@article{fdi:010071354,
  title = {{S}tructure of the plumbing system at {T}ungurahua volcano, {E}cuador : insights from phase equilibrium experiments on july-august 2006 eruption products},
  author = {{A}ndujar, {J}. and {M}artel, {C}. and {P}ichavant, {M}. and {S}amaniego, {P}ablo and {S}caillet, {B}. and {M}olina, {I}.},
  editor = {},
  language = {{ENG}},
  abstract = {{U}nderstanding the plumbing system structure below volcanoes and the storage conditions (temperature, pressure, volatile content and oxygen fugacity) of erupted magmas is of paramount importance for eruption forecasting and understanding of the factors controlling eruptive dynamics. {P}hase equilibria experiments have been performed on a {T}ungurahua andesite ({E}cuador) to shed light on the magmatic conditions that led to the {J}uly-{A}ugust 2006 eruptions and the parameters that controlled the eruptive dynamics. {C}rystallization experiments were performed on a representative {A}ugust 2006 mafic andesite product between 950 and 1025{A} degrees {C}, at 100, 200 and 400 {MP}a and {NNO} + 1 and {NNO} + 2 (where {NNO} is nickel-nickel oxide buffer), and water mole fractions in the fluid ({XH}2{O}) from 0 center dot 3 to 1 (water-saturation). {C}omparison of the natural phenocryst assemblage, proportions and phenocryst compositions with our experimental data indicates that the natural andesite experienced two levels of ponding prior to the eruption. {D}uring the first step, the magma was stored at 400 {MP}a (15-16 km), 1000{A} degrees {C}, and contained c. 6 wt % dissolved {H}2{O}. {I}n the second step, the magma rose to a confining pressure of 200 {MP}a (8-10 km), where subsequent cooling (to 975{A} degrees {C}) and water-degassing of the magma led to the crystallization of reversely zoned rims on pre-existing phenocrysts. {T}he combination of these processes induced oxidation of the system and overpressure of the reservoir, triggering the {J}uly 2006 eruption. {T}he injection of a new, hot, volatile-rich andesitic magma from 15-16 km into the 200 {MP}a reservoir shortly before the eruption was responsible for the {A}ugust 2006 explosive event. {O}ur results highlight the complexity of the {T}ungurahua plumbing system in which different magmatic reservoirs can coexist and interact in time and are the main controlling factors of the eruptive dynamics.},
  keywords = {basaltic andesite ; phase equilibrium ; {T}ungurahua ; plumbing system ; pre-eruptive conditions ; experimental petrology ; adakite ; magnesian ; andesite ; {EQUATEUR} ; {TUNGURAHUA} {VOLCAN}},
  booktitle = {},
  journal = {{J}ournal of {P}etrology},
  volume = {58},
  numero = {7},
  pages = {1249--1278},
  ISSN = {0022-3530},
  year = {2017},
  DOI = {10.1093/petrology/egx054},
  URL = {https://www.documentation.ird.fr/hor/fdi:010071354},
}