Deformation and exhumation in thick continental crusts induced by valley incision of elevated plateaux
Year: 2025
Type: article
Abstract: . Surface processes such as erosion and sedimentation play a critical role in crustal deformation, particularly in actively deforming orogenic belts. While these processes have been extensively studied in large-scale erosive and tectonically active regions, the specific effects of valley incision on crustal deformation, especially in tectonically inactive regions, remain poorly understood. In this study, we hypothesize that crustal deformation induced by valley incision is primarily governed by three parameters: incision velocity, crustal thickness, and the elevation difference between the plateau and the valley base level. Using two-dimensional thermo-mechanical models, we investigate the influence of valley incision on crustal deformation and exhumation by varying these parameters. Our results show that valley incision alone can induce significant crustal deformation, associated with lateral viscous flow in the lower crust leading to near-vertical channel flow and extensional brittle deformation in the upper crust below the valley. This deformation leads to lower crust exhumation, within a 10 Myr timeframe, if crustal thickness is greater than 50 km, the initial plateau elevation is greater or equal to 2 km, and the long-term effective erosion rate exceeds 0.5 mm.yr-1. Furthermore, while the onset of lower crust exhumation is primarily controlled by the initial plateau elevation, the total amount of exhumed lower crust after 10 Myr strongly increases with the initial thickness of the lower crust which favors viscous flow. We also show that despite the simplified tectonic context of our models, the first-order results align well with observations from natural systems. These findings offer new insights into the coupling between surface processes and deep crustal dynamics, highlighting the potential for valley incision to drive substantial crustal deformation and promote lower crustal exhumation.
Source: Solid Earth
Language: English
Subfield: Geology
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,811
OpenAlex ID: W4416128458