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ASU Electronic Theses and Dissertations


This collection includes most of the ASU Theses and Dissertations from 2011 to present. ASU Theses and Dissertations are available in downloadable PDF format; however, a small percentage of items are under embargo. Information about the dissertations/theses includes degree information, committee members, an abstract, supporting data or media.

In addition to the electronic theses found in the ASU Digital Repository, ASU Theses and Dissertations can be found in the ASU Library Catalog.

Dissertations and Theses granted by Arizona State University are archived and made available through a joint effort of the ASU Graduate College and the ASU Libraries. For more information or questions about this collection contact or visit the Digital Repository ETD Library Guide or contact the ASU Graduate College at gradformat@asu.edu.


Establishing the timing of impact crater formation is essential to exploring the relationship between bolide impact and biological evolution, and constraining the tempo of planetary surface evolution. Unfortunately, precise and accurate impact geochronology can be challenging. Many of the rock products of impact (impactites) contain relict, pre-impact phases that may have had their isotopic systematics completely reset during the impact event, only partially reset, or not reset at all. Of the many isotopic chronometers that have been used to date impactites, the U/Pb zircon chronometer (ZrnPb) seems least susceptible to post-impact disturbances, and ZrnPb dates are typically much more precise …

Contributors
Brunner, Anna Elizabeth, Hodges, Kip V, Barboni, Melanie, et al.
Created Date
2019

Primitive arc magmas provide a critical glimpse into the geochemical evolution of subduction zone magmas, as they represent the most unadulterated mantle-derived magmas observed in nature in these tectonic environments and are the precursors of the more abundant andesites and dacites typical in arcs. To date, the study of primitive arc magmas has largely focused on their origins at depth, while significantly less is known about pre-eruptive crustal storage and ascent history. This study examines the crustal storage and ascent history of the Mt. Shasta primitive magnesian andesite (PMA), the demonstrated dominant parent magma for the abundant mixed andesites erupted …

Contributors
Phillips, Mitchell, Till, Christy B, Hervig, Richard, et al.
Created Date
2019