Magma degassing during subglacial eruptions and its use to reconstruct palaeo-ice thicknesses

In this paper we lay out a number of criteria that must be satisfied for degassing to potentially record palaeo-ice thicknesses, using a variety of new datasets and calculations to highlight existing problems with the technique. These include uncertainties about volatile solubilities, non-equilibrium degassing, sample heterogeneity, hydration, post-quenching movement and whether subglacial pressures deviated significantly from glaciostatic. We propose new strategies for improvement of the technique and discuss how magmatic volatiles may control the style of subglacial eruptions.