Evolution of the Gamburtsev Province from arc accretion and collision to intraplate tectonics

The Gamburtsev Subglacial Mountains are underlain by 50-60 km thick crust formed during the assembly of a mosaic of distinct Precambrian provinces in East Antarctica. Our enhanced magnetic and gravity images, depth to magnetic and gravity sources and 2D models help unveil the crustal architecture and the tectonic evolution of the Gamburtsev Province (GP). Major fault systems can now be recognised as segmenting the GP into the Northern, Central and Southern domains. When combined with independent sediment provenance constraints we interpret our results as revealing thrusted arc and back arc terranes of inferred 1.3-1.0 Ga age in the Northern and Central domains of the GP. Dense lower crust beneath these domains may also reflect widespread magmatic underplating.

By analysing these data together with the ADMAP 2.0 Antarctic magnetic anomaly compilation (Golynsky et al., 2018, GRL) we propose that these arc terranes are related to the Tonian Oceanic Arc Superterrane in the interior of Dronning Maud Land (Ruppel et al., 2018, Prec. Res) and likely reflect more widespread accretion of Mesoproterozoic to Neoproterozoic juvenile arc-related crust. These arc terranes are distinct from the Archean Ruker Craton to the north and the South Pole province to the south, an inferred Mesoproterozoic igneous province (1.6-1.4 Ga?) formed within the Mawson Craton.

The age of the collision of these arc terranes against Greater India and the Mawson Craton is debated with ca 1 Ga (e.g. Ferraccioli et al., 2011, Nature) and Pan-African ages (ca 550 Ma) both being previously inferred (e.g. An et al., 2015, JGR). By interpreting the ADMAP 2.0 compilation and satellite gravity gradient data from GOCE we therefore discuss potential relationships between the Gamburtsev Suture in the GP and the Kuunga and Shackleton sutures. We also examine alternative models suggesting that the GP was located in a more intraplate setting after ca 600 Ma, similar to the Petermann Orogeny in Australia (Veevers, 2018, ESR).