Relative impact of mantle densification and eclogitization of slabs on subduction dynamics: A numerical thermodynamic/thermokinematic investigation of metamorphic density evolution
Understanding the relationships between density and spatio-thermal variations at convergent plate boundaries is important for deciphering the present-day dynamics and evolution of subduction zones. In particular, the interaction between densification due to mineralogical phase transitions and slab p...
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2014
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paper:paper_00401951_v637_n_p20_Duesterhoeft2023-06-08T15:04:00Z Relative impact of mantle densification and eclogitization of slabs on subduction dynamics: A numerical thermodynamic/thermokinematic investigation of metamorphic density evolution Quinteros, Javier Density Melt Metamorphism Subduction Thermo-mechanical modeling Thermodynamic modeling Densification Densification Density (specific gravity) Density (specific gravity) Melting Melting Phase transitions Phase transitions Structural geology Structural geology Tectonics Tectonics Thermodynamics Thermodynamics Convergent plate boundaries Convergent plate boundaries Metamorphic structures Metamorphic structures Metamorphism Metamorphism Subduction Subduction Subduction zone modeling Subduction zone modeling Thermodynamic equilibria Thermodynamic equilibria Thermodynamic model Thermodynamic model Thermomechanical model Thermomechanical model Metamorphic rocks mantle structure metamorphism plate boundary plate convergence slab subduction zone thermodynamics Understanding the relationships between density and spatio-thermal variations at convergent plate boundaries is important for deciphering the present-day dynamics and evolution of subduction zones. In particular, the interaction between densification due to mineralogical phase transitions and slab pull forces is subject to ongoing investigations. We have developed a two-dimensional subduction zone model that is based on thermodynamic equilibrium assemblage calculations and includes the effects of melting processes on the density distribution in the lithosphere. Our model calculates the "metamorphic density" of rocks as a function of pressure, temperature and chemical composition in a subduction zone down to 250. km. We have used this model to show how the hydration, dehydration, partial melting and fractionation processes of rocks all influence the metamorphic density and greatly depend on the temperature field within the subduction system. These processes are largely neglected by other approaches that reproduce the density distribution within this complex tectonic setting. Our model demonstrates that the initiation of eclogitization (i.e., when crustal rocks reach higher densities than the ambient mantle) of the slab is not the only significant process that makes the descending slab denser and generates the slab pull force. Instead, the densification of the lithospheric mantle of the sinking slab starts earlier than eclogitization and contributes significantly to slab pull in the early stages of subduction. Accordingly, the complex metamorphic structure of the slab and the mantle wedge has an important impact on the development of subduction zones. © 2014 Elsevier B.V. Fil:Quinteros, J. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 2014 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00401951_v637_n_p20_Duesterhoeft http://hdl.handle.net/20.500.12110/paper_00401951_v637_n_p20_Duesterhoeft |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
Density Melt Metamorphism Subduction Thermo-mechanical modeling Thermodynamic modeling Densification Densification Density (specific gravity) Density (specific gravity) Melting Melting Phase transitions Phase transitions Structural geology Structural geology Tectonics Tectonics Thermodynamics Thermodynamics Convergent plate boundaries Convergent plate boundaries Metamorphic structures Metamorphic structures Metamorphism Metamorphism Subduction Subduction Subduction zone modeling Subduction zone modeling Thermodynamic equilibria Thermodynamic equilibria Thermodynamic model Thermodynamic model Thermomechanical model Thermomechanical model Metamorphic rocks mantle structure metamorphism plate boundary plate convergence slab subduction zone thermodynamics |
| spellingShingle |
Density Melt Metamorphism Subduction Thermo-mechanical modeling Thermodynamic modeling Densification Densification Density (specific gravity) Density (specific gravity) Melting Melting Phase transitions Phase transitions Structural geology Structural geology Tectonics Tectonics Thermodynamics Thermodynamics Convergent plate boundaries Convergent plate boundaries Metamorphic structures Metamorphic structures Metamorphism Metamorphism Subduction Subduction Subduction zone modeling Subduction zone modeling Thermodynamic equilibria Thermodynamic equilibria Thermodynamic model Thermodynamic model Thermomechanical model Thermomechanical model Metamorphic rocks mantle structure metamorphism plate boundary plate convergence slab subduction zone thermodynamics Quinteros, Javier Relative impact of mantle densification and eclogitization of slabs on subduction dynamics: A numerical thermodynamic/thermokinematic investigation of metamorphic density evolution |
| topic_facet |
Density Melt Metamorphism Subduction Thermo-mechanical modeling Thermodynamic modeling Densification Densification Density (specific gravity) Density (specific gravity) Melting Melting Phase transitions Phase transitions Structural geology Structural geology Tectonics Tectonics Thermodynamics Thermodynamics Convergent plate boundaries Convergent plate boundaries Metamorphic structures Metamorphic structures Metamorphism Metamorphism Subduction Subduction Subduction zone modeling Subduction zone modeling Thermodynamic equilibria Thermodynamic equilibria Thermodynamic model Thermodynamic model Thermomechanical model Thermomechanical model Metamorphic rocks mantle structure metamorphism plate boundary plate convergence slab subduction zone thermodynamics |
| description |
Understanding the relationships between density and spatio-thermal variations at convergent plate boundaries is important for deciphering the present-day dynamics and evolution of subduction zones. In particular, the interaction between densification due to mineralogical phase transitions and slab pull forces is subject to ongoing investigations. We have developed a two-dimensional subduction zone model that is based on thermodynamic equilibrium assemblage calculations and includes the effects of melting processes on the density distribution in the lithosphere. Our model calculates the "metamorphic density" of rocks as a function of pressure, temperature and chemical composition in a subduction zone down to 250. km. We have used this model to show how the hydration, dehydration, partial melting and fractionation processes of rocks all influence the metamorphic density and greatly depend on the temperature field within the subduction system. These processes are largely neglected by other approaches that reproduce the density distribution within this complex tectonic setting. Our model demonstrates that the initiation of eclogitization (i.e., when crustal rocks reach higher densities than the ambient mantle) of the slab is not the only significant process that makes the descending slab denser and generates the slab pull force. Instead, the densification of the lithospheric mantle of the sinking slab starts earlier than eclogitization and contributes significantly to slab pull in the early stages of subduction. Accordingly, the complex metamorphic structure of the slab and the mantle wedge has an important impact on the development of subduction zones. © 2014 Elsevier B.V. |
| author |
Quinteros, Javier |
| author_facet |
Quinteros, Javier |
| author_sort |
Quinteros, Javier |
| title |
Relative impact of mantle densification and eclogitization of slabs on subduction dynamics: A numerical thermodynamic/thermokinematic investigation of metamorphic density evolution |
| title_short |
Relative impact of mantle densification and eclogitization of slabs on subduction dynamics: A numerical thermodynamic/thermokinematic investigation of metamorphic density evolution |
| title_full |
Relative impact of mantle densification and eclogitization of slabs on subduction dynamics: A numerical thermodynamic/thermokinematic investigation of metamorphic density evolution |
| title_fullStr |
Relative impact of mantle densification and eclogitization of slabs on subduction dynamics: A numerical thermodynamic/thermokinematic investigation of metamorphic density evolution |
| title_full_unstemmed |
Relative impact of mantle densification and eclogitization of slabs on subduction dynamics: A numerical thermodynamic/thermokinematic investigation of metamorphic density evolution |
| title_sort |
relative impact of mantle densification and eclogitization of slabs on subduction dynamics: a numerical thermodynamic/thermokinematic investigation of metamorphic density evolution |
| publishDate |
2014 |
| url |
https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00401951_v637_n_p20_Duesterhoeft http://hdl.handle.net/20.500.12110/paper_00401951_v637_n_p20_Duesterhoeft |
| work_keys_str_mv |
AT quinterosjavier relativeimpactofmantledensificationandeclogitizationofslabsonsubductiondynamicsanumericalthermodynamicthermokinematicinvestigationofmetamorphicdensityevolution |
| _version_ |
1768543647734693888 |