3D flexural modeling of the lithosphere under the action of differential denudation on the continental margin

• Grant number: 20/10022-5
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: October 01, 2020
• End date: July 31, 2021
• Field of knowledge: Physical Sciences and Mathematics - Geosciences - Geophysics
• Principal Investigator: Victor Sacek
• Grantee: Felipe Baiadori da Silva
• Host Institution: Instituto de Astronomia, Geofísica e Ciências Atmosféricas (IAG). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

Surface processes of erosion and sedimentation result in load redistribution on the Earth's crust, inducing an isostatic and flexural response of the lithosphere, and the wavelength of this response depends on how rigid the lithospheric plate is. Therefore, the combined study of the denudation history of the continents and the isostatic and flexural response of the lithosphere can contribute to provide important information about the physical properties of the lithospheric crust and mantle in geological time. The objective of the present project is to estimate the rigidity of the lithosphere through numerical models that simulate the flexure of the lithosphere, having stratigraphic and topographic data as constraints. In the present work, the lithosphere is modelled as an elastic plate superimposed on a fluid medium in geological time, representing the asthenosphere. The numerical solution of the flexure equation is implemented using the finite difference method. Additionally, the amount of material eroded is estimated through the numerical resolution of the diffusion equation over the current topography, assuming linear diffusion, in order to estimate the volume of topographic load on the lithospheric plate. The proposed model is applied to the study the Tucano basin (northeastern Brazil), together with geological constraints provided by outcrop descriptions in the basin, with the purpose of estimating the effective elastic thickness of the lithosphere in this region during the post-rift phase of the basin.