Oxidation state of iron in mantle-derived magmas of the Icelandic rift zone

摘要: Olivine tholeiites are mantle-derived magmas that formed by partial melting of their deep sources and which have equilibrated with mineral assemblages at slightly different subcrustal pressure-temperature conditions prior to eruption. The minimum depth the pre-eruptive reservoirs these is in order 10–15 km liquidus temperatures fall within range 1180–1240 ‡C. Three types primitive olivine exposed along rift zones Iceland. In present study, ferric/ferrous ratios natural glasses (pillow crusts) three were obtained Mossbauer spectrometry. This technique particularly well suited for analysis high-Mg since it resolves microcrystallites contribute ferrous iron chemical analysis. All results 10–15% Fe(III). At temperature glasses, this ratio corresponds fugacity close fayalite-magnetite-quartz-oxygen (FMQ) buffer an uncertainty less than one log unit fO2. result confirms there no significant difference oxidation state magma types.