An experimental study of amphibole stability in low-pressure granitic magmas and a revised Al-in-hornblende geobarometer

Abstract

This expression recovers equilibration pressures of our calibrant dataset, comprising both new and published experimental and natural data, to within ±16 % relative uncertainty. An uncertainty of 10 % relative for a typical Al tot value of 1.5 apfu translates to an uncertainty in pressure estimate of 0.5 kbar, or 15 % relative. Thus the accuracy of the barometer expression is comparable to the precision with which near-solidus amphibole rim composition can be characterised.

Deposits, petrology and mechanism of the 2010–2013 eruption of Kizimen volcano in Kamchatka, Russia

“…We used the amphibole thermobarometers of Ridolfi et al (2010), Ridolfi and Renzulli (2012) and Mutch et al (2016) to interpret magma storage conditions prior to eruption. Generally, due to the large errors related to the pressure calculation, the applicability of these barometric formulations is under constant critique (Shane and Smith 2013;Erdmann et al 2014).…”

Geo‐fO2: Integrated Software for Analysis of Magmatic Oxygen Fugacity

“…Calibration of this geothermometer was based on compositions of biotite in metamorphic rocks. To check its applicability to igneous rocks, experimental data for magmatic biotites (Andújar et al, 2008;Andújar & Scaillet, 2012;Fabbrizio et al, 2006;Fabbrizio & Carroll, 2008;Mutch et al, 2016;Nandedkar et al, 2014) were used to calculate crystallization temperature using equation (16). Differences between calculated and experimentally measured temperatures were in the range of −26°C to +65°C (see supporting information Table S1).…”

Evaluation of P-T and Ƒo2 Conditions of Crystallization for Monzonitoides of the Velitkenay Granite-Migmatite Massif (Arctic Chukotka) Based on Mineral Thermobaro- And Oxybarometry

“…Плагиоклазы в большинстве случаев однородны по составу и относятся к андезину An [31][32][33][34][35][36][37][38][39] ; согласно петрографическим наблюдениям, относятся к первовыделениям.…”

“…Применение большинства амфиболовых геобарометров основано на степени насыщения амфиболов алюминием. Так, барометр «Аl в амфиболе» [21,28,30,34,38,42,46] контролируется суммарным содержанием алюминия в амфиболе. Амфибол-плагиоклазовый термометр [23,29] основан на количествах катионов Si и Al в тетраэдрической и Al в M 2 позициях структуры амфиболов.…”