A MPG/SGT seminar presentation by Sam Kodama from UC Santa Cruz.
Title:
The influence of glacial isostatic adjustment on landscape evolution across the last glacial cycle
Abstract:
Surface processes govern the evolution of landscapes and are often sensitive to changes in topography and slope. Over the Pleistocene glacial cycles, changes in the topography and slope of mid-to-high latitude landscapes were predominately modulated by glacial isostatic adjustment, the solid-Earth deformation associated with the growth and retreat of ice sheets. These changes in slope can affect rivers’ abilities to erode and deposit sediment and therefore drive landscape evolution. Here I explore the role of glacial isostatic adjustment in the evolution of Northern Hemisphere rivers across a range of spatial and temporal scales. First, I demonstrate how changes in slope can impact the lateral erosion of the Red River (North Dakota, USA), which began flowing ~8.5 ka, and has experience continuous, non-uniform loss of slope ever since due to isostatic rebound. This non-uniform loss of slope differentially decreased Red River meander rates and left a geomorphic signal in the floodplain that is visible today. Next, I create a framework for identifying periods of time and geographic regions where we can expect glacial isostatic adjustment-induced slope change to act as the primary forcing for sediment transport of North American rivers across the last glacial cycle and therefore dictating when are where rivers deposit or erode sediment. Together, this research shows how glacial isostatic adjustment-induced slope change can impact landscape evolution from the continental to meander bend scale.
