High-Resolution Pacific Apparent Polar Wander Since the Paleocene: Evidence for Two Episodes of True Polar Wander and Two True Polar Stillstands

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dc.contributor.advisorGordon, Richard Gen_US
dc.contributor.committeeMemberde Hoop, Maartenen_US
dc.creatorWoodworth, Danielen_US
dc.date.accessioned2022-09-23T18:18:32Zen_US
dc.date.created2022-08en_US
dc.date.issued2022-08-11en_US
dc.date.submittedAugust 2022en_US
dc.date.updated2022-09-23T18:18:32Zen_US
dc.descriptionEMBARGO NOTE: This item is embargoed until 2024--08-01en_US
dc.description.abstractPaleomagnetic poles from the continents have long provided evidence for apparent polar wander (APW), the motion over geologic time of the spin axis relative to a continent or tectonic plate. In contrast, the APW paths of oceanic plates are much less developed, mainly because oceanic plates lack subaerially exposed surface, making conventional paleomagnetic approaches difficult or impossible. Herein two alternative approaches, skewness analysis of marine magnetic anomalies and paleo-spin axis estimation from the distribution of paleo-equatorial sediment bands, are developed and applied. With these approaches we determined a high-resolution APW path for the Pacific Plate from 56 Ma to 12 Ma. Combined with existing Pacific poles for 72 Ma to 58 Ma, our Pacific APW allows study of finer detail than is possible using conventional methods. We identify two tracks in the Pacific APW path, suggesting northward plate motion relative to the spin axis 72 Ma to 56 Ma and 46 Ma to 12 Ma. Surprisingly, there is no net apparent polar wander between 12 Ma and the present and during the gap between these tracks southward motion from 56 Ma to 46 Ma is indicated. When reconstructed into the reference frame of the Pacific hotspots, which has been used to approximate an absolute reference frame, the two Pacific APW tracks correspond to two stillstands in the motion of the paleo-spin axis at locations significantly different both from one another and the present spin axis. These locations are separated by spin axis motion from 56 to 46 Ma and 12 Ma to the present. We interpret these stillstands in paleo-spin axis motion relative to the Pacific hotspots as true polar stillstands and the intervals separating them, corresponding to anomalous Pacific APW, as episodes of true polar wander of 7° and 3°, respectively.en_US
dc.embargo.lift2024-08-01en_US
dc.embargo.terms2024-08-01en_US
dc.format.mimetypeapplication/pdfen_US
dc.identifier.citationWoodworth, Daniel. "High-Resolution Pacific Apparent Polar Wander Since the Paleocene: Evidence for Two Episodes of True Polar Wander and Two True Polar Stillstands." (2022) Diss., Rice University. <a href="https://hdl.handle.net/1911/113270">https://hdl.handle.net/1911/113270</a>.en_US
dc.identifier.urihttps://hdl.handle.net/1911/113270en_US
dc.language.isoengen_US
dc.rightsCopyright 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.subjectPaleomagnetismen_US
dc.subjecthotspotsen_US
dc.subjectskewness analysisen_US
dc.subjectPacificen_US
dc.subjecttectonicsen_US
dc.titleHigh-Resolution Pacific Apparent Polar Wander Since the Paleocene: Evidence for Two Episodes of True Polar Wander and Two True Polar Stillstandsen_US
dc.typeThesisen_US
dc.type.materialTexten_US
thesis.degree.departmentEarth Scienceen_US
thesis.degree.disciplineNatural Sciencesen_US
thesis.degree.grantorRice Universityen_US
thesis.degree.levelDoctoralen_US
thesis.degree.nameDoctor of Philosophyen_US
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