Glaciohydraulic supercooling: a freeze-on mechanism to create stratified, debris-rich basal ice: II. Theory

Simple theory supports field observations (Lawson and others, 1998) that su bglacial water flow out of overdeepenings can cause; accretion of layered, debris-bearing ice to the bases of glaciers. The large meltwater flux into a temperate glacier at the onset of summer melting can cause rapid water fl ow through expanded basal cavities or other flow paths. If that Row ascends a sufficiently steep slope out of an overdeepening, the water will superco ol as the pressure-melting point rises, and basal-ice accretion will occur. Diurnal, occasional or annual fluctuations in water discharge will cause v ariations in accretion rate, debris content of accreted ice or subsequent d iagenesis, producing layers. Under appropriate conditions, net accretion of debris-bearing basal ice will allow debris fluxes that are significant in the glacier sediment budget.