The Geology of Ceres: an Overview

Thursday, 17 December 2015: 11:20
2007 (Moscone West)
Ralf Jaumann1, Christopher T Russell2, Carol A Raymond3, Harry Y McSween Jr4, David A Williams5, Debra Buczkowski6, Harald Hiesinger7, Maria Cristina De Sanctis8, Andreas Nathues9, Frank Preusker10, Thomas Roatsch11, Eleonora Ammannito12, Katharina Otto13, Katrin Krohn11, Katrin Stephan14, Klaus-Dieter Matz14, Stefan Elgner10, Elke Kersten10, Roland J Wagner11, Stefan Schroeder15, Franziska Schulzeck11, Isabel von der Gathen11, Nico Schmedemann16, Thomas Kneissl16, Adrian Nessemann16, Jennifer E. C. Scully3, Scott C Mest17, Simone Marchi18, Paul Schenk19 and Thomas B McCord20, (1)DLR - German Aerospace Center, Institute of Planetary Research, Berlin, Germany, (2)University of California Los Angeles, IGPP/EPSS, Los Angeles, CA, United States, (3)NASA Jet Propulsion Laboratory, Pasadena, CA, United States, (4)University of Tennessee, Knoxville, TN, United States, (5)Arizona State University, Tempe, AZ, United States, (6)JHU Applied Physics Laboratory, Laurel, MD, United States, (7)University of Münster, Münster, Germany, (8)IAPS-INAF, Rome, Italy, (9)Max Planck Institute for Solar System Research, Katlenburg-Lindau, Germany, (10)German Aerospace Center (DLR), Berlin, Germany, (11)German Aerospace Center DLR Berlin, Berlin, Germany, (12)University of California Los Angeles, Los Angeles, CA, United States, (13)German Aerospace Centre (DLR), Berlin, Germany, (14)German Aerospace Center, Berlin, Germany, (15)German Aerospace Center DLR Berlin, Institute of Planetary Research, Berlin, Germany, (16)Free University of Berlin, Berlin, Germany, (17)Planetary Science Institute Tucson, Tucson, AZ, United States, (18)Southwest Research Institute Boulder, Boulder, CO, United States, (19)Lunar and Planetary Institute, Houston, TX, United States, (20)Bear Fight Institute, Winthrop, WA, United States
Ceres exhibits geological features indicating significant resurfacing due to impact cratering, tectonic stress, relaxation, mass displacement, upwelling, doming and possible cryo-volcanic and/or cryo-glacial processes. Ceres’ surface is characterized by a smooth and rugged topography ranging from about -7.5km to 7.5km relative to a best-fit ellipsoidal shape with 482x482x446km. Ceres’ topography has a much greater range in elevation relative to its ellipsoidal dimensions (3.2%) than the Moon and Mars (1% and 0.9%) or Earth (0.3%) but is lower compared to Vesta (15%). Its topography is comparable to the icy satellite Iapetus (3.6%) but significantly higher than that of other icy satellites (<1.8%). The topography of Ceres indicates a rigid crust manifesting a range of processes at large and small scales in the course of its geological evolution. Impact craters of all sizes, central peaks and rings, and a variety of ejecta blankets, as well as lineaments, apparent depression infills and distinctive bright spots characterize Ceres’ surface. Impact craters range from pristine to highly degraded, comparable to that of various icy satellites, the Moon and Vesta, indicating an intensive cratering history over the age of the solar system as indicated by surface units with different crater densities. Some craters show upwelling dome-like structures on the floor. Bright spots with higher albedo than the surrounding terrain occur at different locations correlated with impact structures and tectonic crustal stress. These spots indicate material differences and possible time-variable effects related to cryo-processes either volcanic and/or glacial. Trough-like features and polygonal impact crater rims indicate crustal stress that compensates by tectonic processes. According to the relatively high topography to radius ratio, steep slopes, mass wasting, and flow processes are expected and observed. We thank the Dawn Science and Operations Team for their support.