Limites convergentes: zonas de subduccion. Prismas de acrecion, arcos magmaticos

Plate tectonics Convergentboundaries

Plate tectonics Convergentboundaries Collision

Subduction

Subduction modeling

From 2D to 3D…

Subduction modeling

About the plate tectonics 2D subduction model 3D subduction model Future works

Subduction modeling

About the plate tectonics 2D subduction model 3D subduction model Future works

Subduction modeling

About the plate tectonics 2D subduction model 3D subduction model Future works

First subduction model : 2D

Rectangle domain

Plate

Upper mantle

First subduction model : 2D

Lengths of the domain

3120 km

660 kmPlate

Upper mantle

Lower mantle

100 km

First subduction model : 2D

Boundary conditions

No slip

Plate

Upper mantle

Lower mantle

First subduction model : 2D

Boundary conditions

No slip

Plate

Upper mantle

Lower mantle

Free slip

First subduction model : 2D

Boundary conditions

No slip

Plate

Upper mantle

Lower mantle

Free slip

Free slip Free slip

First subduction model : 2D

Boundary conditions

No slip

Plate

Upper mantle

Lower mantle

Free slip

Free slip Free slip

No slip

Governing equations

Rayleigh-Taylor Instability: dense slab sinks into a less dense mantle

0v

… conservation of mass, incompressible medium

gp

i

j

j

iij x

v

x

v

… conservation of momentum

… deviatoric stress tensorwith

no energy equation

Rheology

Viscous mantle

Viscoplastic plate

.constmantle

yieldcreepyield

yieldcreepcreep

II

yieldyield e2

IIcreepcreep e 2

Viscous Plastic

The hardware: Horus supercomputer

2D subduction results

Lifecycle : flow reorganization

Necessity of the third dimension

Importance of the mantle flow Real subductions have a limited lateral

extent Interactions on the lateral edges of

subduction zones

Subduction modeling

About the plate tectonics 2D subduction model 3D subduction model Future works

3D subduction model

Same governing equations Same tools used … only a different setup

3D subduction model

upper mantle

plate with subduction zone

no upper plate

Box size: big enough, for side walls to have little effect on subducting slab

The level set field

subducting slab

only subducting part of the plate is included in the FE domain

use level set to define and track the subducting plate

Symmetry hypothesis

assume symmetry: model only half of the domain

free slip side boundary

Bottom boundary condition

higher viscosity in LM and phase boundary hinder convection

fixed bottom boundary

Slab boundary conditions

plate fixed, to isolate effects of tearing and rollback

fixedend

free slip top boundary

Edge of the slab

extreme case:free sliptear zone

Top boundary condition

plate bottom fixed

Sides boundary conditions

Freeslip onthe sides

3D subduction results

Lifecycle of the subduction

Reorganization of the flow