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High-pressure, High-temperature Deformation Experiment Using the New Generation Griggs-type Apparatus
Published on: April 3, 2018
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Deep crustal deformation driven by reaction-induced weakening.
Mathieu Soret1,2, Jacques Précigout3, Holger Stünitz3,4
1Institut des Sciences de la Terre d'Orléans (ISTO), UMR 7327, Université d'Orléans, CNRS/BRGM, Orléans, 45071, France. math.soret@gmail.com.
Nature Communications
|July 11, 2025
Summary
Deep crustal shear zones localize strain via dissolution-precipitation creep, not just dislocation creep. Transient fluid flow, driven by chemical changes, accelerates this process, impacting plate tectonics.
Area of Science:
- Geology
- Tectonics
- Geophysics
Background:
- Deep crustal shear zones are crucial for plate tectonics but their evolution is not fully understood.
- Conventional models focus on dislocation creep in monomineralic aggregates, which is challenged by strong mineral properties at high pressures and temperatures.
Purpose of the Study:
- To investigate strain localization mechanisms in deep crustal shear zones under eclogite-facies conditions.
- To elucidate the role of fluid flow and chemo-mechanical processes in shear zone development.
Main Methods:
- Deformation experiments conducted at eclogite-facies conditions.
- Analysis of strain localization and mass transfer mechanisms.
Main Results:
- Strain is efficiently localized by dissolution-precipitation creep at lower stresses than dislocation creep.
- Transient fluid flow, triggered by grain boundary movements and reactions, episodically accelerates strain accommodation and mass transfer.
- Thermo-hydro-mechanical-chemical processes are interconnected and drive shear zone development.
Conclusions:
- Dissolution-precipitation creep is a key mechanism for strain localization in deep crustal shear zones, irrespective of mineral strength.
- Rheological changes driven by transient fluid flow, linked to chemical disequilibrium in subducting materials, control the initiation and evolution of subduction plate interfaces beyond the seismogenic zone.
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