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Magma-Lithosphere Interaction Magma-Lithosphere Interaction Chris Havlin1 ([email protected]) Ben Holtzman1, Jim Gaherty1, Patty Lin1, Terry Plank1, Sara Mana1, Natalie Accardo1, Roger Buck1 Mousumi Roy2, Marc Parmentier3, Greg Hirth3, Karen Fischer3, 1. Lamont-Doherty Earth Observatory; 2. University of New Mexico; 3. Brown University Holtzman and Kendall, G3, 2010 Magma-Lithosphere Interaction Melt Transport fracture propagation (magma chambers, dikes, sills, fault-interaction, eruptions) crust mantle lith. coupling somewhere between? porous flow (in a viscously deforming matrix) Magma-Lithosphere Interaction Melt Transport Lithosphere Inheritance: fracture propagation shear zones (magma chambers, dikes, sills, fault-interaction, grain size? eruptions) fabric? crust mantle lith. lith. thickness coupling somewhere depleted ?? between? dry porous flow (in a viscously refertilization? deforming matrix) (metasomatism) Magma-Lithosphere Interaction Melt Transport Lithosphere Inheritance: fracture propagation shear zones (magma chambers, dikes, sills, fault-interaction, grain size? eruptions) fabric? crust mantle lith. lith. thickness coupling somewhere depleted ?? between? + dry + porous flow (in a viscously refertilization? deforming matrix) (metasomatism) Magma-Lithosphere Interaction Melt Transport Lithosphere Inheritance: I. lithosphere inheritance and fracture propagation shear zones melt migration, accumulation, (magma chambers, grain size? infiltration dikes, sills, fault-interaction, eruptions) fabric? crust II. Intrusional heating mantle lith. lith. thickness coupling somewhere depleted III. Thermal-chemical-mechanical ?? between? + dry feedbacks (in the mantle lith.) + IV. Geophysics and the quest porous flow for melt (in a viscously refertilization? deforming matrix) (metasomatism) Magma-Lithosphere Interaction Melt Transport Lithosphere Inheritance: I. lithosphere inheritance and fracture propagation shear zones melt migration, accumulation, (magma chambers, grain size? infiltration dikes, sills, fault-interaction, eruptions) fabric? crust II. Intrusional heating mantle lith. lith. thickness coupling somewhere depleted III. Thermal-chemical-mechanical ?? between? + dry feedbacks (in the mantle lith.) + IV. Geophysics and the quest porous flow for melt (in a viscously refertilization? deforming matrix) (metasomatism) Magma-Lithosphere Interaction Melt Transport Lithosphere Inheritance: I. lithosphere inheritance and fracture propagation shear zones melt migration, accumulation, (magma chambers, grain size? infiltration dikes, sills, fault-interaction, eruptions) fabric? crust II. Intrusional heating mantle lith. lith. thickness coupling somewhere depleted III. Thermal-chemical-mechanical ?? between? + dry feedbacks (in the mantle lith.) + IV. Geophysics and the quest porous flow for melt (in a viscously refertilization? deforming matrix) (metasomatism) Magma-Lithosphere Interaction Melt Transport Lithosphere Inheritance: I. lithosphere inheritance and fracture propagation shear zones melt migration, accumulation, (magma chambers, grain size? infiltration dikes, sills, fault-interaction, eruptions) fabric? crust II. Intrusional heating mantle lith. lith. thickness coupling somewhere depleted III. Thermal-chemical-mechanical ?? between? + dry feedbacks (in the mantle lith.) + IV. Geophysics and the quest porous flow for melt (in a viscously refertilization? deforming matrix) (metasomatism) Magma-Lithosphere Interaction Melt Transport Lithosphere Inheritance: I. lithosphere inheritance and fracture propagation shear zones melt migration, accumulation, (magma chambers, grain size? infiltration dikes, sills, fault-interaction, eruptions) fabric? crust II. Intrusional heating mantle lith. lith. thickness coupling somewhere depleted III. Thermal-chemical-mechanical ?? between? + dry feedbacks (in the mantle lith.) + IV. Geophysics and the quest porous flow for melt (in a viscously refertilization? deforming matrix) (metasomatism) Shallow magma-lithosphere interaction Strain accomodation/localization, rift segmentation (e.g., Muirhead et al., G3,2015; Corti et al., Tectonophysics 2002; Ebinger and Casey, Geology 2001;) Dikes, faults and stress (e.g, Hamling et al., Nature Geo., 2010; Nobile et al., GRL 2012; Bedard, GSA Bulletin, 2012) Magma-Lithosphere Interaction Melt Transport Lithosphere Inheritance: I. lithosphere inheritance and fracture propagation shear zones melt migration, accumulation, (magma chambers, grain size? infiltration dikes, sills, fault-interaction, eruptions) fabric? crust II. Intrusional heating mantle lith. lith. thickness coupling somewhere depleted III. Thermal-chemical-mechanical ?? between? + dry feedbacks (in the mantle lith.) + IV. Geophysics and the quest porous flow for melt (in a viscously refertilization? deforming matrix) (metasomatism) Melt: where does it go? Fluid velocity: pressure gradients driving segregation compaction pressure dynamic pressure (matrix shear, stokes) surface tension porosity permeability (n between 2,3... 2.6 Miller et al., EPSL 2014) melt-buoyancy fluid shear viscosity Lithosphere Thickness: Melt Focusing & Decompaction Channels 40 (d) solidus-geotherm intersection 60 (impermeable) 80 z [km] buoyancy 100 120 140 (de)compaction Sparks and Parmentier, EPSL 1991 Spiegelman, Phil. Trans. 1993 0 20 40 60 80 100 Katz, G3 2010 x [km] −3 −2.5 −2 −1.5 Amount of focusing depends on how "leaky" the boundary is Havlin et al., in prep. Lithosphere pressure gradients and melt transport Roy et al., in review Dynamic pressure gradients (matrix shear, stokes flow) Spiegelman and McKenzie, EPSL 1987 melt Phipps Morgan, GRL 1987 extraction 0 500 100 Strong lithospheric keel 400 moving relative to asthenosphere: Roy et al., in review 350 red curves - melt streamlines 300 arrows - solid flow field contour - temperature 250 melt deflected towards margins 200 km 150 100 50 0 0 200 400 600 800 1000 km Inherited heterogeneity and shear zones: pathways for melt? Gulf of Aden Grain size and surface tension: Afars smaller grains = more grains in a given volume 1. higher porosity 2. higher surface area for reactions D1 D2 0° Tanzania craton A’ Wark and Watson, GRL, 2000 Congo LV crat on A Lithology? More fusible? Zambia block Indian Zimbabwe Ocean -20° craton 30° 50° Vauchez et al., EPSL, 2005 Gulf of Aden Afars 0° Tanzania craton A’ Congo LV crat on A Zambia block Indian Zimbabwe Ocean -20° craton 30° 50° Vauchez et al., EPSL, 2005 Magma-Lithosphere Interaction Melt Transport Lithosphere Inheritance: I. lithosphere inheritance and fracture propagation shear zones melt migration, accumulation, (magma chambers, grain size? infiltration dikes, sills, fault-interaction, eruptions) fabric? crust II. Intrusional heating mantle lith. lith. thickness coupling somewhere depleted III. Thermal-chemical-mechanical ?? between? + dry feedbacks (in the mantle lith.) + IV. Geophysics and the quest porous flow for melt (in a viscously refertilization? deforming matrix) (metasomatism) Dike transport: intrusional heating "Whole-lithosphere" heating (dike height: 10s of km) "Basal" heating (dike height << 10 km) Dike transport: intrusional heating "Whole-lithosphere" heating (dike height: 10s of km) Bialis, Buck and Qin, EPSL, 2010 Time (Myr) Also: Schmeling, Tectonophysics, 2010 Schmeling and Wallner, G3, 2012 "Basal" heating (dike height << 10 km) Dike transport: intrusional heating "Whole-lithosphere" heating (dike height: 10s of km) Bialis, Buck and Qin, EPSL, 2010 Time (Myr) Also: Schmeling, Tectonophysics, 2010 Schmeling and Wallner, G3, 2012 "Basal" heating (dike height << 10 km) Dike propagation from melt accumulation zone at low (<0.25) melt fraction (c) (a) (c) (d) (b) Havlin, Parmentier and Hirth, EPSL, 2013 Dike transport: intrusional heating "Whole-lithosphere" heating higher (dike height: 10s of km) whole-lithosphere heating whole-lithosphere initial plume impact, (flood basalts!) Bialis, Buck and Qin, EPSL, 2010 Time (Myr) Also: Schmeling, Tectonophysics,standard 2010 decompression Schmeling and Wallner, G3, 2012 (upwelling in plume tail, "Basal" heating (dike height << 10 km) passive upwelling) basal heating Dike propagation from melt accumulation zone at low (<0.25) melt fraction (c) (a) (d) (c) melt generation/accumulation rate small scale convection (b) lower Havlin, Parmentier and Hirth, EPSL, 2013 Basal heating (Havlin et al., in prep.) Dry Perid. 0 Solidus Intrusional heating at the LAB: 20 1. Geotherm heated to solidus 2. Porosity front advances 40 60 z [km] 80 100 Temperature Porosity Viscosity 120 18 20 22 24 26 0 500 1000 1500 0 0.01 0.0210 10 10 10 10 T [oC] φ η [Pa s] Basal heating (Havlin et al., in prep.) Dry Perid. 0 Solidus Intrusional heating at the LAB: 20 1. Geotherm heated to solidus 2. Porosity front advances 40 60 z [km] 80 100 Temperature Porosity Viscosity 120 18 20 22 24 26 0 500 1000 1500 0 0.01 0.0210 10 10 10 10 T [oC] φ η [Pa s] Basal heating (Havlin et al., in prep.) Dry Perid. 0 Solidus 1D Intrusional heating at the LAB 20 1. Geotherm heated to solidus 40 2. Porosity front advances 30 60 40 z [km] 1550 1475 50 80 60 z [km] 100 70 80 1400 Temperature Porosity Viscosity 90 120 18 20 22 24 26 0 2 4 6 8 10 0 500 1000 1500 0 0.01 0.0210 10 10 10 10 t [Myrs] T [oC] φ η [Pa s] Basal heating (Havlin et al., in prep.) Dry Perid. 0 Solidus 1D Intrusional heating at the LAB 20 1. Geotherm heated to solidus 40 2. Porosity front advances 30 60 40 z [km] 1550 1475 50 80 60 z [km] 100 70 80 1400 Temperature Porosity Viscosity 90 120 18 20 22 24 26 0 2 4 6 8 10 0 500 1000 1500 0 0.01 0.0210 10 10 10 10 t [Myrs] T [oC] φ
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