D/H ratios and H2O contents record degassing and rehydration history of rhyolitic magma and pyroclasts

Hydrogen Isotope Composition of a Large Silicic Magma Reservoir Preserved in Quartz‐Hosted Glass Inclusions of the Bishop Tuff Plinian Eruption

“…(1983); white diamonds are Medicine Lake from Giachetti et al. (2020); white circles and triangles are Chaitén and Cordón Caulle, respectively, from Castro et al. (2014); and white squares are Mazama from Mandeville et al.…”

“…Meteoric waters infiltrate and modify the composition of volcanic glass following eruptive emplacement on timescales of <10–10 4 years (Cassel & Breeker, 2017; Giachetti et al., 2020; Nolan & Bindeman, 2013; Seligman et al., 2018). The meteoric water modifies the primary magmatic hydrogen isotope composition initially preserved in volcanic glass because meteoric waters are enriched in D relative to H, with the ratio controlled by precipitation, temperature, latitude, and altitude (e.g., Cassel et al., 2009; Giachetti et al., 2020, 2015; Hudak & Bindeman, 2018; Ingraham & Taylor, 1991; Jackson et al., 2019; Seligman et al., 2016). Meteoric water and groundwater in the vicinity of Long Valley have δ D in the range of −90‰ to −110‰, values enriched in H relative to D as expected on the rain shadowed, high‐altitude eastern flank of the Sierra Nevada (Friedman et al., 2002; Ingraham & Taylor, 1991).…”

“…Obsidian clasts in pyroclastic air‐fall deposits have been shown to contain an array of volatile contents. Those clasts are typically interpreted to represent syn‐eruptively quenched parcels of magma, whose individual volatile contents record snapshots of eruptive degassing at variable depths (Castro et al., 2014; Dunbar & Kyle, 1992; Giachetti et al., 2020; Newman et al., 1988; Rust et al., 2004; Taylor et al., 1983). Populations of such clasts from single eruptions typically display open‐system Rayleigh degassing trends marked by decreasing D/H values with decreasing H 2 O concentrations (e.g., Taylor et al., 1983) (compilation of all published obsidian chips in Figure 8).…”

“…Meteoric waters infiltrate and modify the composition of volcanic glass following eruptive emplacement on timescales of <10-10 4 years (Cassel & Breeker, 2017;Giachetti et al, 2020;Nolan & Bindeman, 2013;Seligman et al, 2018). The meteoric water modifies the primary magmatic hydrogen isotope composition initially preserved in volcanic glass because meteoric waters are enriched in D relative to H, with the ratio controlled by precipitation, temperature, latitude, and altitude (e.g., Cassel et al, 2009;Giachetti et al, 2020Giachetti et al, , 2015Hudak & Bindeman, 2018;Ingraham & Taylor, 1991;Jackson et al, 2019;Seligman et al, 2016). Meteoric water and groundwater in the vicinity of Long Valley have δD in the range of −90‰ to −110‰, Newman et al (1988); gray triangles are Mono Craters from J. D. Barnes et al (2014a); gray squares are Mono-Inyo Craters from Taylor et al (1983); gray diamonds are Medicine Lake from Taylor et al (1983); white diamonds are Medicine Lake from Giachetti et al (2020); white circles and triangles are Chaitén and Cordón Caulle, respectively, from Castro et al (2014); and white squares are Mazama from Mandeville et al (2009).…”

“…Datasets compiled for use in this paper are available in the in-text references and are summarized here: Pyroclastic obsidians are from J. D Barnes et al (2014a), Castro et al (2014), Giachetti et al (2020), Mandeville et al (2009), Newman et al (1988), and Taylor et al (1983); Basaltic melt inclusions are from Bouvier et al 2010…”