Onset of glacier tables

TL;DR

This study models the formation of glacier tables, revealing how cap size and thermal properties influence whether they stand or sink, and identifies key factors controlling their onset.

Contribution

It introduces a one-dimensional conduction model that predicts the formation threshold of glacier tables based on thermal and geometric parameters.

Findings

The model captures the transition between standing and sinking regimes.

A dimensionless number controls the onset of glacier table formation.

Thermal conductivity and cap size are critical factors.

Abstract

A glacier table consists of a rock supported by a slender column of ice and form naturally on glaciers. We investigate the onset of their formation at a smaller scale in a controlled environment. Depending on the size and thermal conductivity of a cap, it can either form of a table standing on an ice foot, or sink into the ice block. A one-dimension conduction model shows that the differential ice melting is controlled by a competition between two effects: a geometrical amplification, and a heat flux reduction due to the higher temperature of the cap as compared to the ice. Our model captures the transition between the two regimes and identifies a dimensionless number which controls the onset of glacier tables formation.