The role of volcanism in the early history of the Moon and Mercury

Whitten, Jennifer

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Year:: 2014
Contributor:: Whitten, Jennifer (creator); Head, James (Director); Hess, Paul (Reader); Pieters, Carle (Reader); Saal, Alberto (Reader); Blewett, David (Reader); Brown University. Geological Sciences (sponsor)
Genre:: theses
Subject:: Mercury; cryptomaria; intercrater plains; Geology; Volcanism; Moon; Mercury (Planet)
Extent:: 18, 405 p.
DOI: https://doi.org/10.7301/Z0CV4G3R

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Abstract:: Ancient volcanic deposits on terrestrial planetary bodies preserve a record of the early stages of planetary evolution, revealing important information about both the interior evolution and the surface modification history of planetary bodies. The work presented in this dissertation has mapped ancient volcanic deposits on the Moon (cryptomaria) and Mercury (intercrater plains) and measured their physical characteristics using remote orbital datasets to understand better the distribution and flux of volcanic materials onto these planetary surfaces. Initially, the character of how volcanic flows fill cratered terrain was modeled using high-resolution topography data in three different geologic settings in order to develop criteria for identifying the distribution and thickness of ancient volcanic deposits. Areal extents and map patterns can be used to predict volcanic deposit thicknesses. These expected morphologies for volcanic deposits and the latest available lunar datasets were used to establish the criteria necessary to distinguish cryptomaria from basin ejecta deposits. Eighteen cryptomaria regions were identified; all cluster on the nearside, with the largest deposits associated with impact basins. After identification, the mineralogy and composition of cryptomaria were measured to determine if these deposits are actually composed of mare basalts. Mineralogic modeling was combined with elemental analyses to assess which of the early igneous rocks could comprise the cryptomaria. The results of mineralogic modeling and compositional analyses of thorium and iron abundances indicate that the mapped cryptomaria are mare basalts. On Mercury, the origin of the intercrater plains was investigated to determine the role of volcanism during the planet’s early history. Ten areas of intercrater plains were evaluated to re-characterize the unit and produce a geologic map covering ~20% of the surface. Analysis of the stratigraphic relationships and evaluation of the basin impact ejecta origin led to the conclusion that the intercrater plains are formed by volcanic processes. Then, the importance of basin ejecta on Mercury was evaluated by analyzing the plains around Rembrandt basin. Evaluation of the ages, color properties, and distribution of the circum-Rembrandt plains indicate that the low albedo exterior plains are dominantly impact melt produced during the basin-formation event.
Notes:: Thesis (Ph.D. -- Brown University (2014)

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

Citation

Whitten, Jennifer, "The role of volcanism in the early history of the Moon and Mercury" (2014). Earth, Environmental and Planetary Sciences Theses and Dissertations. Brown Digital Repository. Brown University Library. https://doi.org/10.7301/Z0CV4G3R

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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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