Growth and textural evolution during crystallization of quartz and feldspar in hydrous, rhyolitic melt

Rusiecka, Monika K.; Baker, Don R.

doi:10.1007/s00410-021-01809-1

Cited by 8 publications

(12 citation statements)

References 40 publications

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“…The growth rates we examine here are generally on the fast side of the spectrum of the average growth rates over the entire history of magma storage estimated with erupted samples (Gualda & Sutton, 2016; Gualda et al., 2012; Pamukçu et al., 2015; Seitz et al., 2016). The growth rates in our simulations are more consistent with those measured in crystal‐growth experiments, which are conducted at similar time scales of our model and with enforced undercooling ranging from 20 to 200 K (Baker & Freda, 2001; Maneta & Anderson, 2018; Rusiecka & Baker, 2021; Sirbescu et al., 2017).…”

Section: Methodssupporting

confidence: 86%

Deciphering Clues Regarding Magma Composition Encoded in Quartz‐Hosted Embayments and Melt Inclusions Through Direct Numerical Simulations

Wei,

Ruefer,

Pamukcu

et al. 2024

JGR Solid Earth

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Crystal‐hosted melt embayments and melt inclusions partially record magmatic processes at depth, but it is not always obvious how to interpret this record. One impediment is our incomplete understanding of how embayments and melt inclusions form. In this study, we investigate the formation mechanism of embayments and melt inclusions during quartz growth to quantify the relationship between the compositions of the entrapped and average melt. We study the growth of embayments and inclusions through direct numerical simulations that couple the growth of a crystal surface with the evolution of the concentrations of incompatible components in the surrounding melt. We find that H2O is more enriched in the interior of defects on crystal surface compared to the exterior. The resultant lower disequilibrium in the defect interior causes lower growth rate than in the exterior, elongating the defect into an embayment. If crystal growth stops, the composition in the embayment equilibrates with the average melt within days to months. If crystal growth continues until the embayment neck closes, a melt inclusion forms. The melt entrapped by both embayments and melt inclusions is enriched in incompatible components, such as H2O and CO2. In addition to inclusion size, the enrichment of incompatible components in melt inclusions also depends on component diffusivity and the crystal growth regime. High‐diffusivity components like H2O have similar enrichment levels in all scenarios, while lower‐diffusivity components like CO2 are more enriched in melt inclusions with smaller sizes or formed in continuous crystal growth.

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Section: Methodssupporting

confidence: 86%

Deciphering Clues Regarding Magma Composition Encoded in Quartz‐Hosted Embayments and Melt Inclusions Through Direct Numerical Simulations

Wei,

Ruefer,

Pamukcu

et al. 2024

JGR Solid Earth

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“…% on an anhydrous basis: 75.7 SiO2, 0.1 TiO2, 13.2 Al2O3, 0.7 FeO, 0.1 MnO, 0.1 MgO, 0.6 CaO, 4.3 Na2O, 5.1 K2O; Maneta and Baker 2014). This is the same material as used to investigate cooling-induced crystallization by Rusiecka et al (2020) and Rusiecka and Baker (2021). The obsidian was coarsely crushed and melted at 1400 °C for 4 hours before being ground to a fine powder.…”

Section: Methodsmentioning

confidence: 99%

Nucleation delay in water-saturated rhyolite during decompression in shallow volcanic systems and its implications for ascent dynamics

Rusiecka

Martel

2022

Bull Volcanol

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We developed a model of feldspar nucleation delay during decompression in water-saturated rhyolite based on classical nucleation theory (CNT). With the thermodynamic and kinetic parameters proposed in this study, the model agrees with the experimental results of this study to within a factor of two. To account for the variety of conditions encountered by magma during ascent, we propose expanding the model, developed in this study for isothermal decompression, to a wider range of pressures and temperatures (i.e., non-isothermal conditions). We present new measurements of feldspar growth rates during decompression in water-saturated rhyolite, emphasizing the importance of accurately calculating the nucleation delay in order to estimate growth rates. Using these data, we propose a method for estimating the ascent rate of water-saturated rhyolite based on the nucleation delay of feldspar microlites.The findings of this study hold the promise of a better understanding of volcanic timescales during magma ascent in the conduit, as well as the possibility of extending our model to more complicated scenarios with changing pressure and temperature.

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“…Using an iris aperture, the laser spot size was gradually increased for a complete excavation of the inclusion material without fracturing the hosting quartz crystal. The following isotopes were chosen to analyze with a dwell time of 2-20 ms: 7 Li, 11 B, 23 Na, 32 S, 35 Cl, 39 K, 55 Mn, 57 Fe, 63 Cu, 66 Zn, 71 Ga, 73 Ge, 75 As, 79 Br, 85 Rb, 88 For external standardization to calculate the element ratios, we used a standard reference material (SRM) of a fused synthetic glass of NIST 610 [41] and a natural scapolite mineral of Sca-17 [42,43] for S, Cl, and Br. For internal standardization, we used an estimated Na concentration from microthermometry [44] for the brine inclusions and an average Al 2 O 3 content of 14 ± 1 wt.% in the Sannae-Eonyang granite [26,36,37] for the melt inclusions.…”

Section: La-icp-msmentioning

confidence: 99%

“…These low temperatures suggest a significant undercooled disequilibrium during UST formation in granite. Skeletal textures such as granophyric texture and UST occurring in the pegmatitic and aplitic granites are evidence of strong undercooling [73][74][75][76].…”

Section: Magmatic Fluid Exsolution and P-t Evolution During The Eonyang Ust Formationmentioning

confidence: 99%

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Periodically Released Magmatic Fluids Create a Texture of Unidirectional Solidification (UST) in Ore-Forming Granite: A Fluid and Melt Inclusion Study of W-Mo Forming Sannae-Eonyang Granite, Korea

et al. 2021

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The Upper Cretaceous Sannae-Eonyang granite crystallized approximately 73 Ma and hosted the Sannae W-Mo deposit in the west and the Eonyang amethyst deposit in the east. The granite contained textural zones of miarolitic cavities and unidirectional solidification texture (UST) quartz. The UST rock sampled in the Eonyang amethyst mine consisted of (1) early cavity-bearing aplitic granite, (2) co-crystallization of feldspars and quartz in a granophyric granite, and (3) the latest unidirectional growth of larger quartz crystals with clear zonation patterns. After the UST quartz was deposited, aplite or porphyritic granite was formed, repeating the prior sequence. Fluid and melt inclusions occurring in the UST quartz and quartz phenocrysts were sampled and studied to understand the magmatic-hydrothermal processes controlling UST formation and W-Mo mineralization in the granite. The composition of melt inclusions in the quartz phenocrysts suggested that the UST was formed by fractionated late-stage granite. Some of the melt inclusions occurring in the early-stage UST quartz were associated with aqueous inclusions, indicating fluid exsolution from a granitic melt. Hypersaline brine inclusions allowed the calculation of the minimum trapping pressure of 80–2300 bars. Such a highly fluctuating fluid pressure might be potentially due to a lithostatic-hydrostatic transition of pressure-attending fluid loss during UST formation. Highly fluctuating lithostatic-hydrostatic pressures created by fluid exsolution allowed shifting of the stability field from a quartz-feldspar cotectic to a single-phase quartz. The compositions of brine fluid assemblages hosted in the quartz phenocrysts deviated from the fluids trapped in the UST quartz, especially regarding the Rb/Sr and Fe/Mn ratios and W and Mo concentrations. The study of melt and fluid inclusions in the Eonyang UST sample showed that the exsolution of magmatic fluid was highly periodic. A single pulse of magmatic fluids of variable salinities/densities might have created a single UST sequence, and a new batch of magmatic fluid exsolution would be required to create the next UST sequence.

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Growth and textural evolution during crystallization of quartz and feldspar in hydrous, rhyolitic melt

Cited by 8 publications

References 40 publications

Deciphering Clues Regarding Magma Composition Encoded in Quartz‐Hosted Embayments and Melt Inclusions Through Direct Numerical Simulations

Deciphering Clues Regarding Magma Composition Encoded in Quartz‐Hosted Embayments and Melt Inclusions Through Direct Numerical Simulations

Nucleation delay in water-saturated rhyolite during decompression in shallow volcanic systems and its implications for ascent dynamics

Periodically Released Magmatic Fluids Create a Texture of Unidirectional Solidification (UST) in Ore-Forming Granite: A Fluid and Melt Inclusion Study of W-Mo Forming Sannae-Eonyang Granite, Korea

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