Description
- Abstract:
- A primary motivation for exploring Mars is its likeness to Earth; in particular, the fact it had flowing water once on its surface. Studying the climate and climate-related processes of Mars provides comparative planetological insights about the fate of the evolution under different astronomical extremes than Earth. Today, liquid water is not stable on Mars' surface, but water in the form of ice is. The largest surface reservoirs of water ice are the north and south polar ice caps. Analogous to ice sheets and ice cores on Earth, these caps are composed of icy and dusty beds whose ratio likely reflects temporal variability in ice stability and dust deposition linked to climate states. This dissertation focuses on the upper 500 m of the North Polar Layered Deposits (NPLD) exposed at the surface within the north polar spiral troughs. Despite decades of investigations, compositional variability between the layers and their connection to climate-driven accumulation processes remains ambiguous due to the superposition of modern aeolian surface processes, which modify the surface composition and topography (i.e., trough wall erosion, sublimation, redistribution of dust and ice, and dust-veneer formation and induration). The main objective of this dissertation is to characterize and detangle the present-day surface modification processes and those that reflect paleo-accumulation processes through topographic expression, spectrally derived composition, and numerical geophysical modeling. The results of the dissertation have two main findings. 1) Spatio-temporal changes in terrain slope and surface dust cover over just several km greatly influences the amount of ice loss from the polar troughs. Additionally, the ice loss (solely from differential sublimation modulated by lag build-up and removal) would have likely occurred between 60–125 kya and as fast as 1–25 kyr within that timeframe. 2) Comparison of spectrally derived surface composition of the NPLD between two different outcrops shows that the surface composition reflects a mixture of local paleo-condition variability during layer accumulation and the variability in modern-day post-depositional processes. Ultimately, this dissertation takes a step towards further deciphering the cap’s complex evolution and emphasizes the need for data integration to reveal the environment recorded within.
- Notes:
- Thesis (Ph. D.)--Brown University, 2021
Citation
Pascuzzo, Alyssa Christine,
"Detangling the processes recorded in ice: Geomorphic and hyperspectral analysis of Mars’ north polar spiral troughs"
(2021).
Earth, Environmental and Planetary Sciences Theses and Dissertations.
Brown Digital Repository. Brown University Library.
https://repository.library.brown.edu/studio/item/bdr:rk8dthvz/
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Earth, Environmental and Planetary Sciences Theses and Dissertations
Theses and Dissertations for the Earth, Environmental and Planetary Sciences department....