Alpine glacial topography and the rate of rock column uplift: a global perspective

The present study investigates the influence of alpine glacial erosion on the morphology and relief distribution of mountain regions associated with varying rock column uplift rates. We take a global approach and analyse the surface area distribution of all mountain regions affected by glacial erosion between latitudes 60°S and 60°N.Most surface area in glaciated mountain ranges is concentrated below the modern snowline as predicted by the glacial buzzsaw hypothesis. Above the modern snowline the analysed mountain regions all exhibit an exponential decay of surface area with height. On the basis of this decay, the analysed mountain regions fall within three distinct groups primarily reflecting variations in average values of rock column uplift rates. Mountain ranges affected by rapid rock column uplift display high above-snowline relief and large decay lengths, whereas inactive orogens have little relief above the modern snowline. We find a surprisingly simple relation between hypsometry above the local snowline and regional tectonic activity.