opx equilibrium liquids as a parental composition cannot reproduce the WR values even with crystallization of late-stage phosphates and zircon. This work concludes that instead of being a phenocryst phase, the large Opx crystals are actually xenocrysts that were subsequently affected by pyroxene overgrowths that formed intergrowths with cocrystallizing plagioclase.