Synthetic gedrite: a stable phase in the system MgO-Al2O3-SiO2-H2O (MASH) at 800 degrees C and 10 kbar water pressure, and in the influence of FeNaCa impurities
Article Abstract:
Research was conducted to determine gedrite stability in the MgO-Al2O3-SiO2-H2O (MASH) system, both with and without impurities. The MASH system was prepared from the purest chemicals available at 10 kbar water pressure and 800 degrees C. Results reveal that pure gedrite free of iron, sodium and calcium may possibly have only a small PT stability field in the MASH system. The use of a second starting material with FeNaCa impurities showed that the true stability field of such slightly impure gedrites may be larger than that of the pure MASH phase and extend at least to 15 kbar, 800 degrees C.
Publication Name: Contributions to Mineralogy and Petrology
Subject: Earth sciences
ISSN: 0010-7999
Year: 1999
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Electron optical and X-ray powder diffraction study of synthetic and natural potassic cordierites
Article Abstract:
The tweed-pattern in submicroscopic K-bearing Mg-cordierites could be used to determine the thermal processes that happened during the development of the rocks. Microstructural and X-ray diffraction experiments were performed on several buchite and paralava Mg-cordierites. The structural effects caused by different levels of K-content intrusions were taken into consideration. The results indicated that the distortion indices derived from microstructural heterogeneity could serve as bases in measuring the extent of thermal influence in the cordierite-bearing samples.
Publication Name: Contributions to Mineralogy and Petrology
Subject: Earth sciences
ISSN: 0010-7999
Year: 1992
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Zn-rich hogbomite formed from gahnite in the metabauxites of the Menderes Massif, SW Turkey
Article Abstract:
A geochemical analysis of the Zn-rich hogbomite of the Menderes Massif in Southwest Turkey was conducted in order study on the mechanisms of formation of this rare mineral. The Zn-rich hogbomite was suggested to have formed as a result of a prograde metamorphic reaction between gahnite from low-grade, regionally metamorphosed diasporites and corundum-bearing metabauxites. The role of a hydrous fluid as a transport mechanism for zinc and aluminum from gahnite was suggested.
Publication Name: Contributions to Mineralogy and Petrology
Subject: Earth sciences
ISSN: 0010-7999
Year: 1993
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- Abstracts: An experimental study of glaucophanic amphiboles in the system Na2O-MgO-Al2O3-SiO2-SiF4 (NMASF): some implications for glaucophane stability in natural and synthetic systems at high temperatures and pressures
- Abstracts: Amphibole composition in tonalite as a function of pressure: an experimental calibration of the Al-in-hornblende barometer
- Abstracts: The low-pressure stability of phase A, Mg7Si2O8(OH)6. Thermal expansivities and compressibilities of hydrous phases in the system MgO-SiO2-H2O: talc, phase A and 10-angstrom phase
- Abstracts: Geochemical evolution of Jurassic diorites from the Bristol Lake region, California, USA, and the role of assimilation
- Abstracts: The system O-S-Fe at 1 bar. Geochemistry of Tertiary tholeiites and picrites from Qeqertarssuaq (Disko Island) and Nuussuaq, West Greenland with implications for the mineral potential of comagmatic intrusions