Macdonald, R., Sumita, M., Schmincke, H.-U., Bagiński, B., White, J.C., and Ilnicki, S.S., 2015, Peralkaline felsic magmatism at the Nemrut volcano, Turkey: Impact of volcanism on the evolution of Lake Van (Anatolia). IV. Contributions to Mineralogy and Petrology, v. 169, article 34, 22 p. (doi: 10.1007/s00410-015-1127-6)
Nemrut volcano, adjacent to Lake Van (Turkey), is one of the most important peralkaline silicic centres in the world, where magmatism for ~570,000 years has been dominated by peralkaline trachytes and rhyolites. Using onshore and Lake Van drill site tephra samples, we document the phenocryst and glass matrix compositions, confirming a complete spectrum from very rare mafic to dominantly silicic magmas. Magma mixing has been common and, along with the multi-lineage nature of the magmas, indicates that Nemrut has been a very open system where, nevertheless, compositionally zoned caps developed during periods of relative eruptive quiescence. Geothermometry suggests that the intermediate-silicic magmas evolved in an upper crustal magma reservoir at temperatures between 1100 and 750 °C, at fO2 close to the FMQ buffer. The silicic magmas either were halogen poor or exsolved a halogen-rich phase prior to or during eruption. An unusual Pb-rich phase, with up to 98.78 wt% PbO, is interpreted as having exsolved from the intermediate-rhyolitic magmas.
Contributions to Mineralogy and Petrology