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Restudy of pyroxene-pyroxene equilibration temperatures for ordinary chrondrite meteorites
Contributions to Mineralogy and Petrology, 1974Experimental verification of the conclusions of Van Schmus and Koffman (1967) that the equilibration temperatures of ordinary chondrites are roughly the same regardless of classification, and that these temperatures range from 770 to 860 C. The higher average relative equilibrium temperatures found are attributed to improvements in microprobe ...
Bunch, T. E., Olsen, E.
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Geochimica et Cosmochimica Acta, 1973
Phase equilibria determined in high-pressure studies of the systems Mg2Si2O6-CaMgSi2O6 and MgSiO3-Mg3Al2Si3O12 can be used to estimate equilibration conditions of ultramafic rocks containing the assemblage enstatite + diopside + garnet. Garnet lherzolite nodules from kimberlites in northern Lesotho appear to have equilibrated in the upper mantle at ...
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Phase equilibria determined in high-pressure studies of the systems Mg2Si2O6-CaMgSi2O6 and MgSiO3-Mg3Al2Si3O12 can be used to estimate equilibration conditions of ultramafic rocks containing the assemblage enstatite + diopside + garnet. Garnet lherzolite nodules from kimberlites in northern Lesotho appear to have equilibrated in the upper mantle at ...
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The crystal chemistry of pyroxenes and amphiboles, 1. Pyroxenes
Earth-Science Reviews, 1968Abstract Experimental determination of the phase boundaries in relevant systems, and the detailed determination of crystal structures, are together yielding increased understanding of the relationships observed among the naturally occurring pyroxenes.
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Single-pyroxene thermobarometry
Tectonophysics, 1980Abstract Enstatites in peridotites from the Vourinos ophiolites, Greece, have exceptionally high Cr/Al ratios, though the pyroxenes are in equilibrium with picotite. Phase-chemistry data yield new empirical relations for the critical effect of Cr on Al solubility, in full agreement with local Cr/Al ratio variations observed in some massifs. These new
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Lithos, 1968
Meteoritic pyroxenes, while analogous in many respects to those from terrestrial rocks, show some unique features. Among these are the presence of minerals close to MgSiO3 in composition, the common occurence of minerals belonging to the clinoenstatite-clinohypersthene series, the rarity of calcium-rich and aluminium-rich pyroxenes, and the absence of ...
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Meteoritic pyroxenes, while analogous in many respects to those from terrestrial rocks, show some unique features. Among these are the presence of minerals close to MgSiO3 in composition, the common occurence of minerals belonging to the clinoenstatite-clinohypersthene series, the rarity of calcium-rich and aluminium-rich pyroxenes, and the absence of ...
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Intergrowth of pyroxene and pyroxenoid; chain periodicity faults in pyroxene
Physics and Chemistry of Minerals, 1984Intergrowth of clinopyroxenes (augite, A) and pyroxenoids (Fe-rhodonite and pyroxferroite, Pxo) was observed by transmission electron microscopy. The following orientation relationship was found: (001)Pxo is parallel to \((1\mathop {\bar 1}\limits^ + \bar 1)_{\text{A}}\) and \([1\bar 10]_{Pxo}\) is parallel to [011]A. This relationship can be explained
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Elasticity of pyroxene-garnet and pyroxene-ilmenite phase transformations in germanates
Physics of the Earth and Planetary Interiors, 1974Abstract Ultrasonic data for the velocities of the low- and high-pressure polymorphs of germanate compounds undergoing the pyroxene-garnet (CaGeO 3 , CdGeO 3 ) and pyroxene-ilmenite (MgGeO 3 , MnGeO 3 ) phase transformations have been determined as a function of pressure to 7.5 kbar at room temperature for polycrystalline specimens hot-pressed at ...
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1973
Orthopyroxene is one of the few important rock-forming minerals that can be considered as quasi-binary without significant loss of accuracy. Usually more than 95% of the mineral is a crystalline solution of the end members enstatite (MgSiO3) and ferrosilite (FeSiO3). Fe2+ and Mg2+ are distributed between two nonequivalent sites M 1 and M 2.
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Orthopyroxene is one of the few important rock-forming minerals that can be considered as quasi-binary without significant loss of accuracy. Usually more than 95% of the mineral is a crystalline solution of the end members enstatite (MgSiO3) and ferrosilite (FeSiO3). Fe2+ and Mg2+ are distributed between two nonequivalent sites M 1 and M 2.
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