A thermodynamic analysis of the system LiAlSiO4-NaAlSiO4-Al2O3-SiO2-H2O based on new heat capacity, thermal expansion, and compressibility data for selected phases

Faßhauer, Detlef W.; Chatterjee, Niranjan D.; Cemič, Ladislav

doi:10.1007/s004100050446

Cited by 25 publications

(39 citation statements)

References 29 publications

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“…The common occurrence of zabuyelite in spodumene-hosted inclusions from many different pegmatites indicates that the zabuyelite-generating process is common to many Li-rich rare-element pegmatites and is probably a consequence of the exsolution of a magmatic volatile phase during the late stages of pegmatite crystallization and its reaction with early spodumene. Data on fluid inclusions in spodumene from the Tanco pegmatite are often cited as evidence for extreme boron enrichment in granitic melts (e.g., Dingwell et al 1996, Fasshauer et al 1998. The results presented here, however, show that the fluid entrapped in spodumenehosted inclusions is not a boron-rich melt.…”

Section: Implications For the Evolution Of Fluid Phases Associated Wicontrasting

confidence: 53%

THE OCCURRENCE AND ORIGIN OF ZABUYELITE (Li2CO3) IN SPODUMENE-HOSTED FLUID INCLUSIONS: IMPLICATIONS FOR THE INTERNAL EVOLUTION OF RARE-ELEMENT GRANITIC PEGMATITES

Anderson

Clark

Gray

2001

The Canadian Mineralogist

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Solid -liquid -vapor fluid inclusions in spodumene in rare-element granitic pegmatites commonly contain one or more highbirefringence minerals. Optical examination and laser Raman spectroscopic analyses of over 500 crystal-rich fluid inclusions in spodumene from Bikita and Kamativi, Zimbabwe, and Bernic Lake (Tanco), Manitoba, indicate that the high-birefringence phase is zabuyelite (Li 2 CO 3 ). Laser Raman spectra were also obtained from fluid inclusions in a wafer of spodumene from the Tanco pegmatite reported to contain the type samples of diomignite (Li 2 B 4 O 7 ). In every fluid inclusion, the high-birefringence phase was shown to be zabuyelite; no phase yielding the Raman spectrum of Li 2 B 4 O 7 was observed. Petrographic analysis indicates that the inclusions are secondary in origin and are trapped within healed fractures and cleavage planes. Essentially all fluid inclusions exhibit extensive necking after the crystallization of solid phases. The dominant solid phases are quartz and zabuyelite. Other minerals such as cookeite, calcite, a cesium-rich phase, apatite and several unidentified minerals were found in fewer than 5% of the fluid inclusions examined. An estimate of the bulk composition of the fluid entrapped within spodumene at Tanco was obtained by averaging the contents of several hundred coeval fluid inclusions, and the composition of individual fluid inclusions was determined using laser Raman spectroscopy, synchrotron X-ray fluorescence and laser ablation -inductively coupled plasma -mass spectrometry. The results indicate that the inclusions in spodumene, like those in the quartz component of SQUI, entrapped a low-salinity (ca. 7 wt.% NaCl equiv.), alkali-rich, aqueous carbonic fluid. We propose that the solid -liquid -vapor inclusions in spodumene from Tanco, Bikita and Kamativi are the products of a reaction between the low-density aqueous carbonic fluid and the host spodumene during the late stages of pegmatite evolution; therefore, they do not represent the products of a complex borosilicate melt as suggested previously.

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Section: Implications For the Evolution Of Fluid Phases Associated Wicontrasting

confidence: 53%

THE OCCURRENCE AND ORIGIN OF ZABUYELITE (Li2CO3) IN SPODUMENE-HOSTED FLUID INCLUSIONS: IMPLICATIONS FOR THE INTERNAL EVOLUTION OF RARE-ELEMENT GRANITIC PEGMATITES

Anderson

Clark

Gray

2001

The Canadian Mineralogist

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“…values reported with these constants, in particular those for the β-phase, as these are perhaps larger than ideal-this is a consequence of the limited number of available data points to which the EOS functions are fitted. Nonetheless, these constants are notably more accurate and appropriate than those reported by Fasshauer et al (1998). These authors evaluated the elastic constants for petalite from synchrotron data, yet they did not account for the occurrence of the pressure induced phase transitions and a b "cycled" the pressure on the sample, thus forcing the crystalline sample to pass through these transitions multiple times.…”

Section: Elastic Constantsmentioning

confidence: 90%

“…It should be noted, however, that a non-conventional metric unit cell has been chosen to ensure that the structural features align with the unit-cell axes. Although there are several reported studies of the relative thermodynamic stability and phase equilibria of the NaAlSiO 4 -LiAlSiO 4 -SiO 2 -H 2 O system (Fasshauer et al 1998;London 1984;Haussühl et al 2012), of which petalite is a key member, there is a lack of accurate high-pressure structural and elasticity data for petalite. The objective of this study was to rectify this situation, and herein we report an extensive HP-XRD analysis of petalite and describe in detail a previously undiscovered high-pressure phase of this mineral (β-phase).…”

Section: Introductionmentioning

confidence: 98%

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Petalite under pressure: Elastic behavior and phase stability

Ross

Zhao

Slebodnick

et al. 2015

American Mineralogist

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The lithium aluminosilicate mineral petalite (LiAlSi 4 O 10 ) has been studied with high-pressure single-crystal X-ray diffraction (HP-XRD) up to 5 GPa. Petalite undergoes two fully reversible pressure-induced first-order phase transitions, not previously reported in the literature, at ca. 1.5 and 2.5 GPa. The first of these transforms the low-pressure α-phase of petalite (P2/c) to an intermediate β′-phase that then fully converts to the high-pressure β-phase at ca. 2.5 GPa. The α → β transition is isomorphic and is associated with tripling of the unit-cell volume. Analysis of the HP-XRD data show that although the fundamental features of the petalite structure are retained through this transition, there are subtle alterations in the internal structure of the silicate double-layers in the β-phase relative to the α-phase. Measurement of the unit-cell parameters of petalite as a function of pressure, and fitting of the data with third-order Birch-Murnaghan equation of state, has provided revised elastic constants for petalite. The bulk moduli of the α-and β-phases are 49(1) and 35(3) GPa, respectively. These values indicate that the compressibility of the α-phase of petalite lies between those of the alkali feldpsars and alkali feldspathoids, whereas the β-phase has a compressibility more comparable with layered silicates. Structure analysis has shown that the compression of the α-phase is facilitated by the rigid body movement of the Si 2 O 7 units from which the silicate double-layers are constructed.

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“…The experimental analysis establishes that the a axial direction is more compressible than the b and c axial directions in the low-pressure range ͑13. 2,[9][10][11][12] Thus, information about high temperature and high pressure ͑HTHP͒ behavior of diaspore appears to be of useful and relevant. The diaspore isothermal bulk modulus K T values are 137.6 GPa, 124.8 GPa, and 141.3 GPa, respectively, at 300 K, at 1900 K, and again at 300 K after quenching.…”

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confidence: 99%

Diaspore crystal structure and compressibility at high pressures and high temperature

Snoussi

et al. 2010

Applied Physics Letters

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We have determined the unit-cell parameters of diaspore α-AlO(OH) at high pressures (13.5–27.8 GPa) and at high temperature (1900 K). Experimental data are compared with the theoretically predicted crystal structure variations derived from density functional theory (DFT) calculations. The experimental analysis establishes that the a axial direction is more compressible than the b and c axial directions in the low-pressure range (13.5–18 GPa) and at 1900 K, whereas all three directions show similar behaviors in the high-pressure range (18–27.8 GPa). The diaspore isothermal bulk modulus KT values are 137.6 GPa, 124.8 GPa, and 141.3 GPa, respectively, at 300 K, at 1900 K, and again at 300 K after quenching. By comparison, the diaspore isothermal bulk modulus KT computed at 300 K and at ambient pressure in the framework of the plane-wave pseudopotential approach is equal to 129.3 GPa.

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A thermodynamic analysis of the system LiAlSiO4-NaAlSiO4-Al2O3-SiO2-H2O based on new heat capacity, thermal expansion, and compressibility data for selected phases

Cited by 25 publications

References 29 publications

THE OCCURRENCE AND ORIGIN OF ZABUYELITE (Li2CO3) IN SPODUMENE-HOSTED FLUID INCLUSIONS: IMPLICATIONS FOR THE INTERNAL EVOLUTION OF RARE-ELEMENT GRANITIC PEGMATITES

THE OCCURRENCE AND ORIGIN OF ZABUYELITE (Li2CO3) IN SPODUMENE-HOSTED FLUID INCLUSIONS: IMPLICATIONS FOR THE INTERNAL EVOLUTION OF RARE-ELEMENT GRANITIC PEGMATITES

Petalite under pressure: Elastic behavior and phase stability

Diaspore crystal structure and compressibility at high pressures and high temperature

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