Stability of the assemblage iron-rich orthopyroxene-olivine-quartz

Smith, Douglas C.

doi:10.2475/ajs.271.4.370

Cited by 37 publications

(11 citation statements)

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“…To keep the 1-bar enthalpy difference to within the uncertainty of Navrotksy et al's (1979) data, and additionally the heat of formation of fayalite to within experimental uncertainty, allows destabilizing fayalite by about 828-900 J/mol, which has the effect that the fayalite-ringwoodite boundary is lowered by − 0.23 GPa. Additionally the phase boundary between fayalite + quartz and orthoferrosilite is moved to pressures − 0.28 GPa below our present result, which is twice the difference between the boundaries determined by Bohlen et al (1980) and Smith (1971). Stabilizing quartz or destabilizing orthoferrosilite to keep this boundary at the same location results in the same effect as the first possibility for changing the fayalite-ringwoodite boundary, that the ringwoodite + coesite field becomes stable at temperatures below 1473 K. Our present result represents the boundary of Bohlen et al (1980), which is the lowest in pressure relative to previous measurements and the conclusion is that we can change the fayalite-ringwoodite boundary by only − 0.13 GPa, leaving a difference of 0.25 GPa relative to Ono et al's (2013) data points.…”

Section: Phase Diagramscontrasting

confidence: 57%

Thermophysical properties and phase diagrams in the system MgO–SiO2–FeO at upper mantle and transition zone conditions derived from a multiple-Einstein method

2019

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We applied a lattice vibrational technique, based on representing the vibrational density of states with multiple-Einstein frequencies, to determine consistency of data on thermophysical properties and phase diagrams in the system MgO-FeO-SiO 2. We present analyses of these data in the temperature range between 0 and 2000 K and pressure range between 0 and 20 GPa. The result is a database containing phases relevant to the Earth upper mantle and transition zone. We show that consistency of different datasets associated with the dissociation of the ringwoodite form of Fe 2 SiO 4 depends on the crucible material that has been used to perform partitioning experiments between ringwoodite and ferropericlase, and that this results in different phase diagrams for FeSiO 3 and the post-spinel part of Mg 2 SiO 4-Fe 2 SiO 4. We show that the existence of a phase field coesite + ringwoodite in the phase diagram of FeSiO 3 is possible and that it might be used to fine-tune pressure scales. We demonstrate that the phase boundary between coesite and quartz is very sensitive to the low-temperature heat capacity of coesite and that heat capacity data of β-quartz are too large to be reconciled with the phase boundary between β-quartz and coesite. We compare our results with seismic data associated with the 410 km seismic discontinuity.

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Section: Phase Diagramscontrasting

confidence: 57%

Thermophysical properties and phase diagrams in the system MgO–SiO2–FeO at upper mantle and transition zone conditions derived from a multiple-Einstein method

2019

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“…Other workers [3][4][5] have shown that FeSiO3 is a stable phase at high pressures. More recently Smith [1 ] and Wood and Strens [6] have attempted to experimentally calibrate parts of the Fe2 SiO4-SiO2 and Fe2SiO4-Mg2SiO4-SiO2 systems. Smith [1 ] has determined the pres- and has also experimentally evaluated the effect of MgO on the orthopyroxene-olivine-quartz system at 900°C.…”

Section: Introductionmentioning

confidence: 99%

Reinvestigation and application of olivine-quartz-orthopyroxene barometry

Bohlen

Essene

Boettcher

1980

Earth and Planetary Science Letters

133

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“…6" needs some explanation as well. In experiments SMITH (1971) has shown that at relatively low pressures and temperatures between 600 and 1000 ~ C the reaction orthopyroxene --olivine + quartz proceeds to the right in systems with high Fe/(Fe § ratios. In experiments SMITH (1971) has shown that at relatively low pressures and temperatures between 600 and 1000 ~ C the reaction orthopyroxene --olivine + quartz proceeds to the right in systems with high Fe/(Fe § ratios.…”

Section: Thermometamorphism--m1mentioning

confidence: 99%

Polyphase metamorphic sedimentary xenoliths from Mt. Amiata volcanics (Central Italy); evidence for a partially disrupted contact aureole

Bergen

Manfred²

1983

Geol Rundsch

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Metasediment~ire Einschliisse in den krustal anatektischen Rhyodaziten des vulkanischen Komplexes Monte Amiata lassen sich untergliedern in eine Siliea-arme Gruppe, reich an Alumininm-Mineralien, und eine kleine Silica-reiche Gruppe mit Quarz im t3bermal3. Die beobaehteten Texturen, unterstiitzt vonder Mineralehemie weisen auf drei metamorphe Ereignisse. Die Ilegionalmetamorphose M0 ist h~ufig verbunden mit Deformation, wiihrend zwei nachfolgende progressive Thermometamorphosen M 1 und M2 verursacht worden sind vonder magmatischen Warme. Die Mineralgesellschaften des M 1 sind representativ fiir die Pyroxen-Hornfels Fazies und die Gesellsehaften des M e, in Kombination mit Anweisungen ffir partielle Aufschmelzung und Sanidinisation, suggerieren Umstande der Sanidinit-Fazies. Die Einschliisse werden interpretiert als xenolithisehe Fragmente einer Kontaktaureole, die noehmals metamorphosiert wurden naeh der Aufnahme ins Magma. Die Aureole entstand in ~e-mesozoischen Formationen wiihrend der Akkumulation des Schmelzes in einer Magmakammer. Die geschiitzten Druckbedingungen fiir M 1 sind im Ein!dang mit der M6glichkeit einer ziemlich tiefen Position der W~irmequelle gehSrend z-am Geothermalfeld des Monte Amiata. AbstractMetasedimentary inclusions in the crustal anateetie rhyodacites of Mt. Amiata volcanic complex can be subdivided into a silica-poor group, rich in aluminous minerals, and a small silica-rich group containing abundant quartz. Textural observations, supported by mineral chemistry provide evidence for three metamorphic events. The regional metamorphic M 0 is often associated with deformation, and two subsequent progressive thermometamorphic events, M1 and Me, are caused by the magmatic heat. Mineral assemblages of M 1 are indicative for the pyroxene-hornfels facies, and assemblages of M2, in combination with evidence for partial melting and sanidinization, suggest sanidinite facies conditions. The inclusions are interpreted mainly as xenolithic fragments of a contact aureole, which were remetamorphosed after incorporation by the magma. The aureole formed in pre-mesozoic formations during accumulation of the melt in a magmachamber. Constraints on pressure conditions for M 1 indicate the possibility of a fairly large depth of the heat-source giving rise to Mt. Amiata geothermal field. R6sum6Les enclaves m6tas6dimentaires des rhyodacites anatectiques erustales du complexe voleanique du Monte Amiata se laissent subdiviser en deux groupes: l'un panvre en sfliee avee des min6raux alumineux abondants, et l'autre, moins important, eontenant tm exe6s de quartz. Les textures, support6es par la min6ralogie chimique t4moignent de trois 6v6nements m6tamorphiques. Le m6tamorphism r6gional M0 est souvent assoei6

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Stability of the assemblage iron-rich orthopyroxene-olivine-quartz

Cited by 37 publications

References 0 publications

Thermophysical properties and phase diagrams in the system MgO–SiO2–FeO at upper mantle and transition zone conditions derived from a multiple-Einstein method

Thermophysical properties and phase diagrams in the system MgO–SiO2–FeO at upper mantle and transition zone conditions derived from a multiple-Einstein method

Reinvestigation and application of olivine-quartz-orthopyroxene barometry

Polyphase metamorphic sedimentary xenoliths from Mt. Amiata volcanics (Central Italy); evidence for a partially disrupted contact aureole

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