Coordination change of Ge4+ and Ga3+ in silicate melt with pressure

Mare, Eleanor Rose; O’Neill, Hugh St. C.; Berry, Andrew J.; Frigo, Corinne; Glover, Christopher

doi:10.1016/j.gca.2021.03.008

“…Only zircon free areas of melt > 100 μm were analysed to avoid the possibility of secondary Zr fluorescence. The water contents of the hydrous silicate melts were estimated from the difference between the total oxide concentrations and 100 wt % following the method of Devine et al (1995), which as shown by Mare et al (2021) gives results that agree well with those determined directly by Fourier Transform Infrared (FTIR) spectroscopy. For samples where the major oxide composition of the glass was determined by both WDS and EDS, the results agree within 7% (Supplementary Table ST2).…”

Section: Major Oxide Compositionmentioning

confidence: 91%

A new model for zircon saturation in silicate melts

Crisp

¹

,

Berry

²

2022

Contrib Mineral Petrol

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A new model describing zircon saturation in silicate melts is presented that combines the results of 196 data from new experiments with data from previous experimental studies. In the new experiments, the concentration of Zr in melts coexisting with zircon was determined at temperatures between 800 and 1500 °C for 21 compositions (with alumina saturation index, ASI, from 0.20 to 1.15), containing ~ 1 to 16 wt % FeOT and, for a subset of these conditions, at variable pressure (0.0001 to 4.0 GPa) and water content (0 to 15 wt %). The collated dataset contains 626 data, with 430 from 26 literature studies, and covers conditions from 750 to 1620 °C, (including 45 new data and 106 literature data for temperatures < 1000 °C), ASI 0.20 to 2.00, 0.0001 to 4.0 GPa and 0 to 17 wt % H2O. A limitation of previous models of zircon saturation is the choice of parameter used to describe the silicate melt, which may not be appropriate for all compositions and can result in differences in predicted temperatures of over 200 °C for granitic systems. Here we use optical basicity (Λ), which can be easily calculated from the major oxide components of a melt, to parameterise the composition. Using a non-linear least-squares multiple regression, the new zircon saturation model is:$$\log{\mathrm{Zr}} = 0.96(5) - 5790(95)/T - 1.28(8)P + 12.39(35){\varLambda} + 0.83(9)x.\text{H}{_2}\text{O} + 2.06(16)P{\varLambda} $$ log Zr = 0.96 ( 5 ) - 5790 ( 95 ) / T - 1.28 ( 8 ) P + 12.39 ( 35 ) Λ + 0.83 ( 9 ) x . H 2 O + 2.06 ( 16 ) P Λ where Zr is in ppm, T is temperature in K, P is pressure in GPa, Λ is the optical basicity of the melt, x.H2O is the mole fraction of water in the melt, and the errors are 1σ. This model confirms that temperature and melt composition are the dominant controls on zircon solubility. In addition, pressure and melt water content exert small but resolvable effects on the solubility and are included, for the first time, in a model. Using this new calibration, 92% of the predicted temperatures are within 10% of the experimental temperatures for the collated dataset (with an average temperature difference of 57 °C), while predicted temperatures for only 78 and 62% of the collated dataset are within 10% of the experimental temperature (with average temperature differences > 80 °C) using the widely cited Watson and Harrison (Earth Planet Sci Lett 64:295–304, 1983) and Boehnke et al. (Chem Geol 351:324–334, 2013) models, respectively. This new model can be extrapolated to temperatures below those included in the calibration with greater accuracy and when applied to melt inclusions from the Bishop Tuff, gives temperatures that are in excellent agreement with independent estimates.

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“…The average difference between the water contents determined for the standards and the published values was 0.11 wt.%. Low intensity peaks at 1410 and 1501 cm −1 observed in some of the spectra were assigned to vibrations of CO 3 2− in the glasses 48 and used to determine the concentration of CO 2 49 . The H 2 O and CO 2 contents of the glasses are given in Table S1.…”

Section: Methodsmentioning

confidence: 99%

Fractional crystallisation of eclogite during the birth of a Hawaiian Volcano

Miller

¹

,

O’Neill

²

,

Berry

³

et al. 2022

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The initial melts erupted by a Hawaiian volcano have a range of alkalic compositions but are rarely observed as they are covered by enormous volumes of shield stage tholeiites. A remarkable record of the early evolution of Hawaiian volcanoes, however, is preserved by a volcanic sandstone dredged from the submarine flank of Kilauea, which contains a suite of petrogenetically related pre-shield basanite to nephelinite glasses. Here we show that the systematic variation in the rare earth element (REE) patterns of these samples requires the fractional crystallisation of garnet. A fractionating assemblage of Ca-rich garnet (32%), omphacitic clinopyroxene (63%), and minor phlogopite can explain the variation in the major and trace element contents of the suite. The results suggest fractional crystallisation of eclogite from a primitive Hawaiian melt near the base of the lithosphere (>90 km) and that a deep magma chamber is the first stage in the development of a Hawaiian volcano.

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“…The Ge K-edge XANES has a strong whiteline (WL) feature (1s → 4p) 51 that appears at ∼11110 eV indicating Ge in both sol−gel and hydrothermally synthesized MGO has an oxidation state of +4. 52,53 The WL of MGO:Mn-sg is higher and broader than that of MGO:Mn-h, as shown in Figure 3e, indicating that there are more unoccupied electrons in the Ge 4p level, as the WL intensity is strongly related to the electronic density of the unoccupied state in the conduction band. The Ge K-edge EXAFS spectra in the R space with the first-shell fit are plotted in Figure 3f (the k space plots can be found in Support Information, Figure S8).…”

Section: Resultsmentioning

confidence: 96%

Multiband MgGeO₃-Based Persistent Luminescent Nanophosphors for Dynamic and Multimodal Anticounterfeiting

Liu,

Sun,

Jiang

et al. 2024

ACS Appl. Nano Mater.

0

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Persistent luminescence (PersL) materials are excellent candidates in the dynamic and multimodal anticounterfeiting field. Compared to commercially available micrometer-sized PersL phosphors, nanosized PersL materials could blend more easily with solvents and allow printing patterns with fine details. MgGeO 3 is one of the frequently employed lattice hosts for PersL phosphors. It can accommodate divalent ions such as Mn 2+ to produce deep-red PersL. To date, the only reported method of synthesizing nanosized Mn-doped MgGeO 3 (MGO:Mn) is the sol−gel method. The synthesis product has a wide particle size distribution and suffers severe aggregation. In this work, MGO:Mn nanorods are synthesized, for the first time, with a uniformly distributed morphology. These nanorods exhibit more intense and longer-lasting PersL. A detailed comparative study between the MGO:Mn nanorods developed in this work and the MGO:Mn particles prepared by the sol−gel method is performed to identify the origin of the improved PersL property. We also demonstrate that the afterglow duration of the MGO:Mn nanorods can be further modulated by adding co-dopants such as Yb 3+ , Eu 3+ , and Li + . The Yb 3+ dopant also introduces a second PersL emission band in the near-infrared region of ∼1000 nm. Using a combination of these MGO-based PersL nanorods, dynamic and multimodal anticounterfeiting can be achieved.

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Coordination change of Ge4+ and Ga3+ in silicate melt with pressure

Cited by 12 publications

References 145 publications

A new model for zircon saturation in silicate melts

A new model for zircon saturation in silicate melts

Fractional crystallisation of eclogite during the birth of a Hawaiian Volcano

Multiband MgGeO₃-Based Persistent Luminescent Nanophosphors for Dynamic and Multimodal Anticounterfeiting

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Coordination change of Ge4+ and Ga3+ in silicate melt with pressure

Cited by 12 publications

References 145 publications

A new model for zircon saturation in silicate melts

A new model for zircon saturation in silicate melts

Fractional crystallisation of eclogite during the birth of a Hawaiian Volcano

Multiband MgGeO3-Based Persistent Luminescent Nanophosphors for Dynamic and Multimodal Anticounterfeiting

Contact Info

Product

Resources

About

Multiband MgGeO₃-Based Persistent Luminescent Nanophosphors for Dynamic and Multimodal Anticounterfeiting