3,4- 1Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA (mallory.kinczyk@jhuapl.edu)
- 2United States Geological Survey, Astrogeology Team, Flagstaff, AZ, USA
- 3National Air and Space Museum, Smithsonian Institution, Washington, D. C., USA
- 4The University of Texas at Austin, Austin, TX, USA
The complexity of Enceladus’ surface and the presence of young, heavily tectonized regions such as the South Polar Terrain make it a compelling exploration target for understanding icy satellite evolution and potential habitability. However, the current gap in our understanding of Enceladus’s thermal history limits our ability to constrain the longevity of its internal ocean and timescales of endogenic geologic activity. In contrast to the tectonized terrains, Enceladus’ ancient, heavily cratered surfaces preserve the earliest geologic events and preserve potential evidence of Enceladus’ thermal and geophysical history. Characterizing geologic features within the cratered terrains provides observation-based insight into the long-term evolution of the ice shell and can place constraints on the evolution of tidal stresses and heat flow affecting the surface geology.
Many craters within the cratered terrains appear to have undergone viscous relaxation, where their depths are shallower than what is expected for fresh craters and can be attributed to elevated heat flow in the subsurface [1]. Global models of present-day heat flux indicate that there are spatial variations in heat flow across the ice shell [2]. However, these models are a snapshot in time and do not represent temporal variations. Observational studies of the cratered terrains have found evidence of extreme viscous relaxation in regions where modeled present-day heat flux is relatively low [3], although these correlations have not been systematically analyzed.
Most, if not all, large craters on Enceladus show some degree of viscous relaxation with shallow floors and large central mounds. We present on the compilation of a global database of impact craters on Enceladus and how this data product feeds into our systematic campaign to identify signs of crater relaxation across Enceladus’ heavily cratered terrains. These data will feed into a larger effort to use the spatial distribution of relaxed craters and models of crater relaxation to gain insight into the thermal history of the cratered terrains. In comparing the distribution of relaxed craters to models of present-day heat flux, we may determine whether these models are sufficient to explain the observed relaxation states of craters and, in turn, whether there is observational evidence that Enceladus has experienced one or more past episodes of elevated heat flux.
References:
[1] Bland, M. T., Singer, K. N., McKinnon, W. B., & Schenk, P. M. (2012). Enceladus' extreme heat flux as revealed by its relaxed craters. Geophysical Research Letters, 39(17), [2] Hemingway, D. J., & Mittal, T. (2019). Enceladus's ice shell structure as a window on internal heat production. Icarus, 332, 111-131, [3] Kinczyk, M. J., Byrne, P. K., & Patterson, G. W. (2024). The Geological History of Enceladus' Cratered Terrains. Journal of Geophysical Research: Planets, 129(7), e2024JE008326.
How to cite: Kinczyk, M., Beddingfield, C., Bland, M., Martin, E., and Hemingway, D.: Early results on the global distribution of relaxed craters on Enceladus, EPSC-DPS Joint Meeting 2025, Helsinki, Finland, 7–12 Sep 2025, EPSC-DPS2025-1176, https://doi.org/10.5194/epsc-dps2025-1176, 2025.
