Results 241 to 250 of about 6,691 (288)

New experimental constraints for the evolution and thermobarometry of alkali ultrabasic to intermediate igneous rocks

Journal of Petrology, 2023
We report new experimental data from ultrabasic basanite and ultrabasic tephrite as starting material compositions in the 1350 - 1000°C temperature range.
A. Salazar-Naranjo, S. Vlach
semanticscholar   +1 more source

Fe3+ distribution and Fe3+/𝚺Fe-oxygen fugacity variations in kimberlite-borne eclogite xenoliths, with comments on clinopyroxene-garnet oxy-thermobarometry

Journal of Petrology, 2022
The valence state of iron in mantle-derived melts, such as mid-ocean ridge basalt, is a useful proxy for oxygen fugacity (ƒO2). On subduction, oceanic crust undergoes metamorphic reactions that alter its initial ƒO2, generating compositional and redox ...
S. Aulbach, A. Woodland, V. Stagno, A. Korsakov, D. Mikhailenko, A. Golovin   +5 more
semanticscholar   +1 more source

Multi-thermobarometry and microstructures reveal ultra-high temperature metamorphism in the Grenvillian Oaxacan Complex, Southern Mexico

Soviet Economy, 2022
The Oaxacan Complex represents the largest outcrop of the Mesoproterozoic microcontinent Oaxaquia. It experienced a major tectonometamorphic event, locally known as Zapotecan Orogeny (ca.
A. Ramírez‐Salazar, María del Mar Almazán-López, V. Colás, F. Ortega-Gutiérrez   +3 more
semanticscholar   +1 more source

Thermobarometry in granulites: pitfalls and new approaches

Precambrian Research, 1992
Abstract Computer models of cooling granulite-facies rocks with the assemblage garnet+biotite+sillimanite+K-feldspar±plagioclase+quartz are presented that incorporate simultaneous reaction (net transfer and exchange) and multicomponent diffusion in garnet.
Frank P. Florence, Frank S. Spear
openaire   +2 more sources

On thermobarometry

Journal of Metamorphic Geology, 2008
AbstractThermobarometry, the estimation of the pressure–temperature (P–T) conditions of metamorphism, can be undertaken by using pseudosection calculations as well as by conventional methods. Conventional thermobarometry uses only the equilibrium thermodynamics of balanced reactions between end‐members of minerals, combined with the observed ...
R. POWELL, T. J. B. HOLLAND
openaire   +1 more source

Fluid Inclusion Thermobarometry as a Tracer for Magmatic Processes

Reviews in Mineralogy and Geochemistry, 2008
Fluid inclusions in minerals may form in any type of volcanic or plutonic rock ranging from mafic to silicic compositions. Because all igneous rocks reach fluid saturation at some stage during their evolution, fluids trapped as inclusions in magmatic minerals belong to a certain paragenesis or phase assemblage, which may include minerals, melts and one
Thor H. Hansteen, Andreas Klügel
openaire   +2 more sources

The current status of thermobarometry in metamorphic rocks [PDF]

Geological Society, London, Special Publications, 1989
SummaryInformation on pressure (P) and temperature (T) is a fundamental aspect of research on metamorphic terrains. Unfortunately, many workers employ thermobarometers that are not experimentally calibrated, are insensitive or too sensitive toP-Tchanges, depend on a priori assumptions of water pressure (such as most petrogenetic grids), or are rapidly ...
openaire   +1 more source

Single-pyroxene thermobarometry

Tectonophysics, 1980
Abstract 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
openaire   +2 more sources

Thermodynamic Modeling and Thermobarometry of Metasomatized Rocks

2012
Determining the P-T conditions at which metasomatism occurs provides insight into the physical conditions at which fluid-rock interaction occurs in the crust. However, application of thermodynamic modeling to metasomatized rocks is not without pitfalls.
Didier Marquer, Philippe Goncalves, Emilien Oliot, Emilien Oliot, Cyril Durand   +4 more
openaire   +4 more sources

Status of thermobarometry in granitic batholiths

Earth and Environmental Science Transactions of the Royal Society of Edinburgh, 1996
ABSTRACT:Most granitic batholiths contain plutons which are composed of low-variance mineral assemblages amenable to quantification of the P– conditions that characterise emplacement. Some mineral thermometers, such as those based on two feldspars or two Fe–Ti oxides, commonly undergo subsolidus re-equilibration.
openaire   +2 more sources