Date of Graduation
Summer 2024
Degree
Master of Science, Geology
Department
Earth, Environment and Sustainability
Committee Chair
Gary Michelfelder
Abstract
The Mogollon-Datil volcanic field which is located in southwestern New Mexico, is the result of punctuated volcanism and the transition between arc and rift magmatism. The resurgent domes within the 28 Ma Bursum caldera records the transition from rhyolitic to basaltic andesite volcanism that occurred between 27-26 Ma. Using a combination of new zircon U-Pb ages using chemical abrasion isotope dilution thermal ionization mass spectrometry (CA-ID-TIMS) with zircon U-Pb geochronology and trace element contents by laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) and whole rock and mineral trace element contents and isotope geochemistry this study investigates the temporal and spatial relationship of the resurgent domes of the Bursum caldera. This study found that the Bloodgood Canyon Tuff (BCT), the caldera forming eruption, the Apache Spring Tuff (AST), the intra caldera fill, and the Fanney Rhyolite (FR), the main unit of the resurgent domes share crystallization ages of ~28.4 Ma show a continuous crystallization sequence from the same source reservoir. However, the whole rock geochemistry and stratigraphic analysis indicates that the AST erupted before the FR, where the source became more compositionally zoned over time, creating two end members of FR. Additionally, the Deadwood Gulch member of FR and the Rhyolite of Hay Canyon have ages significantly younger than the BCT, AST, and FR, and are sourced from a different reservoir. Geochemical analyses also suggest that the Deadwood Gulch member of the FR is made up of two distinct end members. A mixing model determined from Sr isotopes show the possible transition from ignimbrite eruptions to basaltic andesite eruptions, due to the continued injection of basalt into the source magma.
Keywords
zircon, geochronology, geochemistry, MDVF, New Mexico
Subject Categories
Geochemistry | Geology | Volcanology
Recommended Citation
Wagner, Ethan, "Million-Year Melt-Presence in Mogollon-Datil Volcanic Field Rhyolites: Constraining the Histories of the Bursum Caldera Resurgent Domes" (2024). MSU Graduate Theses/Dissertations. 4012.
https://bearworks.missouristate.edu/theses/4012
