Author ORCID Identifier:
Date of Graduation
12-2025
Document Type
Dissertation
Degree Name
Doctor of Philosophy in Space & Planetary Sciences (PhD)
Degree Level
Graduate
Department
Space & Planetary Sciences
Advisor/Mentor
Chevrier, Vincent
Committee Member
Ahrens, Caitlin
Second Committee Member
Wang, Feng
Third Committee Member
Kennefick, Julia
Fourth Committee Member
Roe, Larry
Fifth Committee Member
Madden, Megan Elwood
Keywords
Ceres Impact Processes; Clathrate Hydrates; Europa Impact Processes; Impact Processes; Planetary Simulation Experiments; Titan Impact Processes
Abstract
This work concerns solar system ices, particularly water ice and clathrate hydrates. Water ice is abundant as a mineral in the outer parts of the solar system, providing source material for the formation of clathrates. We explored constituents through a combination of numerical modeling and laboratory experiments. Understanding the differences and similarities between these materials can shed light on planetary habitability, composition, and evolution. Chapter one contains relevant background information. This chapter introduces the ices that will be studied and gives insight into the locations of interest within our solar system. It also explains the mechanics of impact cratering processes and the numerical modeling program used in many of the remaining chapters. Chapter two explores how impacts onto Europa’s ice shell may create networks of fractures connecting the surface to the subsurface ocean. Impact models on 9 km and 18 km of ice thickness are impacted by 0.25 km, 0.5 km, and 1.0 km impactors. The resulting damage is compared to determine the degree of interconnectedness between the top and bottom surfaces of the ice. Chapter three investigates the morphological differences between craters formed in water ice and methane clathrate materials. Five diameters of impactor are modeled striking both target materials. We compared the crater size and melt reservoirs created in each material. Chapter four used impact modeling to compare impact craters produced in mixed rock/clathrate material on the dwarf planet, Ceres. Water ice and methane clathrate are compared to two mixtures (90/10 and 70/30) of serpentine and clathrate. We compared the end crater features, including morphology measurements and melt chamber characteristics. Chapter five details our attempts to make clathrate hydrate samples in a planetary simulation chamber. This project secured NASA FINESST funding on the strength of preliminary data. Tragically, various mishaps prevented further experimentation. This chapter is a record of the chamber troubleshooting and rebuilding process. Chapter six contains a summary of findings and concluding remarks.
Citation
McDonald, J. R. (2025). Understanding Outer Solar System Ice Composition Through Impact Processes: Simulations and Hydrates. Graduate Theses and Dissertations Retrieved from https://scholarworks.uark.edu/etd/6032
