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Geologic Mapping of VestaWe report on a preliminary global geologic map of Vesta, based on data from the Dawn spacecraft's High- Altitude Mapping Orbit (HAMO) and informed by Low-Altitude Mapping Orbit (LAMO) data. This map is part of an iterative mapping effort; the geologic map has been refined with each improvement in resolution. Vesta has a heavily-cratered surface, with large craters evident in numerous locations. The south pole is dominated by an impact structure identified before Dawn's arrival. Two large impact structures have been resolved: the younger, larger Rheasilvia structure, and the older, more degraded Veneneia structure. The surface is also characterized by a system of deep, globe-girdling equatorial troughs and ridges, as well as an older system of troughs and ridges to the north. Troughs and ridges are also evident cutting across, and spiraling arcuately from, the Rheasilvia central mound. However, no volcanic features have been unequivocally identified. Vesta can be divided very broadly into three terrains: heavily-cratered terrain; ridge-and-trough terrain (equatorial and northern); and terrain associated with the Rheasilvia crater. Localized features include bright and dark material and ejecta (some defined specifically by color); lobate deposits; and mass-wasting materials. No obvious volcanic features are evident. Stratigraphy of Vesta's geologic units suggests a history in which formation of a primary crust was followed by the formation of impact craters, including Veneneia and the associated Saturnalia Fossae unit. Formation of Rheasilvia followed, along with associated structural deformation that shaped the Divalia Fossae ridge-and-trough unit at the equator. Subsequent impacts and mass wasting events subdued impact craters, rims and portions of ridge-and-trough sets, and formed slumps and landslides, especially within crater floors and along crater rims and scarps. Subsequent to the formation of Rheasilvia, discontinuous low-albedo deposits formed or were emplaced; these lie stratigraphically above the equatorial ridges that likely were formed by Rheasilvia. The last features to be formed were craters with bright rays and other surface mantling deposits. Executed progressively throughout data acquisition, the iterative mapping process provided the team with geologic proto-units in a timely manner. However, interpretation of the resulting map was hampered by the necessity to provide the team with a standard nomenclature and symbology early in the process. With regard to mapping and interpreting units, the mapping process was hindered by the lack of calibrated mineralogic information. Topography and shadow played an important role in discriminating features and terrains, especially in the early stages of data acquisition.
Document ID
20150001341
Acquisition Source
Goddard Space Flight Center
Document Type
Reprint (Version printed in journal)
Authors
Yingst, R. A.
(Planetary Science Inst. Tucson, AZ, United States)
Mest, S. C.
(Planetary Science Inst. Tucson, AZ, United States)
Berman, D. C.
(Planetary Science Inst. Tucson, AZ, United States)
Garry, W. B.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Williams, D. A.
(Arizona State Univ. Tempe, AZ, United States)
Buczkowski, D.
(Johns Hopkins Univ. Laurel, MD, United States)
Jaumann, R.
(Deutsches Zentrum fuer Luft- und Raumfahrt e.V. Berlin, Germany)
Pieters, C. M.
(Brown Univ. Providence, RI, United States)
De Sanctis, M. C.
(National Institute of Astrophysics Rome, Italy)
Frigeri, A.
(National Institute of Astrophysics Rome, Italy)
Le Corre, L.
(Max-Planck Inst. for Solar System Research Germany)
Preusker, F.
(Deutsches Zentrum fuer Luft- und Raumfahrt e.V. Berlin, Germany)
Raymond, C. A.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Reddy, V.
(Max-Planck Inst. for Solar System Research Germany)
Russell, C. T.
(California Univ. Los Angeles, CA, United States)
Roatsch, T.
(Deutsches Zentrum fuer Luft- und Raumfahrt e.V. Berlin, Germany)
Schenk, P. M.
(Lunar and Planetary Inst. Houston, TX, United States)
Date Acquired
February 5, 2015
Publication Date
January 3, 2014
Publication Information
Publication: Planetary and Space Science
Publisher: Elsevier
Volume: 103
Subject Category
Lunar And Planetary Science And Exploration
Report/Patent Number
GSFC-E-DAA-TN19235
Funding Number(s)
CONTRACT_GRANT: NNX10AR19G
CONTRACT_GRANT: 1/004/12/0
Distribution Limits
Public
Copyright
Public Use Permitted.
Keywords
Vesta
Geologic Mapping
Dawn
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