Description
- Abstract:
- The poles of Mercury and the Moon both show evidence for water ice, but there are distinct differences in the abundance and purity of the ice. Ice on Mercury is several meters thick and modeled to be ~95 wt. % pure water ice. In contrast, ice on the Moon appears to resemble a patchy frost that is compositionally heterogeneous. In this dissertation, we explore how differences in the abundance and purity of ice at Mercury and the Moon may be related to the ages, sources, and space-weathering histories of the ice. In Chapter 1, we derive ages of Mercury’s polar deposits from combined analyses of Poisson statistics and the first direct observations of crater densities within permanently shadowed ices imaged by the MESSENGER spacecraft. Our age estimates (10’s-100’s Myr) imply that the ice surfaces have been recently refreshed by a young impact(s) (Deutsch et al., 2019, EPSL). In Chapter 2, we derive ages of south polar craters on the Moon and find that the majority of surface ice is contained in old craters ≥∼3.1 Gyr. We analyze the dated craters and distribution of surface ice to constrain the age of post-true polar wander hydrogen emplacement and possible sources of surface ice (Deutsch et al., 2020, Icarus). In Chapter 3, we quantify the surface roughness of small ice-bearing craters on the Moon as a proxy for crater age, and identify surface ice within pre-Imbrian craters, although no ice-bearing craters are found within the Copernican-only domain in roughness space. (Deutsch et al., accepted, GRL). In Chapter 4, we assess the possibility that widespread volcanism on Mercury contributed to short-term atmospheres and polar ice deposits (Deutsch et al., in review). In Chapter 5, we quantify temperature-dependent changes in the normal albedo of the lunar surface at 1064 nm and discuss how temperature should be accounted for in future measurements of surface frost and ice on airless bodies (Deutsch et al., accepted, JGR: Planets). Finally, we synthesize the many findings of our work to provide forward thinking on science opportunities at the poles of Mercury and the Moon enabled by robotic and human exploration.
- Notes:
- Thesis (Ph. D.)--Brown University, 2020
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Citation
Deutsch, Ariel N.,
"Water Cycles of Mercury and the Moon: Sources, Evolution, and Current States of Polar Volatiles"
(2020).
Earth, Environmental and Planetary Sciences Theses and Dissertations.
Brown Digital Repository. Brown University Library.
https://doi.org/10.26300/h3pc-4g25
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Earth, Environmental and Planetary Sciences Theses and Dissertations
Theses and Dissertations for the Earth, Environmental and Planetary Sciences department....