Wallace, PaulFulton, Anne2019-09-182019-09-182019-09-18https://hdl.handle.net/1794/24959To investigate the late-stage dynamics of the eruption of a compositionally and thermally zoned magma body, we targeted crystal-scale features in the stratigraphically latest fall unit (F9) of the 0.765 Ma Bishop Tuff. Spatial and temporal connections between the crystal-poorer, more-evolved ignimbrite to the east of Long Valley caldera and the crystal-richer, less-evolved ignimbrites to the north remain debated. From F9, we present major and trace elements and volatile data from quartz-hosted melt inclusions (MI) and matrix glasses, plus cathodoluminescence images and diffusion models of quartz phenocrysts. MI and textural data demonstrate that unit F9 is the fall equivalent of the northern and eastern ignimbrite lobes. This result confirms that these major ignimbrite packages, once considered sequential, were erupted coevally. The compositional record from MIs and crystal zoning in F9 implies the presence of multiple inputs of less evolved magmas to the system centuries to millennia before eruption. Major and trace element abundances for MIs and matrix glasses are included in a supplemental file.en-USAll Rights Reserved.Bishop TuffDiffusionIgnimbriteMelt InclusionVolatilesElectronic Thesis or Dissertation