Results 231 to 240 of about 5,319 (257)

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
T. H. Hansteen, A. Klugel
openaire   +1 more source

Orthopyroxene thermobarometry in simple and complex systems

Contributions to Mineralogy and Petrology, 1987
In the system FeO-MgO-Al2O3-SiO2 (FMAS), the equilibrium Al-content of orthopyroxene coexisting with olivine and spinel was reversed in 18 experiments at 1 340° C and 11 or 18 kbar, using graphite capsules and PbO flux. In the CFMAS system (+CaO), the Al-contents of ortho- and clinopyroxene coexisting with olivine and spinel were reversed in 5 ...
openaire   +1 more source

WinAmptb: A Windows program for calcic amphibole thermobarometry

Periodico di Mineralogia, 2017
WinAmtb is a Microsoft ® Visual Basic software developed for electron microprobe calcic amphibole analyses to calculate the pressure ( P ), temperature ( T ) and oxygen fugacity ( f O 2 ) conditions of amphibole-bearing alkaline to calc-alkaline rocks. The program estimates the structural formulae of calcic group amphibole analyses on the basis of IMA-
Yavuz, Fuat, Döner, Zeynep
openaire   +1 more source

Thermobarometry Gone Astray

2009
Quantitative thermobarometers require selection of a univariant reaction, consideration of dilutions in all phases and application to fully buffered systems. Empirical thermobarometers include AlIV in chlorite, Al in hornblende, Ti in biotite, phengite barometry and various clay and organic transformations.
openaire   +1 more source

THERMOBAROMETRY OF XENOLITHS FROM DEEP-SEATED ROCKS

International Geology Review, 1993
A system of two-pyroxene thermometry is proposed, based on the distribution coefficients of one and three components between coexisting orthopyroxenes and clinopyroxenes and the position of the orthopyroxene isotherm-isobars in the ternary system MgSiO3-CaSiO3-FeSiO3.
openaire   +1 more source

High‐precision relative thermobarometry: theory and a worked example

Journal of Metamorphic Geology, 2000
A number of sources of uncertainty are involved in thermobarometric calculations, the most important of which are associated with analytical precision, activity–composition (a–x) relationships, and thermodynamic data. Statistical treatment of these uncertainties results in relatively large uncertainties on the calculated values of pressure and ...
null Worley, null Powell
openaire   +1 more source

Clinopyroxene in postshield Haleakala ankaramite: 1. Efficacy of thermobarometry

Contributions to Mineralogy and Petrology, 2015
Magma storage depth is a fundamental aspect of a volcano’s magmatic plumbing system that may be resolved using mineral-melt thermobarometry, assuming crystal growth occurs at near-equilibrium conditions. We acquire major and minor element compositional analyses of whole rock, groundmass separates, and clinopyroxene in ankaramite erupted ca.
Julia Hammer, Samantha Jacob, Benoit Welsch, Eric Hellebrand, John Sinton   +4 more
openaire   +1 more source

GEOTHERMS OF CONTINENTAL LITHOSPHERE BASED ON XENOLITH THERMOBAROMETRY

International Geology Review, 1993
The thermobarometry of garnet lherzolite and pyroxenite xeno-liths from kimberlitic explosion pipes and volcanoes has been used to determine the geotherms, values of the surface heat flow, and the thickness of the lithosphere in regions of Archean orogeny (the Kaapvaal Craton, South Africa and Lesotho, and the Siberian Platform in the vicinity of the ...
openaire   +1 more source

The Granulite Uncertainty Principle: Limitations on Thermobarometry in Granulites

The Journal of Geology, 1989
There are three geothermometers based on reversed experimental data and applicable to granulites: the two-pyroxene, two-oxide, and garnet-clinopyroxene thermometers. All have apparent closure temperatures below those of the granulite facies. This casts significant doubt on the concept that "peak" temperatures are routinely obtained from ion-exchange ...
B. Ronald Frost, Thomas Chacko
openaire   +1 more source

The current status of thermobarometry in metamorphic rocks

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