Constraining kinetics of metastable olivine in the Marianas slab from seismic observations and dynamic models
Transformation kinetics associated with the presence of a metastable olivine wedge in old and fast subducting slabs has been the subject of many studies in the last years. Even with improvements in kinetics models, many of the parameters are still not well constrained. In particular, there is no con...
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todo:paper_00401951_v526-529_n_p48_Quinteros2023-10-03T14:50:17Z Constraining kinetics of metastable olivine in the Marianas slab from seismic observations and dynamic models Quinteros, J. Sobolev, S.V. Marianas Metastable olivine Numerical modeling Subduction Blocking temperature Force balances Kinetics models Latent heat release Mantle transition zone Marianas Metastable olivine Numerical modeling P waves Positive correlations Seismic observation Shear heating Subducting slabs Subduction Subduction zones Thermal state Thermomechanical model Transformation kinetics Kinetics Latent heat Olivine Seismic waves Viscoelasticity Tectonics coda elastoplasticity isotherm latent heat flux numerical model olivine P-wave parameterization rheology seismic survey slab spinel subduction zone tectonic setting tectonic wedge thermomechanics transition zone viscoplasticity Mariana Trench Pacific Ocean Transformation kinetics associated with the presence of a metastable olivine wedge in old and fast subducting slabs has been the subject of many studies in the last years. Even with improvements in kinetics models, many of the parameters are still not well constrained. In particular, there is no consensus on the blocking temperature that could inhibit the transformation from olivine to spinel. Recently, based on anomalous later phases in the P wave coda and differential P wave slowness, a wedge of metastable olivine was detected in the Marianas subduction zone, that is approximately 25. km wide, at a depth of 590. km and is truncated at 630 km. In this work, a thermomechanical model was used to mimic the subduction in the Marianas and try different blocking temperatures for the olivine/spinel transformation. The model includes, among other features, non-linear elasto-visco-plastic rheology based on laboratory data, phase transformations, latent heat, proper coupling between stress and thermal state of the slab and force balance of the system. The results show a positive correlation between the blocking temperature, depth of the wedge and its distance from the trench (or subduction angle). We compare these results to the situation in the Marianas and suggest that a blocking temperature for the olivine/spinel transformation of approximately 725 °C would be the most likely. The volume of the wedge presents some oscillations that we relate to a runaway effect of the transformation kinetics in the mantle transition zone. Namely, the interaction between latent heat release and the advection of the isotherms due to the subduction velocity. The inclusion of shear heating in the model was fundamental to modeling such a subduction zone. Without shear heating, the slab shows a higher level of internal stress and the necessary bending to mimic the Marianas subduction zone cannot be reached. © 2011 Elsevier B.V. Fil:Quinteros, J. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_00401951_v526-529_n_p48_Quinteros |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
Marianas Metastable olivine Numerical modeling Subduction Blocking temperature Force balances Kinetics models Latent heat release Mantle transition zone Marianas Metastable olivine Numerical modeling P waves Positive correlations Seismic observation Shear heating Subducting slabs Subduction Subduction zones Thermal state Thermomechanical model Transformation kinetics Kinetics Latent heat Olivine Seismic waves Viscoelasticity Tectonics coda elastoplasticity isotherm latent heat flux numerical model olivine P-wave parameterization rheology seismic survey slab spinel subduction zone tectonic setting tectonic wedge thermomechanics transition zone viscoplasticity Mariana Trench Pacific Ocean |
| spellingShingle |
Marianas Metastable olivine Numerical modeling Subduction Blocking temperature Force balances Kinetics models Latent heat release Mantle transition zone Marianas Metastable olivine Numerical modeling P waves Positive correlations Seismic observation Shear heating Subducting slabs Subduction Subduction zones Thermal state Thermomechanical model Transformation kinetics Kinetics Latent heat Olivine Seismic waves Viscoelasticity Tectonics coda elastoplasticity isotherm latent heat flux numerical model olivine P-wave parameterization rheology seismic survey slab spinel subduction zone tectonic setting tectonic wedge thermomechanics transition zone viscoplasticity Mariana Trench Pacific Ocean Quinteros, J. Sobolev, S.V. Constraining kinetics of metastable olivine in the Marianas slab from seismic observations and dynamic models |
| topic_facet |
Marianas Metastable olivine Numerical modeling Subduction Blocking temperature Force balances Kinetics models Latent heat release Mantle transition zone Marianas Metastable olivine Numerical modeling P waves Positive correlations Seismic observation Shear heating Subducting slabs Subduction Subduction zones Thermal state Thermomechanical model Transformation kinetics Kinetics Latent heat Olivine Seismic waves Viscoelasticity Tectonics coda elastoplasticity isotherm latent heat flux numerical model olivine P-wave parameterization rheology seismic survey slab spinel subduction zone tectonic setting tectonic wedge thermomechanics transition zone viscoplasticity Mariana Trench Pacific Ocean |
| description |
Transformation kinetics associated with the presence of a metastable olivine wedge in old and fast subducting slabs has been the subject of many studies in the last years. Even with improvements in kinetics models, many of the parameters are still not well constrained. In particular, there is no consensus on the blocking temperature that could inhibit the transformation from olivine to spinel. Recently, based on anomalous later phases in the P wave coda and differential P wave slowness, a wedge of metastable olivine was detected in the Marianas subduction zone, that is approximately 25. km wide, at a depth of 590. km and is truncated at 630 km. In this work, a thermomechanical model was used to mimic the subduction in the Marianas and try different blocking temperatures for the olivine/spinel transformation. The model includes, among other features, non-linear elasto-visco-plastic rheology based on laboratory data, phase transformations, latent heat, proper coupling between stress and thermal state of the slab and force balance of the system. The results show a positive correlation between the blocking temperature, depth of the wedge and its distance from the trench (or subduction angle). We compare these results to the situation in the Marianas and suggest that a blocking temperature for the olivine/spinel transformation of approximately 725 °C would be the most likely. The volume of the wedge presents some oscillations that we relate to a runaway effect of the transformation kinetics in the mantle transition zone. Namely, the interaction between latent heat release and the advection of the isotherms due to the subduction velocity. The inclusion of shear heating in the model was fundamental to modeling such a subduction zone. Without shear heating, the slab shows a higher level of internal stress and the necessary bending to mimic the Marianas subduction zone cannot be reached. © 2011 Elsevier B.V. |
| format |
JOUR |
| author |
Quinteros, J. Sobolev, S.V. |
| author_facet |
Quinteros, J. Sobolev, S.V. |
| author_sort |
Quinteros, J. |
| title |
Constraining kinetics of metastable olivine in the Marianas slab from seismic observations and dynamic models |
| title_short |
Constraining kinetics of metastable olivine in the Marianas slab from seismic observations and dynamic models |
| title_full |
Constraining kinetics of metastable olivine in the Marianas slab from seismic observations and dynamic models |
| title_fullStr |
Constraining kinetics of metastable olivine in the Marianas slab from seismic observations and dynamic models |
| title_full_unstemmed |
Constraining kinetics of metastable olivine in the Marianas slab from seismic observations and dynamic models |
| title_sort |
constraining kinetics of metastable olivine in the marianas slab from seismic observations and dynamic models |
| url |
http://hdl.handle.net/20.500.12110/paper_00401951_v526-529_n_p48_Quinteros |
| work_keys_str_mv |
AT quinterosj constrainingkineticsofmetastableolivineinthemarianasslabfromseismicobservationsanddynamicmodels AT sobolevsv constrainingkineticsofmetastableolivineinthemarianasslabfromseismicobservationsanddynamicmodels |
| _version_ |
1807317825827635200 |