TESTING SUBSURFACE MASS MIGRATION PROCESSES ON CERES (Invited Presentation)

The dwarf planet Ceres, located in the asteroid belt, defied pre-Dawn mission predictions by presenting a more complicated geologic history than expected, throwing many hypotheses on its origin and formation back for reconsideration. An intriguing clue into Ceres’ subsurface may be found in the observation of large domal features found globally, but not uniformly across Ceres [1]. These uplift features may represent solid-state mass migration such as salt doming [1] or cryomagmatic activity [1,2], both of which inform Ceres’ internal state.

We seek to understand the underlying mass migration creating the domal features in order to provide constraints on several competing hypotheses. In general, these domal uplift regions show morphometric signatures similar to both salt doming (solid state) and magmatic plume (liquid-to-solid state) tectonics, suggesting similar terrestrial analyses can provide estimates of the mass geometry and thickness of the deformed host rock units. The subsurface mobility of material produces surface deformation features such as fracture patterns and dome slopes that are unique to one geophysical processes or the other (or conversely, some characteristics are common to all domal forms), which provides constraints on the underlying geometry of the mobile material and the volume of displaced rock above. Using Dawn data, we are analyzing the domal uplift regions (and associated structures) on Ceres to constrain their surface volume, depth, and shape. Scaled physical analog experiments are being performed to constrain the underlying properties of the subsurface mass movement and resultant surface deformation patterns [3,4] for direct comparison to Ceres. Experiments to test the effects of a freezing lens of water and the mobility of low viscosity/low density materials are being explored as new results from the Dawn mission emerge.

[1] Buczkowski et al., 2016; [2] Ruesch et al., 2016; [3] Wyrick et al., LPSC 2019, #3239; [4] Hubbert, M.K., GSA Bull., 48 (10): 1459–1520, 1937. Research support from NASA’s Discovery Data Analysis program # 80NSSC17K0457.