Tectonic depressions on the East-European and Siberian platforms: numerical modeling of convection beneath the Eurasian continent

• Published in: Geodynamics & Tectonophysics
• Main Authors: V. V. Chervov, N. A. Bushenkova, G. G. Chernykh, В. В. Червов, Н. А. Бушенкова, Г. Г. Черных
• Other Authors: The study received a partial financial support under Interdisciplinary Integration Project of SB RAS 44 and the State Assignment Project 0331-2019-0010., Работа выполнена при частичной финансовой поддержке Междисциплинарного интеграционного проекта СО РАН № 44 и Госзадания № 0331-2019-0010.
• Format: Article in Journal/Newspaper
• Language: Russian
• Published: Institute of the Earth's crust of the Russian Academy of Sciences, Siberian Branch 2021
• Subjects: платформа; mathematical modeling; mantle; lithosphere thickness; craton; depression; syneclise; platform; математическое моделирование; мантия; мощность литосферы; кратон; прогиб; синеклиза; Arctic
• Online Access: https://www.gt-crust.ru/jour/article/view/1166; https://doi.org/10.5800/GT-2021-12-1-0514

In modern concepts, the upper mantle of the Earth is a highly viscous incompressible liquid, and its flow is described using the Navier – Stokes equations in the Oberbeck – Boussinesq and geodynamic approximations. Convective flows in the upper mantle play a decisive role in the kinematics of lithospheric plates and the geological history of continental regions. Mathematical modeling is a basic method for studying convective processes in the mantle. Our paper presents a numerical model of convection, which is based on the implicit artificial compressibility method. This model is tested in detail by comparing our calculation results with the results of a well-known international test. It is demonstrated that the Fedorenko grids sequence method is highly efficient and reduces the computing time almost by a factor of eight. The numerical model is generalized in order to state the problem in a spherical system of coordinates. It is used to analyse the distribution of convective flows in the upper mantle underneath the Eurasian continent. The analysis shows that the thickness and geometrical parameters of the lithospheric blocks are the factors of significant influence on the distribution of convective flows in the upper mantle. The resulting structure of convective flows is manifested in the surface topography of large platform areas wherein the lithosphere thickness is increased. Thus, the locations of extended downward convection flows under the East European and Siberian platforms are clearly comparable to syneclises observed in the study area. В соответствии с современными представлениями верхняя мантия Земли рассматривается как высоковязкая несжимаемая жидкость, для описания течения которой привлекаются уравнения Навье – Стокса в приближении Обербека – Буссинеска и геодинамическом приближении. Конвективные течения в верхней мантии Земли играют определяющую роль в кинематике литосферных плит и геологической истории развития континентальных областей. Основным методом исследования конвективных процессов в мантии ...