Mantle oxygen fugacity exerts a primary control on mass exchange between Earth's surface and interior at subduction zones, but the major factors controlling mantle oxygen fugacity (such as volatiles and phase assemblages) and how tectonic cycles drive its secular evolution are still debated. We present integrated measurements of redox-sensitive ratios of oxidized iron to total iron (Fe3+/SigmaF...

[1] The water solubility in pyrope-rich garnet was determined between pressures of 5–9 GPa and temperatures of 1373– 1473 K under silica activity and oxygen fugacity similar to those expected in the Earth’s upper mantle. We found that pyrope-rich garnet has substantial water solubility up to 0.1 wt% under these conditions. In addition, the water content in garnet varied as a function of chemica...

We report the results of an experimental calibration of oxygen isotope fractionation between quartz and zircon. Data were collected from 700 to 1000 C, 10–20 kbar, and in some experiments the oxygen fugacity was buffered at the fayalite–magnetite–quartz equilibrium. Oxygen isotope fractionation shows no clear dependence on oxygen fugacity or pressure. Unexpectedly, some high-temperature data (9...

We estimated the water fugacity (f H2O) in the trachytic magma of Phlegrean Fields using the biotite–magnetite–sanidine equilibrium. We confirm that the partly ionic model is the most appropriate to estimate annite activity (aannite) for the experimental biotite. Crystallization experiments were carried out on a representative sample of trachytic Breccia Museo eruption, Naples, Italy. Experimen...

Written by G. Jeffrey Taylor Hawai'i Institute of Geophysics and Planetology Studies have inferred that the oxidation state of Martian basaltic meteorites (the shergottites) is correlated with diagnostic geochemical parameters. For example, Meenakshi Wadhwa (Field Museum, Chicago) showed that as the ratio of triply-charged europium to doubly-charged europium (Eu3+/Eu2+) increases in a group of ...

The numerical simulation of a level IV fugacity model coupled to a dispersion-advection equation to simulate the environmental concentration of a pesticide in rice fields is presented. The model simulates the dynamic distribution of the pesticide in a compartmental system constituted by air, water, rice plants and bottom sediment together with saturated soil layers. The level IV fugacity model ...

High-pressure oxygen fugacity (‘redox’) sensors are widely used to make estimates of the effective concentration of oxygen in experimental petrology. They typically rely on iron either diffusing into a nominally iron free mineral (e.g. iron into magnesiowüstite [1]) or iron alloying with a noble metal[2, 3]. In both cases the iron content of the sensor material should reflect the prevailing oxy...

Abstract This research article proposes the use of a novel variant of the HS algorithm (harmony search), i.e. SFHS (self-regulated fret width harmony search algorithm), for calculating and predicting fugacity and activity coefficients in binary mixtures. Parameter selection was carried out based on preliminary results with different standard test functions. Different previously reported systems...

In the previous multi-solid models,φ approach is used for the calculation of fugacity in the liquid phase. For the first time, in the proposed multi-solid thermodynamic model,γ approach has been used for calculation of fugacity in the liquid mixture. Therefore, some activity coefficient models have been studied that the results show that the predictive Wilson model is more appropriate than othe...

Recently Beaton, de Gier and Guttmann proved a conjecture of Batchelor and Yung that the critical fugacity of self-avoiding walks interacting with (alternate) sites on the surface of the honeycomb lattice is 1 + √ 2. A key identity used in that proof depends on the existence of a parafermionic observable for self-avoiding walks interacting with a surface on the honeycomb lattice. Despite the ab...