A geophysically constrained crustal element map of East Antarctica between Enderby Land and Princess Elizabeth Land

Abstract

East Antarctica along with Greater India played a vital role in the accretion and breakup of the Indo-Antarctic landmasses during the supercontinents Nuna, Rodinia and Gondwana. Without geophysical potential field methods, interpreting the architecture of the ice-covered geological provinces of Antarctica is impossible. We present here a crustal element map of East Antarctica between Enderby Land and Princess Elizabeth Land (Indo-Antarctica tectonic element) using aerogeophysical data interpretation. The data reveal distinct anastomosing geophysical provinces that correlate with sparse geological data. Our crustal element map shows the Oygarden Province and the Northern and Southern Rayner provinces are arcuate belts that wrap around the Archean Napier Province. These provinces represent the remnants of an accretionary tectonic margin, which evolved between ca 1300 Ma and 900 Ma. The arcuate geometry of these Meso- to Neoproterozoic provinces formed during the collision with the Napier Province, which represents a microcontinent. This collision triggered widespread extension and ultra-high temperature metamorphism in the Northern and Southern Rayner provinces. The southernmost provinces include the Fisher Province, Lambert Province and a transition zone. The provinces are truncated by a suture zone with the Archean Ruker Province, following north-dipping subduction during the Meso- to Neoproterozoic. Our interpretation provides a template upon which to correlate geological provinces with the terranes on the conjugate eastern Indian margin. KEY POINTS An aeromagnetic interpretation is given for Enderby Land and Princess Elizabeth Land of East Antarctica. Napier Province is a microcontinent that collided with the Rayner Province during a ca 1000 Ma orogenic event. A new interpretation of potential field data suggests anastomosing provinces accreted as part of a collisional event. New structures/piercing points are identified at the Mawson Coast and in Kemp Land.