TY - JOUR

T1 - Viscosity of andesitic melts-new experimental data and a revised calculation model

AU - Vetere, Francesco

AU - Behrens, Harald

AU - Holtz, Francois

AU - Neuville, Daniel R.

N1 - Funding Information: This work was supported by the German Science Foundation (DFG, project Be1720-12) and by the German–French cooperation program (PROCOPE D/0205707). We thank H. O'Neill and a second unknown reviewer for helpful comments improving the quality of the paper. [SG] Copyright: Copyright 2011 Elsevier B.V., All rights reserved.

PY - 2006/4/28

Y1 - 2006/4/28

N2 - The viscosity of a synthetic andesite-like melt was measured in the low viscosity range (101-106 Pa s) using the falling sphere(s) method and in the high viscosity range (108-1013 Pa s) using parallel-plate viscometry. Falling sphere experiments with melts containing 2.3 and 5.6 wt.% H2O were carried out in an internally heated gas pressure vessel (IHPV) at 500 MPa confining pressure. The sinking velocity of Pt and Pd spheres and in one case of a corundum sphere was used to measure the melt viscosity. In addition, a creep experiment was performed at ambient pressure using a glass containing 2.73 wt.% H2O . A more water-rich glass (5.6 wt.% H2O ) was investigated with a high pressure parallel-plate viscometer at 400 MPa confining pressure in an IPHV. By combining our new data with previous results for a similar melt composition we derived the following expression to describe the viscosity η (in Pa s) as a function of temperature T (in K) and water content w (in wt.%){A formula is presented}. This expression reproduces the experimental data (191 in total) in the viscosity range from 101 to 1013 Pa s with a root mean squared deviation of 0.15 log units.

AB - The viscosity of a synthetic andesite-like melt was measured in the low viscosity range (101-106 Pa s) using the falling sphere(s) method and in the high viscosity range (108-1013 Pa s) using parallel-plate viscometry. Falling sphere experiments with melts containing 2.3 and 5.6 wt.% H2O were carried out in an internally heated gas pressure vessel (IHPV) at 500 MPa confining pressure. The sinking velocity of Pt and Pd spheres and in one case of a corundum sphere was used to measure the melt viscosity. In addition, a creep experiment was performed at ambient pressure using a glass containing 2.73 wt.% H2O . A more water-rich glass (5.6 wt.% H2O ) was investigated with a high pressure parallel-plate viscometer at 400 MPa confining pressure in an IPHV. By combining our new data with previous results for a similar melt composition we derived the following expression to describe the viscosity η (in Pa s) as a function of temperature T (in K) and water content w (in wt.%){A formula is presented}. This expression reproduces the experimental data (191 in total) in the viscosity range from 101 to 1013 Pa s with a root mean squared deviation of 0.15 log units.

KW - Andesite

KW - Falling sphere

KW - HO

KW - Unzen Volcano

KW - Viscosity

UR - http://www.scopus.com/inward/record.url?scp=33645950795&partnerID=8YFLogxK

U2 - 10.1016/j.chemgeo.2005.10.009

DO - 10.1016/j.chemgeo.2005.10.009

M3 - Article

AN - SCOPUS:33645950795

VL - 228

SP - 233

EP - 245

JO - Chemical Geology

JF - Chemical Geology

SN - 0009-2541

IS - 4

ER -