P31H-06
Exploring Formation Models for Ceres Tholi and Montes

Wednesday, 16 December 2015: 09:15
2009 (Moscone West)
Ottaviano Ruesch1, Thomas Platz2, Lucy A McFadden3, Harald Hiesinger4, Paul Schenk5, Mark V Sykes6, Britney E Schmidt7, Debra Buczkowski8, Guneshwar Thangjam2, Carol A Raymond9 and Christopher T Russell10, (1)GSFC/Oak Ridge Associated Universities, Planetary Systems Laboratory, Greenbelt, MD, United States, (2)Max Planck Institute for Solar System Research, Katlenburg-Lindau, Germany, (3)NASA Goddard Space Flight Center, Greenbelt, MD, United States, (4)University of Münster, Münster, Germany, (5)Lunar and Planetary Institute, Houston, TX, United States, (6)Planetary Science Institute Tempe, Tempe, AZ, United States, (7)Georgia Institute of Technology Main Campus, Atlanta, GA, United States, (8)JHU Applied Physics Laboratory, Laurel, MD, United States, (9)NASA Jet Propulsion Laboratory, Pasadena, CA, United States, (10)University of California Los Angeles, IGPP/EPSS, Los Angeles, CA, United States
Abstract:
Dawn Framing Camera (FC) images of Ceres surface revealed tholi and mons, i.e., positive relief features with sub-circular to irregular basal shapes and varying height to diameter ratios and flank slopes. These domes and mounts are tentatively interpreted as volcanic constructs [1]. Alternative formation mechanisms, e.g., uplifting by diapirism or shallow intrusions [e.g., 2], could have also led to the observed features with different geological implications. FC images derived local digital elevation models reveal that the largest dome on Ceres (near Rongo crater) has a ~100 km wide base, concave downward margins with slopes of 10°-20°, a relatively flat top reaching altitudes of ~5 km relative to surrounding, and a summit pit chain of putative endogenic origin. A relevant mons on Ceres is a cone-shaped relief (10°S/316°E) with a ~30x20 km base, reaching a high of ~5 km relative to surroundings. Flank slopes approach a concave upward shape. These constructs are located in a complex geological area having resurfaced units with onlap contacts. Because of the varying morphometries of the reliefs, we explore several physical models of volcanic constructs, e.g., steep-sided dome and shield volcano. Physical models are based on radially spreading viscous gravity currents with a free upper surface [e.g., 3, 4]. Testing formation scenarios will exploit recently developed methods, such as time-variable viscosity and fixed-volume models [5], and constant flow rate models [6]. We aim to provide constraints on viable emplacement mechanisms for the different reliefs.

[1] Platz et al. (2015), EPSC abstract 915, vol. 10; [2] Fagents, S.A. (2003), JGR, vol. 108, E12, 5139; [3] Huppert, H. (1982), J. Fluid Mech., vol. 121, pp. 43-58; [4] Lacey et al. (1981), EPSL, vol. 54, pp. 139-143; [5] Glaze et al. (2012), LPSC abstract 1074 ; [6] Glaze et al. (2015), LPSC abstract 1326.

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