Vestan lithologies mapped by the visual and infrared spectrometer on Dawn |
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| Authors: | Eleonora Ammannito M Cristina De Sanctis Fabrizio Capaccioni M Teresa Capria F Carraro Jean‐Philippe Combe Sergio Fonte Alessandro Frigeri Steven P Joy Andrea Longobardo Gianfranco Magni Simone Marchi Thomas B McCord Lucy A McFadden Harry Y McSween Ernesto Palomba Carle M Pieters Carol A Polanskey Carol A Raymond Jessica M Sunshine Federico Tosi Francesca Zambon Christopher T Russell |
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| Institution: | 1. Istituto di Astrofisica e Planetologia Spaziali, INAF, , Rome, Italy;2. Bear Fight Institute, , Winthrop, Washington, 98862 USA;3. Institute of Geophysics and Planetary Physics, University of California, , Los Angeles, California, 90095–1567 USA;4. NASA Lunar Science Institute, Southwest Research Institute, , Boulder, Colorado, 80302 USA;5. NASA Goddard Space Flight Center, , Greenbelt, Maryland, 20771 USA;6. Department of Earth and Planetary Sciences, University of Tennessee, , Knoxville, Tennessee, 37996–1410 USA;7. Department of Geological Sciences, Brown University, , Providence, Rhode Island, 02912 USA;8. Jet Propulsion Laboratory, , Pasadena, California, 91109 USA;9. University of Maryland, , College Park, Maryland, 20742–2421 USA |
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| Abstract: | We present global lithological maps of the Vestan surface based on Dawn mission's Visible InfraRed (VIR) Spectrometer acquisitions with a spatial sampling of 200 m. The maps confirm the results obtained with the data set acquired by VIR with a spatial sampling of 700 m, that the reflectance spectra of Vesta's surface are dominated by pyroxene absorptions that can be interpreted within the context of the distribution of howardites, eucrites, and diogenites (HEDs). The maps also partially agree with the ground and Hubble Space Telescope observations: they confirm the background surface being an assemblage of howardite or polymict eucrite, as well as the location of a diogenitic‐rich spot; however, there is no evidence of extended olivine‐rich regions in the equatorial latitudes. Diogenite is revealed on the Rheasilvia basin floor, indicating that material of the lower crust/mantle was exposed. VIR also detected diogenites along the scarp of Matronalia Rupes, and the rims of Severina and a nearby, unnamed crater, and as ejecta of Antonia crater. The diogenite distribution is fully consistent with petrological constraints; although the mapped distribution does not provide unambiguous constraints, it favors the hypothesis of a magma ocean. |
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