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Questions about Subduction approachable with geophysics, field study, laboratory study

This interdisciplinary approach delves into subduction zones through geophysical, geochemical, field, and laboratory studies to understand processes such as devolatilization, buoyancy, and seismic activity. Learn about water content in incoming mantle and explore various subduction zones like Nicaragua, Lombok, Tonga, Costa Rica, and Chile. Discover insights on magma formation, fluid flow, rock deformations, and material recycling in active and fossil arcs worldwide.

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Questions about Subduction approachable with geophysics, field study, laboratory study

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  1. Questions about Subductionapproachable with geophysics,field study, laboratory study

  2. How Much H2O in Incoming Mantle? → rxn rates & locations (devolatilization), buoyancy, earthquakes(?) Nicaragua: 10 km of 15% serpentine Lombok: 5 km of 20% serpentine Tonga: 24 km of 30% serpentine Planert et al. [2010] Ivandicet al. [2010]; Lefeldt et al. [2012] Contreras-Reyeset al. [2011] Costa Rica: 5 km of ≤30% serpentine Chile: 7 km alteration Tonga: ≤8 kmof 60% serpentine Contreras-Reyeset al. [2008] Savage [2012] van Avendonk et al. [2011]

  3. Melt Beneath the Outer Rise? → LAB, forearc volcanism, slab volatiles Hawley et al. (2016) Worzewski et al. (2011) Costa Rica

  4. How Do Fluid & Melt Flow in Wedge? → refertilization, arc magmatism, buoyancy, flow, anisotropy, etc. Nakahigashi et al. (2015) Wilson et al. (2014)

  5. Are Noses Wet? Ryukyu → buoyancy, flow, anisotropy, storage… Abers et al. (in review) isotropic Vp Nagaya et al. (2016) S-wave splitting (anisotropic) few brucite studies; one terrane has 20% (Kawahara et al., 2016)

  6. What Makes a Slow Supra-Slab Layer? → buoyancy, flow, anisotropy, H2O storage, K-magmatism, etc. VS RF reflectivity (Kawakatsu & Watada, 2007) slow crust to 80–90 km 39.5°N Tohoku Moho ΔVs ~+6%

  7. Why is Wedge Conductive? → buoyancy, anisotropy, H2O storage, magmatism Cascadia chlorite → magnetite; but, used Mg#25 chlorite Manthilake et al. (2016) fluid cannot explain anomalous conductivity fluid/melt (McGary et al., 2014)

  8. How Do Noses Deform? by flow? cracking? what is effect of fluids? what is effect on fluids? Escartin et al. (2001); Proctor & Hirth (2016) Nagaya et al. (2016) brittle ductile brittle ductile talc? chlorite? brucite?

  9. What Causes Slow-Slip Events? long-term SSE in W Shikoku because colder slab & thinner crust stabilize brucite (Mizukami et al., 2016)

  10. Is Subducted Carbon Recycled? 20−80% (Dasgupta & Hirschmann, 2010) ≤100% subducted C relaminates upper plate diapirically (Kelemen & Manning, 2015) Kelemen & Manning (2015) Behn et al. (2011)

  11. Is Continental Crust Recycled? <40% of new CC is being recycled(Hacker et al., 2011) ≥100% of new CC is being recycled(Stern & Scholl, 2011) 0% CC has been recycled(Hofmann et al., 2016)

  12. Does Slab Material Transit Wedge? inherited zircons in Cretaceous Cuba arc from subducted sediment (Rojas-Agramonte et al., 2016)

  13. Where are the Wedge Diapirs? Currie et al. (2014) Vogt et al. (2012) Gerya & Meilick (2011) slow density increase or low-viscosity root rapid density increase or high-viscosity root

  14. An Interdisciplinary Approach • geophysical study of active arcs • proxies for slab & wedge fluid, melt, flow • geochemical study of active & fossil arcs • proxies for material cycling • field study of exhumed rocks worldwide • rock record of processes that occurred • laboratory study of rocks & minerals • measure physical properties, incl. deformation

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