T110 The Geology of Dwarf Planet Ceres

Monday, 26 September 2016
8:00 AM - 12:00 PM
Room 201

THE GEOMORPHOLOGY OF CERES

Paper number: T110-3
Program: Technical Sessions
Time: 8:20 AM – 8:35 AM

Authors

Abstract

We assess the geology of Ceres at the global scale, to identify geomorphic and structural features, and to determine the geologic processes that have affected it globally. This three-dimensional characterization of the surface is used to determine if the geomorphology of Ceres is consistent with models of the dwarf planet predicting an icy crust and/or mantle.

Geomorphic features identified include: impact craters, linear structures, domical features and lobate flows. Ceres is dominated by craters, including numerous polygonal craters and craters with fractured floors. Kilometer-scale linear structures—grooves, pit crater chains, fractures and troughs—cross much of Ceres, and include both those associated with impact craters and those that do not appear to have any correlation to an impact event. Domical features fall into two broad classes: large domes which are 10s to 100s km in diameter with heights 1-5 km; and small mounds <10 km in diameter exhibiting sub-kilometer relief. A range of lobate flows are observed across the surface of Ceres, and differences in their morphology suggest that multiple emplacement processes might be operative.

A preliminary geologic map at a scale of 1:10M was constructed using Dawn Framing Camera images obtained during the Approach and Survey orbital phases. Surface features have been organized into discrete map units that are defined and characterized based on physical attributes. These units were then related to the putative geologic processes that produced them.

The lack of a large inventory of relaxed craters, the presence of ancient surface fractures, and extensive sub-surface fracturing (as demonstrated by the widespread distribution of polygonal craters), suggests that the crust is too strong to be dominated by ice. However, certain geomorphic features suggest that there may be at least some ice in the Ceres crust, and significant ice in its mantle. A latitudinal trend in the global distribution of lobate flows suggests that the differences in morphology might be explained by variations in ice content and temperature at the near-surface. Meanwhile, geomorphic and topographic analyses of both the floor fractured craters and the central dome in Occator suggest cryomagmatism has been active on Ceres. Also, Ahuna Mons and the other large domes appear to be cryovolcanic in nature.

Geological Society of America Abstracts with Programs. Vol. 48, No. 7

doi: 10.1130/abs/2016AM-282816

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