Igneous thermometers and barometers based on plagioclase + liquid equilibria: Tests of some existing models and new calibrations
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Keith D. Putirka
Abstract
Although many formulations of plagioclase + liquid equilibria have been calibrated in the last decade, few models specifically address the issue of temperature (T) prediction. Moreover, for those that do, T error is not addressed, greatly limiting their use as geothermometers. Several recent models of plagioclase-liquid equilibria are thus tested for their ability to recover T from their calibration data, and predict T from experiments not used for calibration. The models of Sugawara (2001) and Ghiorso et al. (1995, 2002) outperform earlier calibrations. These models perform reasonably well at T > 1100 °C, though recovery and prediction of T is less precise for hydrous compositions. In addition, these models cannot be integrated with geo-hygrometers, or other mineral-melt thermometers and barometers; the following expression predicts T with up to 40% greater precision:
Because these thermometers are pressure (P) sensitive, a temperature-sensitive barometer was also developed:
In these models, T is in Kelvins and P is in kbar. Anpl and Abpl are the fractions of anorthite and albite in plagioclase, calculated as cation fractions: An = CaO/(CaO + NaO0.5 + KO0.5) and Ab = NaO0.5/ (CaO+NaO0.5+KO0.5). Terms such as Alliq refer to the anhydrous cation fraction of Al in the liquid; H2O in Equation 1 is in units of wt%. Errors on these models are comparable to those for clinopyroxene thermobarometers: In Equation 1, R = 0.99 and the standard error of estimate (SEE) is 23 K; for Equation 2, R = 0.94 and the SEE is 1.8 kbar. The models successfully recover mean pressures for experimental data that are not used for calibration, and are furthermore able to recover near-1-atm P estimates for volcanic rocks from Kilauea, Hawaii, which are thought to have crystallized at or very near Earth's surface.
© 2015 by Walter de Gruyter Berlin/Boston
Articles in the same Issue
- Comparative planetary mineralogy: Valence state partitioning of Cr, Fe, Ti, and V among crystallographic sites in olivine, pyroxene, and spinel from planetary basalts
- The origin of orthopyroxene/biotite + plagioclase coronas from the Bolangir anorthosite complex (India), and implications for reconstructing P-T paths
- Dellaventuraite, NaNa2(MgMn23+Ti4+Li)Si8O22O2, a new anhydrous amphibole from the Kajlidongri Manganese Mine, Jhabua District, Madhya Pradesh, India
- Successive zoning of Al and H in hydrothermal vein quartz
- The Ti-saturation surface for low-to-medium pressure metapelitic biotites: Implications for geothermometry and Ti-substitution mechanisms
- Thermochemistry of hydrotalcite-like phases in the MgO-Al2O3-CO2-H2O system: A determination of enthalpy, entropy, and free energy
- Igneous thermometers and barometers based on plagioclase + liquid equilibria: Tests of some existing models and new calibrations
- Thermodynamic properties of the Tschermak solid solution in Fe-chlorite: Application to natural examples and possible role of oxidation
- Experimental data on the Tschermak substitution in Fe-chlorite
- Nanometer-sized, divalent-Mn, hydrous silicate domains in geothermal brine precipitates
- Geometric crystal chemical models for structural analysis of micas and their stacking polytypes
- Fundamental difference between synthetic powder and natural or synthetic single-crystal 1M micas: Geometric homo-octahedral vs. geometric meso-octahedral sheets
- The crystal structures of synthetic Fe2(SO4)3(H2O)5 and the type specimen of lausenite
- Experimental study of plagioclase rim growth around anorthite seed crystals in rhyodacitic melt
- Luminescence study of defects in synthetic as-grown and HPHT diamonds compared to natural diamonds
- Molar absorptivities of OH and H2O in rhyolitic glass at room temperature and at 400600 °C
- Ordering and elasticity associated with low-temperature phase transitions in lawsonite
- Formation of metastable cubic-perovskite in high-pressure phase transformation of Ca(Mg, Fe, Al)Si2O6
- Oxygen isotope heterogeneities and diffusion profile in composite metamorphic-magmatic garnets from the Pyrenees
- Unmixed spinel in chromitite from the Iwanai-dake peridotite complex, Hokkaido, Japan: A reaction between peridotite and highly oxidized magma in the mantle wedge
- Mn-bearing “oxy-rossmanite” with tetrahedrally coordinated Al and B from Austria: Structure, chemistry, and infrared and optical spectroscopic study
- Geochemical applications of the simple salt approximation to the lattice energies of complex materials
- Letter: A method for controlling alkali-metal oxide activities in one-atmosphere experiments and its application to measuring the relative activity coeficients of NaO0.5 in silicate melts
- Letter: Very low solubility of rutile in H2O at high pressure and temperature, and its implications for Ti mobility in subduction zones
- Letter: Microscopic strain in synthetic pyrope-grossular solid solutions determined by synchrotron X-ray powder diffraction at 5 K: The relationship to enthalpy of mixing behavior
- Letter: Ferrous hydroxy carbonate is a stable transformation product of biogenic magnetite
Articles in the same Issue
- Comparative planetary mineralogy: Valence state partitioning of Cr, Fe, Ti, and V among crystallographic sites in olivine, pyroxene, and spinel from planetary basalts
- The origin of orthopyroxene/biotite + plagioclase coronas from the Bolangir anorthosite complex (India), and implications for reconstructing P-T paths
- Dellaventuraite, NaNa2(MgMn23+Ti4+Li)Si8O22O2, a new anhydrous amphibole from the Kajlidongri Manganese Mine, Jhabua District, Madhya Pradesh, India
- Successive zoning of Al and H in hydrothermal vein quartz
- The Ti-saturation surface for low-to-medium pressure metapelitic biotites: Implications for geothermometry and Ti-substitution mechanisms
- Thermochemistry of hydrotalcite-like phases in the MgO-Al2O3-CO2-H2O system: A determination of enthalpy, entropy, and free energy
- Igneous thermometers and barometers based on plagioclase + liquid equilibria: Tests of some existing models and new calibrations
- Thermodynamic properties of the Tschermak solid solution in Fe-chlorite: Application to natural examples and possible role of oxidation
- Experimental data on the Tschermak substitution in Fe-chlorite
- Nanometer-sized, divalent-Mn, hydrous silicate domains in geothermal brine precipitates
- Geometric crystal chemical models for structural analysis of micas and their stacking polytypes
- Fundamental difference between synthetic powder and natural or synthetic single-crystal 1M micas: Geometric homo-octahedral vs. geometric meso-octahedral sheets
- The crystal structures of synthetic Fe2(SO4)3(H2O)5 and the type specimen of lausenite
- Experimental study of plagioclase rim growth around anorthite seed crystals in rhyodacitic melt
- Luminescence study of defects in synthetic as-grown and HPHT diamonds compared to natural diamonds
- Molar absorptivities of OH and H2O in rhyolitic glass at room temperature and at 400600 °C
- Ordering and elasticity associated with low-temperature phase transitions in lawsonite
- Formation of metastable cubic-perovskite in high-pressure phase transformation of Ca(Mg, Fe, Al)Si2O6
- Oxygen isotope heterogeneities and diffusion profile in composite metamorphic-magmatic garnets from the Pyrenees
- Unmixed spinel in chromitite from the Iwanai-dake peridotite complex, Hokkaido, Japan: A reaction between peridotite and highly oxidized magma in the mantle wedge
- Mn-bearing “oxy-rossmanite” with tetrahedrally coordinated Al and B from Austria: Structure, chemistry, and infrared and optical spectroscopic study
- Geochemical applications of the simple salt approximation to the lattice energies of complex materials
- Letter: A method for controlling alkali-metal oxide activities in one-atmosphere experiments and its application to measuring the relative activity coeficients of NaO0.5 in silicate melts
- Letter: Very low solubility of rutile in H2O at high pressure and temperature, and its implications for Ti mobility in subduction zones
- Letter: Microscopic strain in synthetic pyrope-grossular solid solutions determined by synchrotron X-ray powder diffraction at 5 K: The relationship to enthalpy of mixing behavior
- Letter: Ferrous hydroxy carbonate is a stable transformation product of biogenic magnetite
