GM3.1/GD3.8/TS3.6Response of the Earth’s surface to climate, tectonics and long-wavelength low-amplitude forcing (co-organized)
|Convener: Pierre Valla | Co-Conveners: Romain Delunel , Carole Petit , Jean Braun|
Earth Surface Dynamics (i.e. the processes shaping the Earth’s surface) is identified as one of the most promising research fields in the Earth Sciences. This field has strong societal impacts because changing environmental conditions modify the equilibrium of the complex climate-erosion system, and because slope stability and sediment supply are key factors for hazard assessment, especially in a mountainous environment. But beyond this, our knowledge of erosional processes and sediment fluxes, as a function of tectonics and climate, is fundamental to apprehend the Earth System, as it modifies the old paradigm of how we comprehend mountain evolution. Understanding and quantifying the connections between tectonics, climate and erosion in shaping the Earth’s surface, including the likely interaction with human perturbation, is hence of prime importance.
Plate tectonics is commonly regarded as the main driver of surface uplift/subsidence of continental areas and, consequently, as the main source of surface relief. We all assume that topographic highs are the product of crustal thickening resulting from continental collision or magmatic underplaying, and that basin subsidence is driven by crustal stretching and lithospheric cooling following extension. There are, however, many parts of the geological record that cannot be explained by plate tectonics alone, including the rapid uplift and erosion of large continental areas (plateaux or intra-cratonic basins) that are likely to be the result of dynamic topography generated by the viscous stresses caused by mantle convection at the base of the lithosphere. It has also been recently proposed that large-scale topographic relief can result from gradients in isostatically-driven rebound of previously thickened or stretched continental areas caused by surface rock density variations.
This session aims to present innovative studies that primarily quantify relief, relief change, altitude and erosion over different temporal and spatial scales in relation with climate and / or tectonics. Emphasis will be put on modern tools and original viewpoints. This includes (but is not limited to) surface-process modelling, low-temperature thermochronology, geochemistry, cosmogenic radionuclide dating or other innovative tools. We also invite contributions from studies on how the Earth’s surface has reacted to non-tectonic stimulations, based on observational or modeling studies, with the scope of better understanding the geomorphic response to long-wavelength, low-amplitude surface relief creation and the nature and characteristics of the driving mechanism (the scale and timing of dynamic topography, for example).