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Leonard, Tiffany F. 2015-07-22T22:17:49Z 2015-07-22T22:17:49Z 2015-05 2015-04-29 2015-5 Origin of the Yellowstone hotspot system remains debated. Proposed hypotheses fall into two main categories that involve either a deep mantle plume or only upper mantle processes. Recent seismic tomography images suggest the existence of hot mantle upwelling beneath the present-day Yellowstone, lending support to the plume hypothesis. However, the effect of the Farallon slab on the temporal evolution of the hypothesized plume remains unclear. We use 4-D geodynamic models to investigate the temporal evolution of slab-plume interaction on the formation of the intra- plate volcanic province that includes the mid-Miocene Columbia River flood basalt (CRFB) and subsequent Yellowstone and Newberry hotspot tracks. We find that the sinking slabs dominate the buoyancy and dynamics of the system, and that evolution of the mantle upwelling is subject to that of the slabs. Our best-fit model with a hot upwelling starting at 35 Ma below the present-day Yellowstone can match both the mid-Miocene flood basalt event and the present-day lower mantle seismic image, suggesting a possible contribution of deep mantle to the CFRB. However, all models predict very little upper mantle residual hot anomaly, in contrast to the voluminous slow seismic anomalies, especially beneath the Snake River Plain. These models also fail to generate a vertical plume conduit below Yellowstone as suggested by seismic tomography. We conclude that additional mechanisms must be responsible for adding more heat to the western U.S. upper mantle. Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2015-07-22 without embargo terms The student, Tiffany Leonard, accepted the attached license on 2015-04-27 at 14:16. The student, Tiffany Leonard, submitted this Thesis for approval on 2015-04-27 at 14:22. This Thesis was approved for publication on 2015-04-29 at 10:17. DSpace SAF Submission Ingestion Package generated from Vireo submission #8125 on 2015-07-22 at 10:34:08 Made available in DSpace on 2015-07-22T22:17:49Z (GMT). No. of bitstreams: 2 LEONARD-THESIS-2015.pdf: 3263566 bytes, checksum: 3a70c69352f7de1323ae6327bb3630ce (MD5) LICENSE.txt: 4212 bytes, checksum: 95e206f29d778c198746badbb1905b84 (MD5) Previous issue date: 2015-04-29 application/pdf http://hdl.handle.net/2142/78510 en Copyright 2015 Tiffany Leonard Yellowstone plume geodynamics Testing the hypothesis of the slab-plume interaction on the formation of the Yellowstone hotspot system text text Geology Geology University of Illinois at Urbana-Champaign Thesis M.S.