We are excited to invite you to the 11th seminar of the 2025 Geology and Geophysics Seminar Series, featuring Patrice Rey, a Professor of Structural Geology, Tectonics and Geodynamics in the School of Geosciences, University of Sydney. Patrice will be presenting on “A Thermo-Mechanical Framework for Proterozoic Basins“. This interesting talk will delve into how elevated thermal conditions in the Proterozoic era influenced crustal behavior, extension styles, and basin development, offering fresh insights into the formation of ancient basins.
Date: June 18, 2025
Time: 11:00 a.m. – 12:00 p.m. AEST
Location: Room 449 (Conference Room), Madsen Building (F09), School of Geosciences
or Online (Join via zoom)
We look forward to seeing you there in person or joining us online!
https://uni-sydney.zoom.us/j/84796471781?from=addon
A Thermo-Mechanical Framework for Proterozoic Basins
Abstract
Owing to the strong temperature dependence of the rheology of rocks, and the enhanced rock content in heat-producing radiogenic elements back in time, we can expect that tectonic processes in Proterozoic times may have been significantly different from those of today.
Numerical experiments show that under a warmer geotherm, and despite steady-state kinematic boundary conditions, extension leads to a bimodal tectonic history involving a transition from a long period of wide-rift extension with a low strain rate to a shorter period of narrow-rift extension with a high strain rate leading to breakup. This transition is due to the progressive cooling and strengthening of the lower crust, enabling the mechanical coupling of the brittle upper crust and the stronger upper mantle. During the wide-rift cycle, connected shallow basins are broadly distributed over a homogeneously thinned continental crust and lithosphere. In the early stage of the wide-rift cycle, decompression melting may be pervasive underneath the extending lithosphere. Translated to the real world, this suggests that some shallow Proterozoic basins may have been largely intra-continental, therefore poorly connected to the open ocean, and prone to the deposition of shales rich in organic carbon and evaporites, interlayered with volcanics.
Graphical Abstract
