The glass transition and the non-Arrhenian viscosity of carbonate melts
- 1 June 2022
- journal article
- research article
- Published by Mineralogical Society of America in American Mineralogist: Journal of Earth and Planetary Materials
- Vol. 107 (6), 1053-1064
- https://doi.org/10.2138/am-2021-7752
Abstract
We report the first calorimetric observation of the glass transition for a carbonate melt. A carbonate glass [55K(2)CO(3)-45MgCO(3) (molar)] was quenched from 780 degrees C at 0.1 GPa. The activation energy of structural relaxation close to the glass transition was derived through a series of thermal treatments comprising excursions across the glass transition at different heating rates. Viscosities just above the glass transition temperature were obtained by applying a shift factor to the calorimetric results. These viscosity measurements (in the range of 10(9) Pa center dot s) at supercooled temperatures (ca. 230 degrees C) dramatically extend the temperature range of data for carbonates, which were previously restricted to superliquidus viscosities well below 1 Pa center dot s. Combining our calorimetrically derived results with published alkaline-earth carbonate melt viscosities at high temperatures yields a highly non-Arrhenian viscosity-temperature relationship and confirms that carbonate liquids are "fragile." Based on simulations, fragile behavior is also exhibited by Na2CO3 melt. In both cases, the fragility presumably relates to the formation of temperature-dependent low-dimensional structures and Vogel-Fulcher-Tammann (VFT) curves adequately describe the viscosity-temperature relationships of carbonate melts below 1000 degrees C.Keywords
This publication has 101 references indexed in Scilit:
- Relationship between topological order and glass forming ability in densely packed enstatite and forsterite composition glassesProceedings of the National Academy of Sciences of the United States of America, 2011
- Vitreous forsterite (Mg2SiO4): Synthesis, structure, and thermochemistryGeophysical Research Letters, 2001
- Structural controls on the solubility of CO2 in silicate melts: Part II: IR characteristics of carbonate groups in silicate glassesChemical Geology, 2001
- Cooling rates of hyaloclastites: applications of relaxation geospeedometry to undersea volcanic depositsBulletin of Volcanology, 2000
- Britte reaction of a high-temperature ion meltEurophysics Letters, 1997
- The equivalence of enthalpy and shear stress relaxation in rhyolitic obsidians and quantification of the liquid-glass transition in volcanic processesJournal of Volcanology and Geothermal Research, 1995
- The equilibrium geometry of carbonate melts in rocks of mantle compositionEarth and Planetary Science Letters, 1989
- Properties of Carbonatite Magma and Processes in Carbonatite Magma ChambersThe Journal of Geology, 1983
- Inadequacies of Viscosity Theories for a Vitreous KNO3-Ca(NO3)2 MeltJournal of the American Ceramic Society, 1971
- Molten Carbonate Electrolytes: Physical Properties, Structure, and Mechanism of Electrical ConductanceJournal of the Electrochemical Society, 1961