1. also: Shijie Objective: reconstruct the mantle from 450Ma to the present-day using a numerical model of mantle convection that includes plate motion history, with a focus on heat flow at the surface and the core-mantle boundary

2. Conservation Equations Dimensionless Parameters

3. Boundary Conditions Surface: Isothermal, prescribed plate velocity history Core-mantle boundary (CMB): Isothermal, free-slip Initial Conditions 1D thermal profile derived from free convection pre-calculation 250 km thick chemically dense layer above the CMB Numerical Method CitcomS spherical mantle convection community code www.geodynamics.orgwww.geodynamics.org 12x48 3 or 12x64 3 finite elements Ra adjusted to give rms free convective velocity = rms plate velocity ~ 6 cm/yr

4. Plate Motion History free convection stage with stress free surface ~ 200 Myr (for thermal equilibration) 460 - 390 Ma: Laurasia, Gondwana + 4 PaleoPacific plates (stage) 390 - 330 Ma: Laurasia, Gondwana + 4 PaleoPacific plates (stage) 330-255 Ma: Pangea + + 4 PaleoPacific plates (stage) 255 - 195 Ma: Pangea + 4 PaleoPacific plates (stage) 195 - 152 Ma: Pangea, NeoTethys + 4 PaleoPacific plates (stage) 152 - 119 Ma: North Am, South Am, Eurasia, Africa-India, Antarctica-Australia + 4 PaleoPacific plates (stage) 119 Ma – present-day: multi-stage evolution Plate data: 460-119 Ma: Scotese (2001) 119-0 Ma: Lithgow-Bertelloni & Richards (1998)

5. Model Inputs Model Outputs Mantle state: temperature, pressure, stress, strain-rate, viscosity, composition… Crustal state: surface heat flow, topography (dynamic + static), crustal age (via tracers) CMB heat flow, topography Mantle tracers (passive and active)

6. Data Model Surface Heat Flow Crustal Age

7. Model Cases

8. Surface & Core-Mantle Boundary Heat Flow

9. Surface Heat Flow and Crustal Age Patterns by Epoch

11. CMB heat flux lower mantle temperature Heat flux histories