Identifier

etd-07102017-134825

Degree

Master of Science (MS)

Department

Geology and Geophysics

Document Type

Thesis

Abstract

A major knowledge gap exists on how eruptive compositions of a single martian volcanic province change over time. The Elysium Volcanic Province is a location of great geologic interest on Mars. Its predominantly Amazonian surface age (beginning 3.3 Ga), and its isolation in the northern hemisphere of Mars away from other volcano-tectonic regions, make it an ideal locale to investigate igneous compositions erupted during the most recent geologic period on Mars. Here, this work seeks to fill that gap by assessing the compositional evolution of Elysium as a major martian volcanic province in two related projects. The first project seeks to characterize and contrast different portions of the Elysium Volcanic Province chronologically, morphologically, and geochemically, in order to establish evidence for spatio-temporal magmatic evolution across the province. This study is additional motivated by a unique geochemical signature which overlaps with the southeastern flows of this volcano. The geochemical and temporal differences between the SE and NW lava fields are interpreted to be consistent with primary magmatic processes, such as a change in depth of melt formation within the martian mantle due to crustal loading and lithospheric flexure. In the second project, the petrologic modeling software pMELTS is used to simulate the partial melting of the martian mantle. By using a range of possible initial conditions and comparing the corresponding model outcomes to geochemistry on the surface --as derived from the Gamma-ray and Neutron Spectrometer (GRS)-- the mantle conditions of the magma source are constrained for each portion of the Elysium Volcanic Province. The geochemistry of the Elysium Volcanic Province is consistent with liquid compositions produced by 10-20% partial melting for all three sub-regions and pressures are estimated to be between 17 and 21 kbars for Central Elysium, between 17 and 19 kbars for NW Elysium, and between 14 and 16 kbars for SE Elysium. These pressures correspond to depths of melt formation that are consistent with independently calculated thicknesses of the Elysium lithosphere.

Date

2017

Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

Karunatillake, Sunit

DOI

10.31390/gradschool_theses.4456

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