Partition coefficients for iron between plagioclase and basalt as a function of oxygen fugacity: Implications for Archean and lunar anorthosites

Petrogenesis and geochemistry of the Late Carboniferous rear-arc (or back-arc) pillow basaltic lava in the Bogda Mountains, Chinese North Tianshan

“…8C). Previous studies suggested that high FeO content in plagioclase might be related to high oxygen fugacity (Aigner-Torres et al, 2007;Longhi et al, 1976;Phinney, 1992;Sato, 1989). The high oxygen fugacity inferred for the Bogda basalts contrasts with the relatively low f O2 of the Tarim large igneous provinces (Wei et al, 2014(Wei et al, , 2015.…”

Boundary layer fractionation constrained by differential information from the Kutsugata lava flow, Rishiri volcano, Japan

“…FeO* content in the An-rich plagioclase varies from 0.25 to 0.35 wt% in the North lava, which is independent of the An content, and this was inferred to have reflected the variation of ferric-ferrous ratio in the interstitial melt of the mushy boundary layer ]. However, its variation in the North lava magma is explained by a difference of at most 1 log unit of oxygen fugacity [after Phinney, 1992 Figure B1). A crystallinity of 25 vol% is adopted as the limit for the main magma below the roof mush zone, because the fractionated melt may mix easily with a magma containing <25 vol% crystals [e.g., Marsh, 1996].…”

Arc Crust-Magma Interaction in the Andean Southern Volcanic Zone from Thermobarometry, Mineral Composition, Radiogenic Isotope and Rare Earth Element Systematics of the Azufre-Planchon-Peteroa Volcanic Complex, Chile

“…Although the overall negative correlation between An mol% and Fe concentration for plagioclase in PT-15 is observed, within transects of these phenocrysts sharp increases in An mol% are accompanied by increases in Fe concentrations. The partitioning of Fe into plagioclase is sensitive to oxygen fugacity because of the increase in partition coefficients with increasing fO 2 Ginibre et al, 2002;Phinney, 1992;Sugawara, 2001;Huebner et al, 1989;Wilke and Behrens, 1999 (Van Kooten and Busek, 1978). The rim of phenocryst PT-3A-OL3 shows a quick change in composition (Fo 70 to Fo 54 ) in less than 40µm, indicating that after the long period of stable magmatic conditions with homogeneous growth there was abrupt crystallization and cooling reflecting a change in pressure of magmatic regime (Pearce, 1984;Costa and Dungan, 2005;Costa and Chakraborty, 2004).…”