Storage conditions and eruptive dynamics of central versus flank eruptions in volcanic islands: The case of Tenerife (Canary Islands, Spain)

摘要: Abstract We report the results of phase equilibrium experiments on a phonolite produced during one most voluminous flank eruptions (ca. 1 km3) Teide–Pico Viejo complex (Tenerife Island). Combined with previous experimental and volcanological data we address factors that control structure phonolitic plumbing system stratovolcanoes. The Roques Blancos erupted ca 1800 BP contains ~ 14 wt.% phenocrysts, mainly anorthoclase, biotite, magnetite, diopside lesser amounts ilmenite. Crystallization were performed at temperatures 900 °C, 850 °C 800 °C, in pressure range 200 MPa to 50 MPa. oxygen fugacity (fO2) was varied between NNO + 0.3 (0.3 log units above Ni–NiO solid buffer) NNO-2, whilst dissolved water contents from 7 wt.% 1.5 wt.%. comparison natural proportions compositions, including glass, indicates magma stored prior eruption 900 ± 15 °C, 50 ± 15 MPa, about 2.2 wt.% H2O melt, an NNO-0.5 (± 0.5). difference composition rim cores anorthoclase phenocrysts suggests heated by 50 °C before eruption, upon intrusion hotter tephriphonolitic magma. storage conditions those inferred for other phonolites volcanic shows are fed reservoirs located relatively shallow depths (1–2 km) compared feeding Teide central (5 km).