Sedimentary processes may cause fluctuations of tidewater glaciers

Abstract

A temperate glacier ending in water advances by depositing a moraine shoal, which “dams” tidewater calving, and then recycling this shoal in conveyor-belt fashion. A simple model suggests that conveyor-belt recycling of the shoal must continue until calving stops and all ice flux is removed by surface ablation, or until the glacier retreats rapidly from the shoal; retreat can occur without external forcing if the glacier advances into deepening water and if sediment recycling is rapid compared to supply of new sediment to the moraine shoal.