Stress field evolution in the lithosphere: a numerical approach

• Grant number: 17/10554-4
• Support type: Scholarships in Brazil - Doctorate
• Effective date (Start): August 01, 2017
• Effective date (End): March 31, 2020
• Field of knowledge: Physical Sciences and Mathematics - Geosciences
• Cooperation agreement: Coordination of Improvement of Higher Education Personnel (CAPES)
• Principal Investigator: Victor Sacek
• Grantee: Rafael Monteiro da Silva
• Home Institution: Instituto de Astronomia, Geofísica e Ciências Atmosféricas (IAG). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 13/24215-6 - Pantanal-Chaco-Paraná basins (PCPB): crust and upper mantle seismic structure and evolution, AP.TEM

Abstract

The stress field in the lithosphere acts controlling the dynamics of the lithosphere, whose action results either in abrupt crustal deformations, such as earthquakes or in long-term, such as continental rifting. In addition, the knowledge of the lithosphere rheology and its dynamic behavior is strictly related to the stress field due to the relationship between stress and deformation. Despite the widely use of numerical modelling to investigate rifting processes and continental lithosphere break-up and associated geodynamic processes, lesser attention was directed to the onshore region of the margin and its post-rift evolution. This project aim to develop a visco-elasto-plastic numerical model to explore the stress field of lithosphere and its temporal evolution. The numerical implementation will use a previous, two-dimensional, viscoelastic rheology model as a starting basis. This model will be expanded to include three-dimensional geometry, using hexahedral elements and plastic deformation to simulate the brittle deformation of the rocks. The model will also be coupled with a surface processes model that simulate erosion and sediment deposition. The developed model will be applied in the two evolutionary contexts of the South American plate: (1) the southeastern margin of Brazil, with a special focus on the Continental Rift of Southeastern Brazil; (2) sedimentary basins of Pantanal, Chaco and Paraná. The aim of this project is to understand the mechanisms involved in the evolution of these regions during and after the opening of the South Atlantic. In this context, the project will explore the role of three-dimensional geometry of the margin and preexisting structures within the continent, the lithosphere rheology and intraplate forces, originated at the edges of the plates, in the stress field of lithosphere and their implications for the formation and evolution of hinterland basins. (AU)