Dynamically Supported Topography at the Earth’s Surface and the Core-Mantle-Boundary: Influences by a Depth-Dependent Thermal Expansivity and a Chemical Boundary Layer

  • D. C. Olbertz
  • U. Hansen
Chapter
Part of the NATO ASI Series book series (ASIC, volume 391)

Abstract

Two-dimensional time-dependent numerical simulations of the Earth’s mantle flow show that a chemical dense layer influences the dynamical behavior in the lower mantle. Decreasing thermal expansion coefficient a (as presumed by recent high-pressure experiments) enables dense material to remain within the transition zone between mantle and core (D″ -layer) without being entrained completely by the above mantle flow. Both phenomena—composition and depth-dependent α—affect the flow structure and therefore shape and amplitude of the topography at the surface and at the bottom of the convecting layer.

Keywords

Rayleigh Number Thermal Expansion Coefficient Dense Layer Bottom Topography Lower Mantle 
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Copyright information

© Springer Science+Business Media Dordrecht 1993

Authors and Affiliations

  • D. C. Olbertz
    • 1
  • U. Hansen
    • 1
  1. 1.Department of Geophysics, Institute of Earth SciencesUniversity of UtrechtUtrechtThe Netherlands

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