New views of crustal architecture and tectonic evolution in East Antarctica

Abstract:

East Antarctica is the least understood continent on Earth due to its sheer size, major ice sheet cover and remoteness. Coastal outcrops and glacial erratics yield cryptic clues into up to 3 billion years of East Antarctica’s tectonic evolution. These geological constraints also represent pillars to study global geodynamic linkages between East Antarctica, Australia, India, South Africa and Laurentia in the growth, assembly and dispersal of Gondwana, Rodinia and Nuna supercontinents. Due to the lack of drilling, however, our ability to project, test and augment these interpretations in the interior of the continent beneath the East Antarctic Ice Sheet remains limited.

Airborne and satellite gravity data and seismology provide key new constraints on crustal and lithosphere thickness and large-scale heterogeneity in the East Antarctic lithosphere. However, detailed imaging of the architecture of crustal domains and their boundaries relies critically on magnetic anomaly data interpretation.

Here we exploit analyses of a recent continental-scale magnetic anomaly compilation (ADMAP 2.0) augmented by our new aeromagnetic and aerogravity datasets over the Recovery and South Pole frontiers to:

1) propose a mosaic of distinct Precambrian crustal provinces that represent the building blocks of interior East Antarctica;

2) provide new geophysical constraints for different hypotheses of East-West Gondwana amalgamation along several candidate suture zones, including in particular the Shackleton suture and

3) re-assess potential paths and significance of the Kuunga suture between Greater India and East Antarctica and the so called Indo-Australo-Antarctic suture.