Date of Award:

2014

Document Type:

Dissertation

Degree Name:

Doctor of Philosophy (PhD)

Department:

Geology

Advisor/Chair:

John Shervais

Abstract

The Snake River Plain (SRP) is one of the best-preserved examples of continental hotspot volcanis, with a continuous record of volcanism that extends over 16 Ma to the present. Yellowstone-Snake River Plain records the migration of plume-tail volcanism from inception at the Bruneau-Jarbridge caldera complex at 12.6 Ma to its present locus, under the Yellowstone Plateau.

Records kept by the Snake River Plain volcanic actions include rhyolite lavas and ignimbritesm minor coeval basalts, and an overlying veneer of younger basalts. The central SRP has received comparatively little attention in the past. The Kimama core hole was drilled as part of Project Hotspot, the Snake River Scientific Drilling Project, which seeks to understand the long-term volcanic and sediment logical history of the SRP volcanic province.

The Kimama core hole is the only part of the SRP that has not been scientifically drilled and cored to a significant depth in the past. Investigations of subsurface stratigraphy in continental volcanic provinces such as the SRP-YP are limited by the by the relatively low depth and spatial distribution of cored wells. The study of the Kimama core provides us with a continuous record of basalt and minor sediment deposition.

The long-term volcanic history of the SRP, documented by moving magma and its composition, demonstrates that magmatism is mantle plume-derived. Our investigation of the Kimama core, combined with new mantle tomography, provides evidence that refutes non-plume models for the origin of the Snake River Plain volcanic province.

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Geology Commons

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