Crust and Uppermost Mantle Heterogeneity in East Antarctica, and Potential Impacts on Earth-ice Interactions.

The ancient landmass of East Antarctica was assembled through multiple cycles of tectonic supercontinent assembly and breakup. Sparse geological exposures around the periphery of the continent, set in the context of plate reconstructions, provide clues to the nature of those assembled lithospheric domains and their boundaries. However, many boundary locations are obscured by ice, and cryptic domains (i.e. with no exposure) are likely in the East Antarctic interior. 

 

This presentation takes a step towards better constraints on the architecture and character of the crust and upper mantle components of the lithosphere. The study makes use of seismic and multivariate geophysical inputs, introducing new data from recent field campaigns such as the CAD (Casey-Davis) deployment with co-located seismic and GNSS instruments.

 

We place new constraints on parameters such as bulk geological composition, crustal thickness and Moho character to enable the refinement of previous low-resolution 3D models of East Antarctica. We outline how the spatial heterogeneity of these properties might (a) shape the ice sheet from below and (b) impact the dynamics of the Earth’s response to ice mass change.

 

Metrics calculated to appraise the spatial variation in uncertainty of the above properties show that significant knowledge gaps remain.  Targeted data collection might be achieved through collaboration between National Antarctic Programs, newly invigorated by making use of independent logistics providers. We welcome discussions that might further improve solid Earth datasets to inform Earth-ice interactions in East Antarctica.