@article{fdi:010088395,
  title = {{V}iscosity of crystal-free silicate melts from the active submarine volcanic chain of {M}ayotte},
  author = {{V}erdurme, {P}. and {L}e {L}osq, {C}. and {C}hevrel, {M}agdalena {O}ryaelle and {P}annefieu, {S}. and {M}{\'e}dard, {E}. and {B}erthod, {C}. and {K}omorowski, {J}.{C}. and {B}ach{\`e}lery, {P}. and {N}euville, {D}.{R}. and {G}urioli, {L}.},
  editor = {},
  language = {{ENG}},
  abstract = {{F}ollowing an unprecedented seismic activity that started in {M}ay 2018, a new volcanic edifice, now called {F}ani {M}aor{\'e}, was constructed on the ocean floor 50 km east of the island of {M}ayotte ({I}ndian {O}cean). {T}his volcano is the latest addition to a volcanic chain characterized by an alkaline basanite-to-phonolite magmatic differentiation trend. {H}ere, we performed viscosity measurements on five silicate melts representative of the {E}ast-{M}ayotte {V}olcanic {C}hain compositional trend: two basanites from {F}ani {M}aor{\'e}, one tephriphonolite and two phonolites from different parts of the volcanic chain. {A} concentric cylinder viscometer was employed at super-liquidus conditions between 1500 {K} and 1855 {K} and a creep apparatus was used for measuring the viscosity of the undercooled melts close to the glass transition temperature in the air. {A}t super-liquidus temperatures, basanites have the lowest viscosity (0.11-0.34 to 0.99-1.16 log10 {P}a-s), phonolites the highest (1.75-1.91 to 3.10-3.89 log10  {P}a-s), while the viscosity of the tephriphonolite falls in between (0.89-1.97 log10 {P}a-s). {N}ear the glass transition, viscosity measurements were performed for one phonolite melt because obtaining pure glass samples for the basanite and tephriphonolite compositions was unsuccessful.  {T}his is due to the formation of nanolites upon quench as evidenced by {R}aman spectroscopy. {T}he phonolite viscosity ranges from of 10.19 log10 {P}a-s at 1058 {K} to 12.30 log10 {P}a-s at 986 {K}. {C}omparison with existing empirical models reveals an underestimation of 1.2 to 2.0 log units at  super-liquidus and undercooled temperatures, respectively, for the phonolite. {T}his emphasizes (i) the lack of data falling along the alkaline basanite-to-phonolite magmatic differentiation trend to calibrate empirical models, and (ii) the complexity of modeling viscosity variations as  a function of temperature and chemical composition for alkaline compositions. {T}he new measurements indicate that, at eruptive temperatures between 1050 °{C} and 1150 °{C} (1323-1423 {K}), the oxidized, anhydrous, crystal-free and bubble-free basanite melt have a viscosity around 2.6 log10 {P}a-s. {I}n contrast, the anhydrous phonolite crystal- and bubble-free melt would have a viscosity around 6-10 log10 {P}a-s at expected eruptive temperatures, from 800 to 1000 °{C} (1073-1273 {K}). {C}onsidering that both basanite and phonolite lavas from the {M}ayotte submarine volcanic chain contain <6% crystals and a significant amount of water (1-2.3 wt% and 0.8-1.2 wt%, respectively), such viscosity values are probably upper limits. {T}he new viscosity measurements are essential to define eruptive models and to better understand the storage and transport




dynamics of {C}omoros {A}rchipelago magmas, and of alkaline magmas in general, from the source to the surface.},
  keywords = {{MAYOTTE}},
  booktitle = {},
  journal = {{C}hemical {G}eology},
  volume = {620},
  numero = {},
  pages = {121326 [14 ]},
  ISSN = {0009-2541},
  year = {2023},
  DOI = {10.1016/j.chemgeo.2023.121326},
  URL = {https://www.documentation.ird.fr/hor/fdi:010088395},
}