Hydrothermal alteration of seafloor peridotites does not influence oxygen fugacity recorded by spinel oxybarometry

Revisiting the electron microprobe method of spinel-olivine-orthopyroxene oxybarometry applied to spinel peridotites

Natural peridotite samples containing olivine, orthopyroxene, and spinel can be used to assess the oxygen fugacity ( fO2) of the upper mantle. The calculation requires accurate and precise quantification of spinel Fe3+/SFe ratios. Wood and Virgo (1989) presented a correction procedure for electron microprobe (EPMA) measurements of spinel Fe3+/SFe ratios that relies on a reported correlation bet...

Hydrothermal sediment alteration at a seafloor vent field: Grimsey Graben, Tjörnes Fracture Zone, north of Iceland

[1] An active seafloor hydrothermal system subjects the background sediments of the Grimsey Graben (Tjörnes Fracture Zone) to alteration that produces dissolution of the primary volcaniclastic matrix and replacement/precipitation of sulfides, sulfates, oxides, oxyhydroxides, carbonates and phyllosilicates. Three types of hydrothermal alteration of the sediment are defined on the basis of the do...

Using Vanadium in Spinel as a Sensor of Oxygen Fugacity in Meteorites: Applications to Mars, Vesta, and Other Asteroids

Introduction: Igneous and metamorphic rocks commonly contain a mineral assemblage that allows oxygen fugacity to be calculated or constrained such as FeTi oxides, olivine-opx-spinel, or some other oxybarometer [1]. Some rocks, however, contain a limited mineral assemblage and do not provide constraints on fO2 using mineral equilibria. Good examples of the latter are orthopyroxenites or dunites,...

Pregnancy does not cause structural bioprosthesis alteration.

Moderate dose of watercress and red radish does not reduce oxygen consumption during graded exhaustive exercise

Objective: Very recent studies have reported positive effects of dietary nitrate on the oxygen consumption during exercise. This research aimed to study the effect of moderate dose of high-nitrate vegetables, watercress (Nasturtium officinale) and red radish (Raphanus sativus) compared with a control group on the incremental treadmill exercise test following a standard Bruce protocol controlled...