Item talk:Q258630

{

 "USGS Publications Warehouse": {
   "@context": "https://schema.org",
   "@type": "Article",
   "additionalType": "Journal Article",
   "name": "Identification of a basaltic component on the Martian surface from Thermal Emission Spectrometer data",
   "identifier": [
     {
       "@type": "PropertyValue",
       "propertyID": "USGS Publications Warehouse IndexID",
       "value": "70022687",
       "url": "https://pubs.usgs.gov/publication/70022687"
     },
     {
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       "propertyID": "USGS Publications Warehouse Internal ID",
       "value": 70022687
     },
     {
       "@type": "PropertyValue",
       "propertyID": "DOI",
       "value": "10.1029/1999JE001127",
       "url": "https://doi.org/10.1029/1999JE001127"
     }
   ],
   "journal": {
     "@type": "Periodical",
     "name": "Journal of Geophysical Research: Planets",
     "volumeNumber": "105",
     "issueNumber": "E4"
   },
   "inLanguage": "en",
   "isPartOf": [
     {
       "@type": "CreativeWorkSeries",
       "name": "Journal of Geophysical Research: Planets"
     }
   ],
   "datePublished": "2000",
   "dateModified": "2020-11-05",
   "abstract": "The Mars Global Surveyor Thermal Emission Spectrometer (TES) instrument collected 4.8\u00d7106\u00a0spectra of Mars during the initial aerobraking and science\u2010phasing periods of the mission (September 14, 1997, through April 29, 1998). Two previously developed atmosphere\u2010removal models were applied to data from Cimmeria Terra (25\u00b0S, 213\u00b0W). The surface spectra derived for these two models agree well, indicating that the surface and atmosphere emission can be separated and that the exact atmosphere\u2010removal model used has little effect on the derived surface composition. The Cimmeria spectra do not match terrestrial high\u2010silica igneous rocks (granite and rhyolite), ultramafic igneous rocks, limestone, or quartz\u2010 and clay\u2010rich sandstone and siltstone. A particulate (sand\u2010sized) sample of terrestrial flood basalt does provide an excellent match in both spectral shape and band depth to the Cimmeria spectrum over the entire TES spectral range. No unusual particle size effects are required to account for the observed spectral shape and depth. The implied grain size is consistent with the thermal inertia and albedo of this region, which indicate a sand\u2010sized surface with little dust. The identification of basalt is consistent with previous indications of pyroxene and basalt\u2010like compositions from visible/near\u2010infrared and thermal\u2010infrared spectral measurements. A linear spectral deconvolution model was applied to both surface\u2010only Cimmeria spectra using a library of 60 minerals to determine the composition and abundance of the component minerals. Plagioclase feldspar (45%; 53%) and clinopyroxene (26%; 19%) were positively identified above an estimated detection threshold of 10\u201315% for these minerals. The TES observations provide the first identification of feldspars on Mars. The best fit to the Mars data includes only clinopyroxene compositions; no orthopyroxene compositions are required to match the Cimmeria spectra. Olivine (12%; 12%) and sheet silicate (15%; 11%) were identified with lower confidence. Carbonates, quartz, and sulfates were not identified in Cimmeria at detection limits of \u223c5, 5, and 10%, respectively. Their presence elsewhere, however, remains open. The Cimmeria spectra are not well matched by any one SNC meteorite spectrum, indicating that this region is not characterized by a single SNC lithology. The occurrence of unweathered feldspar and pyroxene in Cimmeria, together with the inferred presence of pyroxene and unweathered basalts in other dark regions and at the Viking and Pathfinder landing sites, provides evidence that extensive global chemical weathering of materials currently exposed on the Martian surface has not occurred.",
   "description": "13 p.",
   "publisher": {
     "@type": "Organization",
     "name": "American Geophysical Union"
   },
   "author": [
     {
       "@type": "Person",
       "name": "Christensen, P. R.",
       "givenName": "P. R.",
       "familyName": "Christensen"
     },
     {
       "@type": "Person",
       "name": "Smith, M. D.",
       "givenName": "M. D.",
       "familyName": "Smith"
     },
     {
       "@type": "Person",
       "name": "Bandfield, J. L.",
       "givenName": "J. L.",
       "familyName": "Bandfield"
     },
     {
       "@type": "Person",
       "name": "Hamilton, V.E.",
       "givenName": "V.E.",
       "familyName": "Hamilton"
     },
     {
       "@type": "Person",
       "name": "Clark, Roger N. rclark@usgs.gov",
       "givenName": "Roger N.",
       "familyName": "Clark",
       "email": "rclark@usgs.gov",
       "identifier": {
         "@type": "PropertyValue",
         "propertyID": "ORCID",
         "value": "0000-0002-7021-1220",
         "url": "https://orcid.org/0000-0002-7021-1220"
       },
       "affiliation": [
         {
           "@type": "Organization",
           "name": "Crustal Geophysics and Geochemistry Science Center",
           "url": "https://www.usgs.gov/centers/geology-energy-and-minerals-science-center"
         }
       ]
     }
   ],
   "funder": [
     {
       "@type": "Organization",
       "name": "Crustal Geophysics and Geochemistry Science Center",
       "url": "https://www.usgs.gov/centers/geology-energy-and-minerals-science-center"
     }
   ],
   "spatialCoverage": [
     {
       "@type": "Place",
       "additionalType": "unknown",
       "name": "Mars",
       "url": "https://geonames.org/4709245"
     }
   ]
 }

}