Hotspot Motion during the Cenozoic and True Polar Wander across the Cretaceous-Paleogene Boundary
| dc.contributor.advisor | Gordon, Richard G | en_US |
| dc.creator | Gaastra, Kevin | en_US |
| dc.date.accessioned | 2023-01-03T22:34:30Z | en_US |
| dc.date.available | 2023-06-01T05:01:13Z | en_US |
| dc.date.created | 2022-12 | en_US |
| dc.date.issued | 2022-12-01 | en_US |
| dc.date.submitted | December 2022 | en_US |
| dc.date.updated | 2023-01-03T22:34:30Z | en_US |
| dc.description.abstract | The motion of Earth’s tectonic plates relative to sites of mid-plate or excessive plate boundary volcanism produce age-progressive chains of volcanoes. These hotspot volcanoes are thought to be caused by plumes of hot mantle material rising in the solid state from near the core-mantle boundary. These mantle plumes and the hotspot tracks they produce are one of the only records of the motion of Earth’s surface relative to its interior. Therefore, understanding how these mantle plumes move relative to each other and the deep mantle is paramount to understanding the nature of plate tectonics. Here I present methods of analysis of volcano locations and age dates and apply them to three prominent Pacific plate hotspot tracks (Hawaii, Louisville, and Rurutu). I find that motion between these hotspots is insignificant for the last 80 million years. Therefore the mantle plumes underlying these Pacific plate hotspots may be more stable in a convecting mantle than previously inferred. Rates of hotspot motion become more uncertain further back in Earth’s history. Here I combine a Monte Carlo inversion method with objectively assigned uncertainties of the trends of the young portions of global hotspot chains to place bounds on neotectonic (i.e., the past 5-10 million years) rates and directions of hotspot motion. I find that a non-zero but slow plate-motion perpendicular rate of merely 2–4 mm/yr is indicated when considering most or all global hotspots. Though the trends of the Marquesas and Comores hotspots are distinct outliers which may indicate more recent rapid motion. The Earth’s magnetic field also provides a reference for the absolute motion of Earth’s tectonic plates. As over long time scales (>100,000 years) the Earth’s magnetic pole averages to the location of its axis of rotation. By analyzing the phase of marine magnetic anomaly C27r in the Pacific Ocean Basin I estimate the location of the Earth’s axis of rotation during the formation of this seafloor (63 million years ago). I use this to test hypotheses of true polar wander, a re-orientation of Earth’s crust and mantle relative its axis of rotation across the Cretaceous-Paleogene boundary. | en_US |
| dc.embargo.terms | 2023-06-01 | en_US |
| dc.format.mimetype | application/pdf | en_US |
| dc.identifier.citation | Gaastra, Kevin. "Hotspot Motion during the Cenozoic and True Polar Wander across the Cretaceous-Paleogene Boundary." (2022) Diss., Rice University. <a href="https://hdl.handle.net/1911/114192">https://hdl.handle.net/1911/114192</a>. | en_US |
| dc.identifier.uri | https://hdl.handle.net/1911/114192 | en_US |
| dc.language.iso | eng | en_US |
| dc.rights | Copyright is held by the author, unless otherwise indicated. Permission to reuse, publish, or reproduce the work beyond the bounds of fair use or other exemptions to copyright law must be obtained from the copyright holder. | en_US |
| dc.subject | Mantle Plumes | en_US |
| dc.subject | Hotspot Motion | en_US |
| dc.subject | Paleomagnetism | en_US |
| dc.subject | True Polar Wander | en_US |
| dc.title | Hotspot Motion during the Cenozoic and True Polar Wander across the Cretaceous-Paleogene Boundary | en_US |
| dc.type | Thesis | en_US |
| dc.type.material | Text | en_US |
| thesis.degree.department | Earth, Environmental and Planetary Sciences | en_US |
| thesis.degree.discipline | Natural Sciences | en_US |
| thesis.degree.grantor | Rice University | en_US |
| thesis.degree.level | Doctoral | en_US |
| thesis.degree.name | Doctor of Philosophy | en_US |
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