Torsion experiments on synthetic magmatic suspensions
type: Dataset
description: The microstructures and the rheological behaviour of synthetic magmatic suspensions in the range of 0% to 80% solid fraction have been investigated in torsion experiments. The liquid phase is a haplogranitic melt (HPG) with 2.5 Wt % H20. The solid phase is composed of a sieved fraction (45Μm<Φ<90Μm) of crushed alumina grains that avoid any chemical interaction with the melt such as dissolution/crystallisation during synthesis of the suspension and during the experiments. Four analogous suspensions with respectively 0, 20, 60 and 80% solid fraction were synthesised at 100 MPa and 950°C during one month ensuring a homogeneous repartition of water in the melt. Torsion experiments were performed in a high-pressure, high temperature Paterson apparatus at 300 MPa confining pressure, temperatures ranging from 475°C to 1000°C and shear strain rates from 2.1x10-3 to 2.0x10-5 s-1. Pure melt was deformed up to Γ=8.8. Steping tests at various shear strain rates yielded a stress exponent of ~1.1 with an apparent viscosity ~1010.9 Pa.s at T=475°C and a stress exponent of ~1.0 with an apparent viscosity ~1010.3 Pa.s at T=500°C. These results confirm the Newtonian character of pure haplogranitic melts at high pressure. The 20% solid fraction suspension departs from Newtonian behaviour with a stress exponent n=1.4 and an apparent log viscosity varying from 11.5 (T=500°C) to 10.6 (T=600°C) both at a strain rate ~2.10-4 s-1. Shape Preferred Orientations (SPO) of alumina grains and shapes and orientations of initially spherical (22 Μm in diameter) residual air bubbles were analysed using the inertia tensor method on polished sections normal to the shear direction. For Γ=2.6 the solid fraction developed a strong SPO with a mean direction Α=2° anticlockwise from the shear direction and bubbles passively deformed with a mean long axis orientation 24° anticlockwise and a mean aspect ratio R=2.07. For Γ=17.5, the SPO of the alumina grains became significantly weaker but still homogeneous in…
landing page: 15th Conference on Deformation Mechanism, Rheology and Tectonics
keyword: conference-papers
keyword: infoeu-reposemanticsconferenceobject
keyword: sdemcgcgenvironmental-sciencesglobal-changesdomainsdemcgcg
keyword: sdustuvosciences-of-the-universe-physicsearth-sciencesvolcanology
issued: 2026-05-07T22:04:57.682024
modified: 2026-05-07T22:04:57.682029
language: en
contact point: Organization
  fn: CCSD

test_moissonnage_selune
type: Agent

Torsion experiments on synthetic magmatic suspensions
type: Distribution
format: HTML
access URL: https://insu.hal.science/hal-00091533
issued: 2026-05-07T22:04:57.687554
modified: 2026-05-07T22:04:57.654655