Evolution of lateral tectonophysical stresses in the spherical shell convection with an immobile supercontinent
Year: 2025
Type: article
Abstract: We investigate the evolution of horizontal stress fields after implementing a supercontinent into spherical mantle model with the temperature- and pressure-dependent rheology and phase transitions, while assuming that the mantle is heated from the base and from within. Before implementation of the supercontinent, the overlithostatic horizontal stresses in the main part of upper mantle are in the range of ±15 MPa, while the horizontal stresses along subduction zones and around mantle plumes are significantly larger (±25 MPa and more). The supercontinent is modeled as an undeformable, highly viscous, immobile lid with respect to the ambient mantle and it is abruptly imposed on well-developed mantle convection. After implementation of the supercontinent, the mantle flow is rearranged and a group of upwelling mantle plumes is formed under the supercontinent and their hot heads increase in size due to the heat-insulating effect of the supercontinent, while quasi-linear subduction zones increase in the oceanic region. As a result, the average temperature of the area under the supercontinent rises over time and becomes higher than the average temperature of the suboceanic area, where cold descending mantle flows intensify. Аt the depth of about 300 km under the supercontinent the temperature of the subcontinental mantle rises on average by 60 K. Formed under the supercontinent, mantle plumes dramatically change the stress pattern in the supercontinental area producing tensional stresses in the supercontinent and overlithostatic compressive horizontal stresses in the subcontinent mantle. Tensile overlithostatic horizontal stresses inside the supercontinent are about 20-30 MPa, whereas beneath a supercontinent we recognize the overlithostatic compressive horizontal stresses in the subcontinent mantle of about 25-60 МРа.
Source: Frontiers in Earth Science
Institution: Hong Kong Polytechnic University
Language: English
Subfield: Geophysics
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $3,801
OpenAlex ID: W4409957785