Chemical control of Al-solubility in orthopyroxene and its implications on pyroxene geothermometry

Lithospheric mantle duplex beneath the central Mojave Desert revealed by xenoliths from Dish Hill, California

“…[37] Equilibrium temperatures in spinel facies peridotites can also be derived from orthopyroxene-spinel Cr-Al exchange equilibria [Sachtleben and Seck, 1981;WittEickschen and Seck, 1991], and, ideally, Cr and Al contents in orthopyroxene are sufficient to obtain equilibrium temperatures (T Cr/Al-opx ) [Witt-Eickschen and Seck, 1991]. Because diffusion rates of Al and Cr in orthopyroxene are much lower than those of Ca in the temperature range of interest (800 -1200°C) [Smith and Barron, 1991;WittEickschen and Seck, 1991;Griffin et al, 1996, and references therein], T Cr/Al-Opx may be the only geothermometer able to track long-term thermal histories recorded by zoned orthopyroxene porphyroclasts.…”

Petrology, Mineral and Isotope Geochemistry of the External Liguride Peridotites (Northern Apennines, Italy)

“…The thermometers of Wood & Banno (1973) and Wells (1977) are based on the exchange of Ca and Mg between clinopyroxene and orthopyroxene. The thermometer of Sachtleben & Seek (1981) is based on the partitioning of Al between orthopyroxene and spinel, and is not applicable to plagioclase-bearing assemblages. Therefore, this method has been only applied to obtain the T equilibration of the spinel-bearing assemblage.…”

Corrigendum

“…The orthopyroxene and clinopyroxene atomic formulae and pyroxene components were independently calculated using the procedures defined by Sturm (2002), which are summarized in the associated Excel ® template (Supplementary Table 10a) includes the temperature estimates for a number of geothermobarometers (Brey and Köhler 1990;Sacthleben and Seck 1981;Wells 1977;WittEickschen and Seck 1991;Wood and Banno 1973) and an f (O 2 ) geobarometer (Balhaus et al, 1991) published by other authors.…”