Variability of the Antarctic mantle, crust and sub-ice topography shapes ice sheet and Earth system evolution from beneath

Solid Earth structure, often overlooked as a component of Earth system interactions, can be an important system component as the battle between gravity and heat plays out in the mantle. The heterogeneity of the crust, and changing topography and character of the sub-ice region further intensifies or adds fine detail to the variability of influence from beneath. This is the dynamic foundation for ice sheets and other Earth system components.

 

In this presentation, aspects of solid Earth structure that impact the ice sheet and other Earth system components are reviewed and their past, present and future influence on the evolution of the polar regions, especially Antarctica, are considered. On long time-scales, plate tectonics controls the form of ocean basins and deepwater pathways, and hence the development of major ocean currents. On shorter time-scales, solid Earth structure has a significant influence on continental water flow, and heat flow, which both contribute to shaping ice sheets from beneath.

 

Geophysical approaches illuminate hidden parts of our planet, and nowhere is this more significant than the polar regions where ice sheets add a further concealing layer. Our concepts of Earth structure in the polar regions are thus formed in terms of physical properties such as density, seismic wavespeed and electrical conductivity together with constraints from plate tectonic history and sparse geological and geochronological information.

 

Looking forward, Earth-ice interactions are important boundary conditions for initiatives that aim to improve the prediction of ice sheet response to changes in atmospheric and ocean forcing. Our challenge is to capture the variability and deep Earth structure and the diversity of sub-ice processes at sufficient detail, and with sufficient rigour in multivariate and computational approaches, to truly represent the interplay between the solid Earth and the systems it supports.