1 / 11

also:

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. Conservation Equations. Dimensionless Parameters.

makayla-gavaghan
Download Presentation

also:

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  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.org • 12x483 or 12x643 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. Model Data 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

  10. CMB heat flux lower mantle temperature Heat flux histories

More Related