Work

Large volume torsion (LVT) apparatuses for rock deformation at high pressure and temperature

Year: 2025

Type: article

Abstract: Laboratory studies of rock rheology rely on purpose-built devices that can apply planetarily relevant pressures, temperatures, and non-hydrostatic stresses. Generating these pressures and stresses requires the application of large forces over small specimen areas. However, because rocks are generally polymineralic and deformation microstructures form across many length scales, it is advantageous to study relatively large (millimetric) specimens. In addition, many microstructures continue to evolve with progressive strain, so it is vital that some apparatus are able to generate enough shear strain to study these deformation phenomena. This contribution describes two new rock deformation apparatus-the Large Volume Torsion apparatus-at Washington University in St. Louis, which are capable of deforming geological specimens at high pressure and temperature (P = 3 GPa; T = 1800 K). Deformation is imposed in a torsional geometry, which enables the generation of extremely large shear strains (γ > 100) relevant to Earth's plate boundaries and convecting mantle. A large specimen (diameter up to 4.2 mm) permits detailed postmortem microstructural analysis. Apparatus design, calibration, experimental procedures, and some examples of applications are reviewed.

Source: Review of Scientific Instruments

DOI: 10.1063/5.0221218

Authors: Philip Skemer, Hélène Couvy, Andrew J. Cross, Joshua A. H. Littleton, Caroline Bollinger

Institutions: Washington University in St. Louis, Woods Hole Oceanographic Institution, University of Manchester

Language: English

Topic: High-pressure geophysics and materials

Subfield: Geophysics

Field: Earth and Planetary Sciences

Domain: Physical Sciences

Open Access status: green

Funders: National Science Foundation, Washington University in St. Louis, Directorate for Geosciences