Revealing the crustal architecture of the least understood composite craton on Earth: East Antarctica

East Antarctica hosts one of the largest Precambrian cratons on Earth. Meager coastal exposures and sediment provenance studies provide glimpses into up to 3 billion years of its geological history. Extensive ice sheet cover hampers however our knowledge of crustal architecture, and consequently the geodynamic processes responsible for the growth and amalgamation of East Antarctica have remained elusive. Here we exploit recent aerogeophysical exploration efforts to help unveil the large-scale crustal architecture of East Antarctica. We focus on three sectors of East Antarctica: the Transantarctic Mountains and Wilkes Basin area; the Recovery/Dronning Maud Land area and the Gamburtsev Province. These areas provide new insights into both the margins of the so called Mawson craton and the processes that affected its interior. A 1,900 km-long linear magnetic and gravity boundary is imaged along the western flank of the Wilkes Basin and interpreted here as a crustal-scale Paleoproterozoic suture zone (ca 1.7 Ga) that inverted a former passive margin. Two ribbon-like Archean and Paleoproterozic microcontinents were assembled during this stage, resembling modes of amalgamation of Paleoproterozoic microcontinental ribbons in Australia. The proposed Proterozoic sutures and microcontinent boundaries also influenced Neoproterozoic rifted margin and early Cambrian back-arc basins in the Wilkes Basin/Transantarctic Mountains region. In the Recovery/Dronning Maud Land region our new potential field compilations reveal a wide tract of anastomising crustal-scale shear zones, likely of Pan-African age that flank and variably deform the margins of several distinct Archean, Paleo-Mesoproterozoic and Grenvillian age crustal blocks. In the Gamburtsev Province new magnetic and gravity models provide insights into the Gamburtsev Suture (Ferraccioli et al., 2011, Nature) that separates the Ruker Province from an inferred Grenvillian-age orogenic Gamburtsev Province with remarkably thick crust (up to 60 km thick) and thick lithosphere (over 200 km thick). We suggest that a recently inferred Tonian-age accretionary belt identified in the Sor Rondane region continues further inland in the Gamburtsev Province and was likely also reactivated during Pan-African age transpression linked to Gondwana assembly

New Views of East Antarctica- from Columbia to Gondwana

East Antarctica is a keystone in the Gondwana, Rodinia and the Columbia supercontinents. Recent aerogeophysical research, augmented by satellite magnetic, gravity and seismological data is unveiling the crustal architecture of the continent. This is helping comprehend the impact of supercontinental processes such as subduction, accretion, rifting and intraplate tectonics on its evolution. A mosaic of Precambrian basement provinces is apparent in interior East Antarctica (Ferraccioli et al., 2011, Nature). A major suture separates the Archean-Neoproterozoic Ruker Province from an inferred Grenvillian-age orogenic Gamburtsev Province with remarkably thick crust (up to 60 km thick) and thick lithosphere (over 200 km thick). The age of the suturing and its linkages with supercontinental assembly is debated with both Rodinia and Gondwana candidates being proposed. Further east, magnetic highs delineate a Paleo to Mesoproterozoic Nimrod-South Pole igneous province (Goodge and Finn, 2010 JGR) that flanks a composite Mawson Continent- including the Gawler Craton of South Australia (Aitken et al., 2014 GRL). An over 1,900 km long magnetic and gravity lineament is imaged along the western flank of the Wilkes Subglacial Basin and is interpreted here as a major Paleoproterozoic suture zone linked to the collision of Laurentia and East Antarctica within Columbia. The proposed suture played a pivotal role helping localise Neoproterozoic Rodinia rifted margin evolution and forming a backstop for the Ross-Delamerian cycle of Gondwana amalgamation. Aeromagnetic and gravity imaging help determine the extent of a Keweenawan-age (ca 1.1 Ga) large igneous province in the Coats Land Block -isotopically tied with the Mid-Continent Rift System of Laurentia (Loewy et al., 2011 Geology). Imprints of Grenvillian magmatic arc accretion link together the Namaqua-Natal and Maud belts in South Africa and Dronning Maud Land within Rodinia. The aeromagnetically distinct Southeast Dronning Maud Land province (Mieth and Jokat, 2014 GR) may represent a separate 1000-900 Ma Oceanic Arc Superterrane (Jacobs et al., 2015 Prec. Res.). New geophysical views of the Shackleton Range suture lend weight to more complex collisional and indentation tectonic models for the Pan-African age assembly of Gondwan