Structure of Mantle Convection: Plumes and Plates Anne Davaille, (FAST, CNRS / Univ. Paris-Sud, Orsay, France) Michael Le Bars, Sophie Androvandi, Cecilia Cadio, Judith Vatteville, Valérie Vidal, Eléonore Stutzmann, Jean Besse, Isabelle Panet, Vincent Courtillot (IPGP) Erika Di Giuseppe, Eric Mittelstaedt, Aurore Sibrant (FAST) ,Ichiro Kumagai, Kei Kurita (ERI, Tokyo), Sue Smrekar (JPL, USA), Nick Arndt (ISTerre, Gernoble) Collège de France – 25-26 juin 2018 A B A B 35 mm The view of a physicist … = provide a framework to predict and to interpret the observations
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Structure of Mantle Convection: Plumes and Plates...Structure of Mantle Convection: Plumes and Plates Anne Davaille, (FAST, CNRS / Univ. Paris-Sud, Orsay, France)Michael Le Bars, Sophie
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Structure of Mantle Convection:Plumes and Plates
Anne Davaille, (FAST, CNRS / Univ. Paris-Sud, Orsay, France)Michael Le Bars, Sophie Androvandi, Cecilia Cadio, Judith Vatteville, Valérie Vidal, Eléonore
Stutzmann, Jean Besse, Isabelle Panet, Vincent Courtillot (IPGP)Erika Di Giuseppe, Eric Mittelstaedt, Aurore Sibrant (FAST)
,Ichiro Kumagai, Kei Kurita (ERI, Tokyo), Sue Smrekar (JPL, USA), Nick Arndt (ISTerre, Gernoble)
5- Making a plate: Convectionwith strongly Tp-dependent viscosity
5- Making a plate: Convectionwith strongly Tp-dependent viscosity
Highviscosity ratio=>Plate
5- Making a plate: Convectionwith strongly Tp-dependent viscosity
5- Making a plate: Convectionwith strongly Tp-dependent viscosity
Strong influenceofdownwellingsonplumestability andgeneration area
-3.0 -2.0 -1.0 -0.2 0.2 1.0 2.0 3.0
5- Making a plate: Convectionwith strongly Tp-dependent viscosity
Strong influenceofdownwellingsonplumestability andgeneration area
-3.0 -2.0 -1.0 -0.2 0.2 1.0 2.0 3.0
=> How to break the lid ?
5- Making a plate: Convectionwith strongly Tp-dependent viscosity
Ex: Yield stress + viscosity decrease under the plates due to melting(Tackley 2000)
Viscosity field Cold isotherm
6- Non-newtonian rheology: « Kick Hard to Break »
Moresi and Solomatov, 1998Regenauer-Lieb et al., 2001Solomatov, 2004Stein & al, 2004Enns et al., 2005Stegman et al., 2006Ueda et al., 2008Gerya et al., 2008Thielmann & Kaus, 2014…
+shear heating ,+pre-existing weaknesses ,+…
.Localize deformation => plates
.Instantaneous rheology=> require yield stress much lower than measured…