Magma Dynamics with the Enthalpy Method: Benchmark Solutions and Magmatic Focusing at Mid-ocean Ridges
Magma genesis and transport link mantle convection with surface volcanism and hence with the long-term chemical and morphological evolution of the Earth's crust. Modeling the dynamics of magma-mantle interaction in tectonic settings remains a challenge, however, because of the complexity of mul...
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| Format: | Journal article |
| Language: | English |
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2008
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| _version_ | 1826274181014093824 |
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| author | Katz, R |
| author_facet | Katz, R |
| author_sort | Katz, R |
| collection | OXFORD |
| description | Magma genesis and transport link mantle convection with surface volcanism and hence with the long-term chemical and morphological evolution of the Earth's crust. Modeling the dynamics of magma-mantle interaction in tectonic settings remains a challenge, however, because of the complexity of multi-component thermodynamics and melt segregation in a permeable, compactible, and actively deforming mantle matrix. Here I describe a flexible approach to formulating the thermochemistry of such models based on the Enthalpy Method, a technique commonly used in simulations of alloy solidification. This approach allows for melting and freezing based on a familiar binary phase diagram, consistent with conservation of energy and two-phase compaction and flow. I present an extension of the Enthalpy Method to more than two thermodynamic components. Simulation of a one-dimensional upwelling and melting column provides a benchmark for the method. Two-dimensional simulations of the melting region that feeds magma to a rapidly spreading mid-ocean ridge demonstrate the utility of the Enthalpy Method. These calculations provide a new estimate of the efficiency of magmatic focusing along the base of the oceanic lithosphere. Modeled focusing efficiency varies with mantle permeability and resistance to compaction. To yield 5-7 km of oceanic crust with ∼20% melting of a homogeneous, sub-ridge mantle, a focusing efficiency of greater than 70% is required. This, in turn, suggests that matrix permeability and bulk viscosity are at the high end of previously estimated values. © The Author 2008. Published by Oxford University Press. All rights reserved. |
| first_indexed | 2024-03-06T22:39:32Z |
| format | Journal article |
| id | oxford-uuid:5b0f1119-18df-4242-8882-fb92b1a5f242 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-06T22:39:32Z |
| publishDate | 2008 |
| record_format | dspace |
| spelling | oxford-uuid:5b0f1119-18df-4242-8882-fb92b1a5f2422022-03-26T17:19:46ZMagma Dynamics with the Enthalpy Method: Benchmark Solutions and Magmatic Focusing at Mid-ocean RidgesJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:5b0f1119-18df-4242-8882-fb92b1a5f242EnglishSymplectic Elements at Oxford2008Katz, RMagma genesis and transport link mantle convection with surface volcanism and hence with the long-term chemical and morphological evolution of the Earth's crust. Modeling the dynamics of magma-mantle interaction in tectonic settings remains a challenge, however, because of the complexity of multi-component thermodynamics and melt segregation in a permeable, compactible, and actively deforming mantle matrix. Here I describe a flexible approach to formulating the thermochemistry of such models based on the Enthalpy Method, a technique commonly used in simulations of alloy solidification. This approach allows for melting and freezing based on a familiar binary phase diagram, consistent with conservation of energy and two-phase compaction and flow. I present an extension of the Enthalpy Method to more than two thermodynamic components. Simulation of a one-dimensional upwelling and melting column provides a benchmark for the method. Two-dimensional simulations of the melting region that feeds magma to a rapidly spreading mid-ocean ridge demonstrate the utility of the Enthalpy Method. These calculations provide a new estimate of the efficiency of magmatic focusing along the base of the oceanic lithosphere. Modeled focusing efficiency varies with mantle permeability and resistance to compaction. To yield 5-7 km of oceanic crust with ∼20% melting of a homogeneous, sub-ridge mantle, a focusing efficiency of greater than 70% is required. This, in turn, suggests that matrix permeability and bulk viscosity are at the high end of previously estimated values. © The Author 2008. Published by Oxford University Press. All rights reserved. |
| spellingShingle | Katz, R Magma Dynamics with the Enthalpy Method: Benchmark Solutions and Magmatic Focusing at Mid-ocean Ridges |
| title | Magma Dynamics with the Enthalpy Method: Benchmark Solutions and Magmatic Focusing at Mid-ocean Ridges |
| title_full | Magma Dynamics with the Enthalpy Method: Benchmark Solutions and Magmatic Focusing at Mid-ocean Ridges |
| title_fullStr | Magma Dynamics with the Enthalpy Method: Benchmark Solutions and Magmatic Focusing at Mid-ocean Ridges |
| title_full_unstemmed | Magma Dynamics with the Enthalpy Method: Benchmark Solutions and Magmatic Focusing at Mid-ocean Ridges |
| title_short | Magma Dynamics with the Enthalpy Method: Benchmark Solutions and Magmatic Focusing at Mid-ocean Ridges |
| title_sort | magma dynamics with the enthalpy method benchmark solutions and magmatic focusing at mid ocean ridges |
| work_keys_str_mv | AT katzr magmadynamicswiththeenthalpymethodbenchmarksolutionsandmagmaticfocusingatmidoceanridges |