The Impact of Mélange Formation on the Rheology and H2O Budget of the Subduction Zone Interface, With Implications for Diapir Nucleation
Abstract At the subduction zone interface, a combination of mechanical deformation and (fluid‐mediated) chemical mixing of oceanic crust, sediment and mantle lithologies yields heterogeneous mélange lithologies. These mélanges have compositions and metamorphic mineral assemblages dissimilar to their...
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Wiley
2025-04-01
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| Series: | Geophysical Research Letters |
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| Online Access: | https://doi.org/10.1029/2024GL113049 |
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| author | Benjamin Z. Klein Mark D. Behn |
| author_facet | Benjamin Z. Klein Mark D. Behn |
| author_sort | Benjamin Z. Klein |
| collection | DOAJ |
| description | Abstract At the subduction zone interface, a combination of mechanical deformation and (fluid‐mediated) chemical mixing of oceanic crust, sediment and mantle lithologies yields heterogeneous mélange lithologies. These mélanges have compositions and metamorphic mineral assemblages dissimilar to their endmember source lithologies, resulting in a subduction zone interface with physical properties (e.g., H2O capacity, density, and viscosity) that are distinct from both the source lithologies and simple mechanical mixtures of these lithologies. Using phase equilibria modeling, we find that a large range of mélange compositions carry more H2O to sub‐arc depths and are less dense compared to equivalent mechanical mixtures. We further show that mélange is much weaker than the overlying mantle but remains stronger than quartzite deforming by dislocation creep. Lastly, we synthesize these results and find that at all subduction zones, a range of mélange compositions are likely to form diapirs at sub‐arc depths and sub‐solidus temperatures. |
| format | Article |
| id | doaj-art-a9d1a3e0fa10484fa03ea2898ed972f5 |
| institution | Kabale University |
| issn | 0094-8276 1944-8007 |
| language | English |
| publishDate | 2025-04-01 |
| publisher | Wiley |
| record_format | Article |
| series | Geophysical Research Letters |
| spelling | doaj-art-a9d1a3e0fa10484fa03ea2898ed972f52025-08-20T03:49:45ZengWileyGeophysical Research Letters0094-82761944-80072025-04-01527n/an/a10.1029/2024GL113049The Impact of Mélange Formation on the Rheology and H2O Budget of the Subduction Zone Interface, With Implications for Diapir NucleationBenjamin Z. Klein0Mark D. Behn1Insititute of Earth Science University of Lausanne Lausanne SwitzerlandDepartment of Earth and Environmental Sciences Boston College Chestnut Hill MA USAAbstract At the subduction zone interface, a combination of mechanical deformation and (fluid‐mediated) chemical mixing of oceanic crust, sediment and mantle lithologies yields heterogeneous mélange lithologies. These mélanges have compositions and metamorphic mineral assemblages dissimilar to their endmember source lithologies, resulting in a subduction zone interface with physical properties (e.g., H2O capacity, density, and viscosity) that are distinct from both the source lithologies and simple mechanical mixtures of these lithologies. Using phase equilibria modeling, we find that a large range of mélange compositions carry more H2O to sub‐arc depths and are less dense compared to equivalent mechanical mixtures. We further show that mélange is much weaker than the overlying mantle but remains stronger than quartzite deforming by dislocation creep. Lastly, we synthesize these results and find that at all subduction zones, a range of mélange compositions are likely to form diapirs at sub‐arc depths and sub‐solidus temperatures.https://doi.org/10.1029/2024GL113049subduction zonemélangediapirismphase equilibriaH2O budget |
| spellingShingle | Benjamin Z. Klein Mark D. Behn The Impact of Mélange Formation on the Rheology and H2O Budget of the Subduction Zone Interface, With Implications for Diapir Nucleation Geophysical Research Letters subduction zone mélange diapirism phase equilibria H2O budget |
| title | The Impact of Mélange Formation on the Rheology and H2O Budget of the Subduction Zone Interface, With Implications for Diapir Nucleation |
| title_full | The Impact of Mélange Formation on the Rheology and H2O Budget of the Subduction Zone Interface, With Implications for Diapir Nucleation |
| title_fullStr | The Impact of Mélange Formation on the Rheology and H2O Budget of the Subduction Zone Interface, With Implications for Diapir Nucleation |
| title_full_unstemmed | The Impact of Mélange Formation on the Rheology and H2O Budget of the Subduction Zone Interface, With Implications for Diapir Nucleation |
| title_short | The Impact of Mélange Formation on the Rheology and H2O Budget of the Subduction Zone Interface, With Implications for Diapir Nucleation |
| title_sort | impact of melange formation on the rheology and h2o budget of the subduction zone interface with implications for diapir nucleation |
| topic | subduction zone mélange diapirism phase equilibria H2O budget |
| url | https://doi.org/10.1029/2024GL113049 |
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