Sheila SeamanMichael J. JercinovicLac, Don2024-04-262009-08-2420092009-0910.7275/966509https://hdl.handle.net/20.500.14394/47070Geologyoxygen fugacityMount St. HelensQuizapuKatmaiVTTSFe-XANESGeologyUsing the Oxidation State of Iron Plagioclase to Evaluate Magma Oxygen Fugacity: A micro-XANES Studythesis