Titre du document / Document title

Rheological properties of basaltic lavas at sub-liquidus temperatures: laboratory and field measurements on lavas from Mount Etna

Auteur(s) / Author(s)

PINKERTON H. ⁽¹⁾ ; NORTON G. ⁽²⁾ ;

Affiliation(s) du ou des auteurs / Author(s) Affiliation(s)

⁽¹⁾ Environmental Science Division, Lancaster University, Lancaster LA1 4YQ, ROYAUME-UNI
⁽²⁾ British Geological Survey, Kingsley Dunham Centre, Keyworth, Nottingham NG12 5GG, ROYAUME-UNI

Résumé / Abstract

Copyright (c) 1996 Elsevier Science B.V. All rights reserved. Models of many magmatic processes require accurate data on the rheological properties of lava at sub−liquidus temperatures. Laboratory measurements of the rheological properties of basalts erupted on Mount Etna in 1983 were made at various crystal concentrations in a specially designed furnace using a Haake Rotovisco viscometer attached to a spindle designed to eliminate slippage at the melt−spindle interface. Measurements were made at strain rates between 0.3 and 5 s⁻¹ over the range of eruption temperatures on Mount Etna (1084−1125°C). At temperatures above 1120°C, the 1983 lava behaves as a Newtonian fluid. At lower temperatures, the lava is a thixotropic, pseudoplastic fluid with a maximum yield strength of 78 Pa at a temperature of 1087°C. In view of its low yield strength over this temperature range, the rheological behaviour of the lava approximates to that of a power law fluid. Apparent viscosities at unit shear strain rates increase from 150 Pa s at 1125°C to 3000 Pa s at 1084°C. Unit strain rate apparent viscosities measured in the field using a rotating vane viscometer range from 1385 Pa s to 1630 Pa s. These values are in close agreement with those measured at the same temperature in the laboratory and with those calculated theoretically from the physico-chemical properties of the lava.

Revue / Journal Title

Journal of volcanology and geothermal research   ISSN 0377-0273   CODEN JVGRDQ 

Source / Source

1995, vol. 68, n^o4, pp. 307-323

Langue / Language

Anglais

Editeur / Publisher

Elsevier, Amsterdam, PAYS-BAS  (1976) (Revue)

Mots-clés anglais / English Keywords

Sicily ; Mount Etna ; basalts ; magmas ; laboratory studies ; in situ ; rheology ; temperature ; liquidus ; lava ; melting ; models ; viscosity ; fluid dynamics ; Italy ; Europe ; volcanic rocks ; igneous rocks ;

Mots-clés français / French Keywords

Sicile ; Volcan Etna ; Basalte ; Magma ; Essai laboratoire ; Essai in situ ; Rhéologie ; Température ; Liquidus ; Lave ; Fusion ; Modèle ; Viscosité ; Dynamique fluide ; Italie ; Europe ; Roche volcanique ; Roche ignée ;

Mots-clés espagnols / Spanish Keywords

Sicilia ; Etna ; Basalto ; Magma ; Ensayo laboratorio ; Ensayo in situ ; Reología ; Temperatura ; Lava ; Fusión ; Modelo ; Viscosidad ; Dinámica fluido ; Italia ; Europa ; Roca volcánica ; Roca ignea ;

Localisation / Location

INIST-CNRS, Cote INIST : 17236,