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| Titel |
Stress distribution in samples from solid confining medium deformation experiments: An experimental and numerical study |
| VerfasserIn |
Sebastian Cionoiu, Lucie Tajcmanova, Evangelos Moulas, Holger Stünitz |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250138928
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| Publikation (Nr.) |
 EGU/EGU2017-2069.pdf |
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| Zusammenfassung |
| Shear experiments for the Calcite-Aragonite system were performed in a (Griggs-Type) solid
medium deformation apparatus at 600˚ C. The confining pressure (σ3) was maintained
0.1 – 0.2GPa below the Calcite-Aragonite transition which occurs at 1.47GPa. The first
principal stress (σ1) reached 1.55 – 1.8GPa, depending on the sample strength. Thus the
bulk sample pressure, approximated by P2D = (σ1 + σ3)/2 or P3D = (σ1 + 2*σ3)/3 was
closely varying around the transition pressure.
Raman spectroscopic data show a strong, systematic heterogeneity in the distribution of
the phase transformation in the shear plane (σ1-σ3 plane). Light microscopy reveals
heterogeneous, strain and grain-size distribution. The phase transition is complete at the
center and thinned parts of the experimental shear zone, while regions close to the corners of
the pistons confining the shear and around those show minor transformation. This is
interpreted as being a result of stress, strain and pressure variations within the shear
zone.
To further investigate different mechanisms contributing to the phase transition, the local
distribution of first order parameters as pressure, stress and strain in the experiment must be
understood. To achieve this, numerical modelling based on a finite difference code in Matlab
is used (2D and 3D). The modelling results are then compared to experiments, analyzed in the
σ1-σ3 and the σ1-σ2 plane. |
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