The paper presents results derived from numerical modeling of mantle heating and reorganization of mantle flows during assemblage of two continents and subsequent breakup of the supercontinent. The simplest mantle model consisting of an extended rectangular region filled with a viscous fluid heated from below is considered. Thermal convection develops in the mantle. Due to viscosity dependence on temperature and pressure, a high viscosity lithosphere and a low viscosity asthenosphere arise in the mantle. Two continents modeled as rigid thick floating plates are then placed into the mantle. Driven by viscous coupling with mantle flows, the continents start moving and converge above the nearest descending mantle flow. The resulting supercontinent hinders the outflow of mantle heat, the subcontinental mantle starts heating, and the cold descending mantle flow gives way to a hot ascending flow. The latter assumes the shape of a plume with a spherical head and a thin tail. The resulting tensile stress breaks up the supercontinent. The Atlantic Ocean structure with a ridge and a lithosphere thickening toward continents forms between the diverging parts of the supercontinent. The calculated distribution of heat flux from the mantle has a maximum of about 200nbsp;mWnbsp;m-2 in the zone of the mid-ocean ridge and drops by about six times toward the continents, which agrees with data of observations. The Pacific Ocean structure with typical subduction zones develops on the opposite side of the continents. A high-viscosity mantle layer corresponding to continental lithosphere moves together with continents. The Atlantic Ocean structure persists for about 50-100nbsp;Myr, after which the heavy oceanic lithosphere separates from the continents and starts sinking into the mantle. Both continents are uplifted by a few hundred meters for about 50nbsp;Myr before and 50nbsp;Myr after the breakup of the supercontinent. This result is consistent with data on sea level fluctuations and can account for the duration of the Paleozoic, Mesozoic, and Cenozoic periods and for the origin of their changes.
Global geodynamics, Numerical modeling, Convection.
1. Anderson, Theory of the Earth, 1989.
2. Bobrov, J. Geodynamics,, v. 27, no. 1, 1999.
3. Fowler, The Solid Earth, 1996.
4. Khain, Basic Problems of Modern Geology, 1994.
5. Schubert, Mantle Convection in the Earth and Planets, 2001.
6. Scotese, Tectonophysics, v. 155, 1988.
7. Sepkoski, J. Geol. Soc., v. 144, 1987.
8. Trubitsyn, Izv. Phys. Solid Earth, v. 36, 2000.
9. Trubitsyn, Russian J. Earth Sci., v. 6, no. 5, 2004.
10. Trubitsyn, Mantle Convection with Thermally and Mechanically Coupled Floating Continents, 2002.
11. Trubitsyn, J. Geodynamics, v. 20, 1995.
12. Trubitsyn, 3-D spherical Models of Mantle Convection with Floating Continents, 2000.
13. Trubitsyn, Russian J. Earth Sci., v. 3, no. 2, 2001.
14. Trubitsyn, Int. Geol. Rev., v. 45, no. 6, 2003.
15. Turcotte, Geodynamics: Applications of Continuum Physics in Geological Problems, 1982.
16. Veil, Seismic Stratigraphy - Application to Hydrocarbon Exploration, 1977.
