Through geodynamic modeling, I investigate how Mars could have produced the extensive volcanism required to form the Tharsis rise early in its history, as well as continue to produce small amounts of melt up to present-day, in order to account for the evidence of limited geologically recent volcanism. InSight is the first interplanetary mission dedicated primarily to the study of a planet's deep interior, and has provided useful constraints for the present structure and interior temperature of Mars. I use the results from InSight and other spacecraft missions to more accurately model Mars, and evaluate the results of my geodynamic models, so as to constrain the properties that are necessary for or consistent with both the InSight results and the volcanic history reflected on the surface. This modeling has required extensive modification to the CitcomS geodynamic code I use, the bulk of that effort being in implementing and testing the melting calculations. One of the useful constraints that would have been provided by InSight would have been ground truthing the heat flow from the interior at the landing site, and this required determining, among other quantities, the thermal conductivity of the regolith into which the heat flow probe (mole) was placed. While the mole could not penetrate to its designed depth, thus disallowing the complete heat flow measurement, the team were able to obtain the necessary data determine the thermal conductivity, and how it varies seasonally. My rapid analytical method of estimating thermal conductivity produces results that agree surprisingly well with those of the team's complex numerical model, despite the mole not meeting the assumption of a sufficiently high length to width ratio. / Doctor of Philosophy / I investigate how Mars could have produced the extensive volcanism required to form the Tharsis rise early in its history, as well as continue to produce small amounts of melt up to present-day, in order to account for the evidence of limited geologically recent volcanism. I use 3D computer models of the mantle--the solid, but slowly flowing layer that makes up the bulk of rocky planets like Earth and Mars. InSight is the first interplanetary mission dedicated to the study of a planet's deep interior, and has provided useful constraints for the present structure and interior temperature of Mars. I use the results from InSight and other spacecraft missions to more accurately model Mars, and evaluate the results of my models, so as to constrain the properties that are necessary for or consistent with both the InSight results and the volcanic history reflected on the surface. This modeling has required extensive modification to the modeling code I use, the bulk of that effort being in implementing and testing the melting calculations. One of the useful constraints that would have been provided by InSight would have been ground truthing the heat flow from the interior at the landing site, and this required determining, among other quantities, the thermal conductivity of the soil into which the heat flow probe (mole) was placed. While the mole could not penetrate to its designed depth, thus disallowing the complete heat flow measurement, the team were able to obtain the necessary data determine the thermal conductivity, and how it varies seasonally. My rapid analytical method of estimating thermal conductivity produces results that agree surprisingly well with those of the team's complex numerical model, despite the mole not meeting the assumption of a sufficiently high length to width ratio.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/116215 |
| Date | 05 September 2023 |
| Creators | Murphy, Joshua |
| Contributors | Geosciences, King, Scott D., Caddick, Mark J., Weiss, Robert, Stamps, D. Sarah |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Language | English |
| Detected Language | English |
| Type | Dissertation |
| Format | ETD, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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