The effect of valley confluence and bedrock geology upon the location and depth of glacial overdeepenings

Overdeepenings are erosional landforms, cut by glaciers into bedrock in basins and valleys. Overdeepening is the glaciological geomorphological process that produces these landforms. The overdeepening important because it has potential to influence response of ice masses climatic changes. In this paper, we analyze topographic bathymetric digital elevation models examine several hundred glacial overdeepenings Labrador, Canada. We investigate controls upon location depth overdeepenings. Our analyses show correlate strongly with confluences valleys and, importantly, correlation strongest where confluence geometry requires speed-up ice-flow due change valley cross-sectional area. Further, find magnitude correlates only for situated or near major geological fault-zones. findings therefore support hypothesis can be initiated an increase velocity. conclude most efficacious fractured enables efficient quarrying. summary, primary control arises from speeding up at locations, controlled rock mass strength. These relevant landscape evolution modelling may used model testing.