Date of Award
12-1-2018
Degree Name
Doctor of Philosophy
Department
Geology
First Advisor
Ferré, Eric
Abstract
The Middle-Upper Jurassic sedimentary rocks (i.e., the Entrada Sandstone, Wanakah Formation, and Morrison Formation) in western Colorado were mostly deposited in the Paradox Basin and form part of the modern-day Colorado Plateau in the Cordilleran foreland region. These rocks were deposited in the Mesozoic during periods of active tectonic processes in western and eastern Laurentia due to the Cordilleran magmatism and continued rifting of Pangaea, respectively. The Middle-Late Jurassic sedimentary record in the Paradox Basin shows rapid transition in depositional environments, pulses in sedimentation, post-depositional alteration, and changes in provenance. This dissertation project utilizes three main scientific tools to address pertinent geologic questions regarding the stratigraphic evolution of these units in the Paradox Basin. U-Pb detrital zircon geochronology of sandstones from these units show local and distal provenance sources. The anisotropy of magnetic susceptibility (AMS) of sediments and rock magnetism attribute the post-depositional alteration to percolation of ferruginous fluids driven by an adjacent regional uplift. Multi-geochemical proxies in paleosols suggest variable redox conditions, and a sub-humid to humid paleoclimate with seasonal precipitation during sedimentary hiatus in the Paradox Basin.
Access
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