FN Archimer Export Format
PT J
TI Viscosity of crystal-free silicate melts from the active submarine volcanic chain of Mayotte
BT 
AF Verdurme, Pauline
   Le Losq, Charles
   Chevrel, Oryaëlle
   Pannefieu, Salomé
   Médard, Etienne
   Berthod, Carole
   Komorowski, Jean-Christophe
   Bachèlery, Patrick
   Neuville, Daniel R.
   Gurioli, Lucia
AS 1:1;2:2;3:1,2,3;4:2;5:1;6:1,2,4;7:2;8:1;9:2;10:1;
FF 1:;2:;3:;4:;5:;6:;7:;8:;9:;10:;
C1 Université Clermont Auvergne, CNRS, IRD, OPGC, Laboratoire Magmas et Volcans, F-63000 Clermont-Ferrand, France
   Université Paris Cité, Institut de physique du globe de Paris, CNRS, F-75005 Paris, France
   Observatoire volcanologique du Piton de la Fournaise, Institut de physique du globe de Paris, 97418 La Plaine des Cafres, France
   Observatoire volcanologique et sismologique de la Guadeloupe, Institut de physique du globe de Paris, 97113 Gourbeyre, France
C2 UNIV CLERMONT AUVERGNE, FRANCE
   UNIV PARIS CITE, FRANCE
   OBSERV VOLCANOLOG PITON FOURNAISE, FRANCE
   OBSERV VOLCANOLOG SISMOLOG GUADELOUPE, FRANCE
IF 3.9
TC 2
UR https://archimer.ifremer.fr/doc/00817/92849/99223.pdf
LA English
DT Article
CR GEOFLAMME
   MAYOBS
   MAYOBS1
   MAYOBS2
   MAYOBS21
   MAYOBS23
   MAYOBS4
   MD 228 / MAYOBS15
BO Pourquoi pas ?
   Marion Dufresne
DE ;Rheology;Alkali magmas;Submarine volcano;Volcanic eruption;Raman spectroscopy
AB Following an unprecedented seismic activity that started in May 2018, a new volcanic edifice, now called Fani Maoré, was constructed on the ocean floor 50 km east of the island of Mayotte (Indian Ocean). This volcano is the latest addition to a volcanic chain characterized by an alkaline basanite-to-phonolite magmatic differentiation trend. Here, we performed viscosity measurements on five silicate melts representative of the East-Mayotte Volcanic Chain compositional trend: two basanites from Fani Maoré, 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. At super-liquidus temperatures, basanites have the lowest viscosity (0.11–0.34 to 0.99–1.16 log10 Pa⸱s), phonolites the highest (1.75–1.91 to 3.10–3.89 log10 Pa⸱s), while the viscosity of the tephriphonolite falls in between (0.89–1.97 log10 Pa⸱s). Near the glass transition, viscosity measurements have only been performed for one phonolite melt because obtaining pure glass samples for the basanite and tephriphonolite compositions was unsuccessful. This was due to the formation of nanolites upon quench as evidenced by Raman spectroscopy. The phonolite viscosity ranges from of 10.19 log10 Pa⸱s at 1058 K to 12.30 log10 Pa⸱s at 986 K. Comparison with existing empirical models revealed an underestimation of 1.2 to 2.0 log units at super-liquidus and undercooled temperatures, respectively, for the phonolite. This 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. The 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 is very fluid, presenting a viscosity around 2.6 log10 Pa⸱s. In contrast, the anhydrous phonolite crystal- and bubble-free melt would have a viscosity around 6–10 log10 Pa⸱s at expected eruptive temperatures, which range from 800 to 1000 °C (1073–1273 K). Considering that both basanite and phonolite lavas from the Mayotte submarine volcanic chain contain <6% crystals and a significant amount of water, such viscosity values are probably upper limits. The new viscosity measurements are essential to define eruptive models and to better understand the storage and transport dynamics of Comoros Archipelago magmas, and of alkaline magmas in general, from the source to the surface. 
PY 2023
PD MAR
SO Chemical Geology
SN 0009-2541
PU Elsevier BV
VL 620
UT 000934106500001
DI 10.1016/j.chemgeo.2023.121326
ID 92849
ER

EF