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Dynamics of Mantle and Lithosphere

Class at Faculty of Mathematics and Physics |
NGEO035

Syllabus

* Heat transport in continuum

Basic equations - mass, momentum and energy conservation, rheology, state equation, boundary conditions. Individual terms of heat equation (temperature changes, heat conduction and advection, adiabatic heating/cooling, viscous dissipation, heat sources).

* Thermal convection in the Earth mantle

Boussinesq approximation of basic equations. Dimensionless equations; Prandtl, Rayleigh and dissipation numbers. Boundary conditions. Static solution. Two-dimensional problem - stream function.

* Basic characteristics of thermal convection

Linearised theory - onset of convection. Style of convection as a function of Rayleigh number. Effects of internal heating, rheology, phase transitions and compressibility. Chaos.

* Parameters of heat equation

Thermal capacity and diffusivity, density, heat sources. Heat flux through the Earth surface.

* Temperature in the mantle and core

Adiabatic gradient, estimates of mantle temperature. Iron melting temperature and inner-core boundary temperature. Temperature jump across the D“.

* Hotspots

Distribution, origin. Interaction with the lithospheric plates. Reference system.

* Thermal models of oceanic lithosphere

Half-space model. Analytical solution, surface heat flux, ocean depth. Heat released in subduction zones.

* Earth radiactivity and geochronology

Alfa-, beta- and k-decay; P, Rb, Ar-methods; radiocarbon dating; age of the Earth.

* Cooling of the Earth

Parameterised convection, scaling relations. Solution of the heat equation with decaying radiogenic heat sources.

Annotation

Heat sources in the Earth. Basic equations of thermal convection.

Thermal convection as a nonlinear dynamic system. Thermal models of the Earth.

Radioactivity of the rocks, radiometric dating.