Dept. of Geophysics Colloquium: Earthcasting fast-evolving landscapes and high-order sediment transport dynamics

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Abstract:

Earth's landscapes are shaped by competition between tectonic plates that push bedrock upward and river networks that remove mass. Transport of countless rock fragments is a fundamental aspect of this action, resonating with many other near-surface processes across the hydrosphere, biosphere, and geosphere. Identifying how efficiently rock fragments are transported away, considering their properties and ecohydrological feedbacks during weather events, has remained a persistent scientific challenge since the dawn of computational geomorphology. With recent advances in terrain remote sensing and analysis techniques, hydroclimate observations/models, and computational methods for describing dynamic topography, a research frontier is emerging, paving the way for a promising new era in the science of surface processes and topographic forms.

The seminar first presents a new application of a theory for heterogeneous sediment transport in mountainous gravel-bed rivers. A set of numerical experiments discovered process-form relations that emerge from sediment grains' lithological heterogeneity. Then, the talk will present a first-of-its-kind Earthcasting approach that integrates high-resolution event-scale rainfall forcing into a Holocene-scale landscape evolution research framework. Within that timescale, the importance of the interaction between soil grains and ecohydrological processes in shaping fast-evolving landforms is highlighted. Lastly, paleo-rainfall regimes capable of triggering erosion-deposition cycles and possible future transitions to a unique climate-erosion state by the 21st century will be demonstrated.

The findings have the potential to shift paradigms in the interpretation of sediment records and landscape forms. The newly developed methodologies enable unprecedented quantification of surface processes with respect to material properties and climate forcings, which open opportunities toward a transformational understanding of landscape evolution.

Event Organizer: Dr. Lior Rubanenko