The thermal history of the Earth, from planetary accretion and core differentiation up to the present time, is of paramount importance for understanding our planet. The thermal evolution of the core and the mantle dictate the generation of the Earth's internal magnetic field and its evolution through time. In this dissertation, I study scenarios for the thermal and magnetic evolution of the Earth, using numerical simulations for mantle convection and implementing recent geochemical models for the mantle and core. The conditions for which a magnetic field can be generated in the Earth's core are studied using parameterized models for energy and entropy. The model devised in this project couples the results of the numerical simulations with the parameterized models for the core, to produce a global thermal and magnetic history, with feed-back between events happening in the mantle and the core.<p>
The dissertation presents an analysis of the scenarios that can be constructed from implementing new constraints into the thermal models for the mantle and core and emphasizes the most relevant scenarios which can be applied to the Earth's evolution, consistent with physical parameters, and geochemical and magnetic constraints known to date. In addition, I discuss the relevance of some of the scenarios which appear incompatible with the Earth's evolution, but are reminiscent of the evolution of other terrestrial bodies.<p>
The results of this work show that the most successful scenarios for the thermal and magnetic evolution require the presence of small amounts of core internal heating in the form of radioactive potassium, or a slightly increased concentration of radioactive elements at the base of the mantle, due to isolated, if the base of the mantle is less mobile and acts as a thermal insulator between the core and the overlying convective mantle primordial reservoirs. Successful scenarios are also obtained if the base of the mantle is less mobile and acts as a thermal insulator between the core and the overlying convective mantle. If the base of the mantle is less mobile and acts as a thermal insulator between the core and the overlying convective mantle.
| Identifer | oai:union.ndltd.org:USASK/oai:usask.ca:etd-04272009-120346 |
| Date | 27 April 2009 |
| Creators | Costin , Simona Eugenia Otilia |
| Contributors | Merriam, James B., Kerrich, Robert, Jellinek, Mark, Butler, Samuel L., Ansdell, Kevin M., Pan, Yuanming |
| Publisher | University of Saskatchewan |
| Source Sets | University of Saskatchewan Library |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://library.usask.ca/theses/available/etd-04272009-120346/ |
| Rights | restricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University of Saskatchewan or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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