Petrological imaging of an active pluton beneath Cerro Uturuncu, Bolivia

• Published in: Contributions to mineralogy and petrology 2014-03, Vol.167 (3), p.1, Article 980
• Main Authors: Muir, Duncan D., Blundy, Jon D., Hutchinson, Michael C., Rust, Alison C.
• Format: Article
• Language: English
• Subjects: APVC; Carbon dioxide; Crystal texture; Dacites; Earth and Environmental Science; Earth Science with specialization in Mineral Chemistry, Petrology and Tectonics; Earth Sciences; Geochemistry; Geology; Geothermometry; Geovetenskap med inriktning mot mineralogi, petrologi och tektonik; Magma; Magnetite; Melt inclusions; Mineral Resources; Mineralogy; Original Paper; Petrology; Porphyry; Quartz; Remote sensing; Scientific imaging; Synthetic aperture radar; Temperature measurements; Trace elements; Volcanic eruptions; Volcanoes
• ISSN: 0010-7999; 1432-0967; 1432-0967
• DOI: 10.1007/s00410-014-0980-z

Uturuncu is a dormant volcano in the Altiplano of SW Bolivia. A present day ~70 km diameter interferometric synthetic aperture radar (InSAR) anomaly roughly centred on Uturuncu’s edifice is believed to be a result of magma intrusion into an active crustal pluton. Past activity at the volcano, spanning 0.89 to 0.27 Ma, is exclusively effusive and almost all lavas and domes are dacitic with phenocrysts of plagioclase, orthopyroxene, biotite, ilmenite and Ti-magnetite plus or minus quartz, and microlites of plagioclase and orthopyroxene set in rhyolitic groundmass glass. Plagioclase-hosted melt inclusions (MI) are rhyolitic with major element compositions that are similar to groundmass glasses. H 2 O concentrations plotted versus incompatible elements for individual samples describe a trend typical of near-isobaric, volatile-saturated crystallisation. At 870 °C, the average magma temperature calculated from Fe–Ti oxides, the average H 2 O of 3.2 ± 0.7 wt% and CO 2 typically