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The geological nature of dark material on Vesta and implications for the subsurface structure

Jaumann, R. and Nass, Andrea and Otto, K. and Krohn, Katrin and Stephan, K. and McCord, T.B. and Williams, D.A. and Raymond, C.A. and Blewett, D.T. and Hiesinger, H. and Yingst, R.A. and De Sanctis, M.C. and Palomba, E. and Roatsch, Thomas and Matz, K.-D. and Preusker, Frank and Scholten, Frank and Russell, C.T. (2014) The geological nature of dark material on Vesta and implications for the subsurface structure. Icarus, 240, 3 - 19. Elsevier. doi: 10.1016/j.icarus.2014.04.035. ISSN 0019-1035.

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Official URL: http://www.sciencedirect.com/science/article/pii/S0019103514002279


Abstract Deposits of dark material appear on Vesta’s surface as features of relatively low-albedo in the visible wavelength range of Dawn’s camera and spectrometer. Mixed with the regolith and partially excavated by younger impacts, the material is exposed as individual layered outcrops in crater walls or ejecta patches, having been uncovered and broken up by the impact. Dark fans on crater walls and dark deposits on crater floors are the result of gravity-driven mass wasting triggered by steep slopes and impact seismicity. The fact that dark material is mixed with impact ejecta indicates that it has been processed together with the ejected material. Some small craters display continuous dark ejecta similar to lunar dark-halo impact craters, indicating that the impact excavated the material from beneath a higher-albedo surface. The asymmetric distribution of dark material in impact craters and ejecta suggests non-continuous distribution in the local subsurface. Some positive-relief dark edifices appear to be impact-sculpted hills with dark material distributed over the hill slopes. Dark features inside and outside of craters are in some places arranged as linear outcrops along scarps or as dark streaks perpendicular to the local topography. The spectral characteristics of the dark material resemble that of Vesta’s regolith. Dark material is distributed unevenly across Vesta’s surface with clusters of all types of dark material exposures. On a local scale, some craters expose or are associated with dark material, while others in the immediate vicinity do not show evidence for dark material. While the variety of surface exposures of dark material and their different geological correlations with surface features, as well as their uneven distribution, indicate a globally inhomogeneous distribution in the subsurface, the dark material seems to be correlated with the rim and ejecta of the older Veneneia south polar basin structure. The origin of the dark material is still being debated, however, the geological analysis suggests that it is exogenic, from carbon-rich low-velocity impactors, rather than endogenic, from freshly exposed mafic material or melt, exposed or created by impacts.

Item URL in elib:https://elib.dlr.de/93875/
Document Type:Article
Additional Information:Bright and Dark Materials on Vesta
Title:The geological nature of dark material on Vesta and implications for the subsurface structure
AuthorsInstitution or Email of AuthorsAuthor's ORCID iD
Jaumann, R.ralf.jaumann (at) dlr.deUNSPECIFIED
Nass, AndreaUniverstität Potsdam, Institut für Geographie; andrea.nass (at) dlr.deUNSPECIFIED
Otto, K.katharina.otto (at) dlr.deUNSPECIFIED
Krohn, Katrinkatrin.krohn (at) dlr.dehttps://orcid.org/0000-0001-8518-4985
Stephan, K.katrin.stephan (at) dlr.deUNSPECIFIED
McCord, T.B.Bear Fight Center, Space Science InstituteUNSPECIFIED
Williams, D.A.Arizona State UniversityUNSPECIFIED
Raymond, C.A.Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109-8099, USAUNSPECIFIED
Blewett, D.T.Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USAUNSPECIFIED
Hiesinger, H.Westfälische Wilhelms-Universität MünsterUNSPECIFIED
Yingst, R.A.Planetary Science Institute, 1700 E. Ft. Lowell, Suite 106, Tucson, AZ, 85719, USAUNSPECIFIED
De Sanctis, M.C.Istituto Nazionale di Astrofisica, Rome, Italy.UNSPECIFIED
Palomba, E.Institute for Interplanetary Space Physics - INAF, Rome, ItalyUNSPECIFIED
Roatsch, Thomasthomas.roatsch (at) dlr.deUNSPECIFIED
Preusker, Frankfrank.preusker (at) dlr.deUNSPECIFIED
Russell, C.T.Institute of Geophysics, University of California, Los Angeles, Los Angeles, CA 90095UNSPECIFIED
Journal or Publication Title:Icarus
Refereed publication:Yes
Open Access:Yes
Gold Open Access:No
In ISI Web of Science:Yes
DOI :10.1016/j.icarus.2014.04.035
Page Range:3 - 19
Keywords:Asteroid Vesta; Geological processes; Cratering
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Space
HGF - Program Themes:Space Exploration
DLR - Research area:Raumfahrt
DLR - Program:R EW - Space Exploration
DLR - Research theme (Project):R - Project DAWN
Location: Berlin-Adlershof
Institutes and Institutions:Institute of Planetary Research > Planetary Geology
Deposited By: Krohn, Dr.rer.nat Katrin
Deposited On:18 Dec 2014 13:22
Last Modified:06 Sep 2019 15:26

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