Ice Sheet Melting Throughout Mars Climate History: Mechanisms, Rates, and Implications

Scanlon, Kathleen E.

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Year:: 2016
Contributor:: Scanlon, Kathleen E (creator); Head, James (Director); Huang, Yongsong (Reader); Lee, Jung-Eun (Reader); Mustard, John (Reader); Fastook, James (Reader); Brown University. Geological Sciences (sponsor)
Genre:: theses
Subject:: Mars; Mars climate; Early Mars; Glaciovolcanism; Snowmelt; Mars (Planet)
Extent:: xx, 273 p.
DOI: https://doi.org/10.7301/Z0K072PS

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Abstract:: Valley networks, many connecting voluminous paleolakes, dissect the martian highlands, but ceased activity ~3.7 billion years ago. The nature of the climate that allowed so much water to flow across the surface of what is now a cold desert planet, and the road by which the climate evolved to its present state, comprise one of the longstanding mysteries of planetary science. The question of whether carving the valley networks required an Earthlike climate, with oceans and rainstorms, is considered particularly relevant to understanding whether microbial life arose on Mars. Even if there was life on ancient Mars, evidence is rare for long-lived aqueous (let alone habitable) surface environments in the last ~3 billion years of martian history. In this work, we investigate melting of snow and ice by greenhouse warming as an agent for fluvial erosion and a probe of early Martian climate conditions, and by lava-ice interactions as a mechanism for creating aqueous environments on Amazonian Mars. In Chapter 1, we modeled snowmelt rates under various warming scenarios for early Mars. We showed that snowmelt rates consistent with valley channel geomorphometry can occur with less greenhouse warming than comparable rainfall requires. In Chapter 2, we investigated the implications of a thicker atmosphere for the climate at the south pole of Mars. We found that greenhouse warming beyond that from CO2 is required for the ice sheet to reach the observed extent of the Dorsa Argentea Formation, and to induce basal melting in the regions of the former ice sheet where glaciofluvial features are observed. In Scanlon et al. (2014), we documented evidence for glaciovolcanic landforms across the Arsia Mons fan-shaped deposit (FSD). In Chapter 3, we investigated the effects of lava-ice interactions on glacial conditions recorded in the FSD, and reviewed microbial habitats in terrestrial glaciovolcanic settings. In Chapter 4, we documented additional glacial landforms in the FSD, and presented new geomorphologic evidence that ice from the Late Amazonian paleoglacier may remain buried in the FSD. In Chapter 5, we proposed tests for the “icy highlands” model for early Mars, and outlined ways to build on our results.
Notes:: Thesis (Ph.D. -- Brown University (2016)

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Rights: In Copyright
Restrictions on Use: Collection is open for research.

Citation

Scanlon, Kathleen E., "Ice Sheet Melting Throughout Mars Climate History: Mechanisms, Rates, and Implications" (2016). Earth, Environmental and Planetary Sciences Theses and Dissertations. Brown Digital Repository. Brown University Library. https://doi.org/10.7301/Z0K072PS

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Earth, Environmental and Planetary Sciences Theses and Dissertations

Theses and Dissertations for the Earth, Environmental and Planetary Sciences department.
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