Selected X-ray crystallographic data, molar volumes, and densities of minerals and related substances

Robie, Richard A.; Bethke, Philip M.; Beardsley, Keith M.

doi:10.3133/ofr66113

Cited by 59 publications

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“…Standard state thermodynamic data for quartz, Al 2 Si0 5 polymorphs and corundum were taken directly from Helgeson et al (1978), also the heat capacities of other minerals. Molar volumes were taken from Robie et al (1967). Enthalpies and entropies of almandine, hercynite, Fe-cordierite, staurolite and chloritoid were adjusted to make the data consistent with experimental reversals of the following equilibria: (Ganguly, 1972;Rao & Johannes, 1979;Holdaway & Lee, 1977;Richardson, 1968).…”

Section: Thermodynamic Calculations-methods (I) Equilibria In the Mgomentioning

confidence: 99%

Reaction Textures and Metamorphic Evolution of Sapphirine-bearing Granulites from the Gruf Complex, Italian Central Alps

Droop

Bucher-Nurminen

1984

Journal of Petrology

149

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Mineral chemistries and textures are described from a suite of sapphirine-bearing granulites from the Gruf Complex of the Italian Central Alps. The granulites contain combinations of garnet, orthopyroxene, sapphirine, sillimanite, cordierite, biotite, quartz, spinel, corundum, staurolite, plagioclase, K-feldspar, ilmenite and rutile, in assemblages with low (usually negative) variance. They are outstanding in that they preserve a textural and chemical record of a protracted metamorphic evolution.Reaction textures are common and include: (i) pseudomorphs (e.g. of sillimanite after kyanite); (ii) relatively coarse-grained monomineralic reaction rims (e.g. of cordierite between sapphirine and quartz); (iii) fine-grained symplectitic coronas (e.g. of orthopyroxene + sapphirine round garnet); (iv) inclusions, in garnet cores, of minerals (e.g. staurolite) not found elsewhere in the rocks.Detailed microprobe study has revealed large chemical variations within each phase. Different textural types of each phase have different compositions, and strong zoning is preserved in garnet (Mg/(Mg + Fe) from 0-30 to 0-61) and coarse sapphirine. Inclusion populations in garnet correlate with host composition.The textural and chemical features are interpreted in terms of successive equilibrium assemblages and reactions. Metamorphic conditions operative at each stage in the evolution are calculated using published geothermometers and geobarometers as well as thermodynamically calibrated MAS and FASH equilibria. The results are used to construct a P-T-time path for the sapphirine-granulites, which can be summarized as follows:(i) Increasing Tat high P (>7 kb). Partial melting.(ii) A maximum 7"of -830 °C attained at -10 kb.(iii) Almost isothermal decompression, reaching 750 °Cat -5 kb, under conditions of low /i H ,o-(iv) Further cooling, and decompression. Localized hydration. Rocks exposed. The P-T-time path is interpreted as the product of a single metamorphic cycle (the tertiary 'Lepontine' event) and is extrapolated to the Gruf Complex as a whole. When combined with published geochronological data, the results indicate an average uplift rate in excess of 2 mm/yr for the Gruf Complex between 38 and 30 Ma ago.An in situ partial melting origin for the sapphirine-granulites is favoured. Extraction of an iron-rich granitic liquid from a normal pelitic palaeosome could generate a refractory residue with the required Mg, Al-rich composition. The change in bulk solid composition during partial melting is thought to account for the extraordinarily strong zoning in the garnets.

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Section: Thermodynamic Calculations-methods (I) Equilibria In the Mgomentioning

confidence: 99%

Reaction Textures and Metamorphic Evolution of Sapphirine-bearing Granulites from the Gruf Complex, Italian Central Alps

Droop

Bucher-Nurminen

1984

Journal of Petrology

149

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“…As most data are reported with two sigma uncertainties (Robie et al, 1967(Robie et al, ,1979, these uncertainties can be used to bracket a measured value, using upper and lower 'bounds' provided with most LIP/MAP software packages. These bounds ensure that solutions will be within the uncertainties of these data, and 'best' values can be derived in final optimization of the problem discussed below.…”

Section: Calorimetric Constraintsmentioning

confidence: 99%

“…30-3), and because estimation of mineral expansivities and compressibilities would introduce an additional and unnecessary source of uncertainty in the calculations, we have assumed that molar volumes of minerals (with the exception of quartz, discussed below) are independent of pressure and temperature. Robie et al (1967) CODATA (1978) CODATA (1978) * All values computed using heat capacity functions of Berman & Brown (1985). t Values not used in final optimization for reasons discussed in text.…”

Section: Calorimetric and Volumetric Datamentioning

confidence: 99%

Derivation of Internally-Consistent Thermodynamic Data by the Technique of Mathematical Programming: a Review with Application the System MgO-SiO2-H2O

Berman

Engi²,

Greenwood

et al. 1986

Journal of Petrology

110

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The problem of deriving an optimal set of thermodynamic properties of minerals from a diverse experimental data base is reviewed and a preferred methodology proposed. Mathematical programming(MAP) methods extend the linear programming (LIP) approach first presented by Gordon (1973), and make it possible to account for the type of information conveyed, and the uncertainties attending both phase equilibrium data and direct measurements of phase properties. For phase equilibrium data which are (in most cases) characterized by non-normal error distributions across experimental brackets, the midpoint of a bracket is no more probable than other points, and the data are best treated by considering the inequality in the change in Gibbs free energy of reaction at each half-bracket. Direct measurements of phase properties can be assumed to have approximately normal error distributions, and the MAP technique optimizes agreement with these values by using the principles of least squares in the definition of an objective function. The structure of this problem, treatment of uncertainties in various types of experimental data, and method of optimizing final solutions are discussed in some detail.The method is applied to experimental data in the MgO-SiO 2 -H 2 O system, where inconsistencies among the data are resolved and an optimal set of thermodynamic properties is presented. The derived standard state entropies and volumes agree with all direct measurements (within their uncertainties), as do enthalpies of formation from the elements except for those of talc (+16 kJ mol" •), anthophyllite (+ 14 kJ mol~'), and brucite (-1 kJ mol~'). Stable phase relations in the system have the topology predicted by Greenwood (1963Greenwood ( , 1971, with quartz-and forsterite-absent invariant points at 683 "C-6-4 kb and 797 °C-12 kb respectively, repeating at 552 °C-120 b and 550 °C-55 b. The thermodynamic analysis indicates little remaining flexibility in the phase relations, which, when combined with suitable activity models for solid solution, should allow for accurate determination of the conditions of metamorphism of ultramafic rocks.

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“…%): Or 29.1, Pl (Ab+ An) 36.8, Robie et al (1967), whole-rock density of the Říčany granite from Hejtman (1948). Original data are in bold.…”

Section: Chemical Methodsmentioning

confidence: 99%

Distribution of elements among minerals of a single (muscovite-) biotite granite sample – an optimal approach and general implications

Janoušek¹,

Navrátil²,

Trubač³

et al. 2014

Geologica Carpathica

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Abstract:The petrography and mineral chemistry of the coarse-grained, weakly porphyritic (muscovite-) biotite Říčany granite (Variscan Central Bohemian Plutonic Complex, Bohemian Massif) were studied in order to assess the distribution of major and trace elements among its minerals, with consequences for granite petrogenesis and availability of geochemical species during supergene processes. It is demonstrated that chemistry-based approaches are the best suited for modal analyses of granites, especially methods taking into account compositions of whole-rock samples as well as their mineral constituents, such as constrained least-squares algorithm. They smooth out any local variations (mineral zoning, presence of phenocrysts, schlieren…) and are robust in respect to the presence of phenocrysts or fabrics. The study confirms the notion that the accessory phases play a key role in incorporation of many elements during crystallization of granitic magmas. Especially the REE seem of little value in petrogenetic modelling, unless the role of accessories is properly assessed and saturation models for apatite, zircon, monazite±rutile carefully considered. At the same time, the presence of several P-, Zr-and LREE-bearing phases may have some important consequences for saturation thermometry of apatite, zircon and monazite.

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Selected X-ray crystallographic data, molar volumes, and densities of minerals and related substances

Cited by 59 publications

References 0 publications

Reaction Textures and Metamorphic Evolution of Sapphirine-bearing Granulites from the Gruf Complex, Italian Central Alps

Reaction Textures and Metamorphic Evolution of Sapphirine-bearing Granulites from the Gruf Complex, Italian Central Alps

Derivation of Internally-Consistent Thermodynamic Data by the Technique of Mathematical Programming: a Review with Application the System MgO-SiO2-H2O

Distribution of elements among minerals of a single (muscovite-) biotite granite sample – an optimal approach and general implications

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