[S21-P] Poster

[S21-P-01] Formation of the Earth's lithosphere - asthenosphere surface initial heterogeneities

^○Yurii Khachai¹, Vsevolod Anfilogov², Alexandr Antipin³ (1.Institute of Geophysics UB RAS,Ekaterinburg,Russian Federation, 2.Institute of mineralogy UB RAS,Miass,Russian Federation, 3.Institute of Geophysics UB RAS,Ekaterinburg,Russian Federation)

The present interface between lithosphere and asthenosphere has a relief surface, as it is indicated by seismic and electromagnetic survey. This relief was formed over a long geological history of the planet. To understand the evolution of these structures it is needed the information about the initial state of the system, i.e., the state at the final stage of the Earth's formation. Here are presented the results of numerical modeling of non-uniform temperature distribution inside the three-dimensional model of the growing Earth at its final stage of dynamical formation. Namely those are heat and matter heterogeneities as objects that are recorded by the results of modern geophysical and geochemical studies. The simulation takes into account the random distribution of the falling bodies and particles, which are falling from the protoplanetary cloud. They are forming the initial distribution of temperature and composition heterogeneities. The evolution of heterogeneities during time is traced by using the numerical solution of boundary problem for a system of differential equations describing the change in mass of the growing planet using Safronov equation, matter flow using Navier-Stokes equations, movement of phase boundaries with use of Stefan problem. As it can be seen from the numerical results of the system solution, to the end of the planetary accumulation it is formed a relatively non-uniform thin crust and inside the upper mantle-the asthenosphere layer. In the mantle it is able to trace heterogeneous inclusions with sizes from the first to a few hundred kilometers with a complex interface. The upper boundary of the crust has also a complicated relief. The formed non-uniform thermal inclusions contribute to the formation of early bottom and upper mantle plumes. The dynamics of these plumes provide special metallogeny of cratons, which is no longer repeated in the geological history of the planet.
Those results are supported by the grant RFBR № 16-05-00540