Fig. 1

Geodynamic and tectonic map of the Tasman Gateway and northern Victoria Land. (A) Morpho-bathymetric map of the seafloor around the Macquarie Triple Junction, which marks the point where the Australian Plate, Pacific Plate and Antarctic Plate interact. The red lines are the plate boundaries between the Australian, Antarctic and Pacific plates; the white lines are the fracture zones that offset the segments of the mid-ocean ridge. In particular, the major dextral NW-SE Balleny, Tasman and George V fracture zones between the Australian and Antarctic plates are highlighted. The black dashed rectangle indicates the location of northern Victoria Land (NVL). The DEM was made using GMRT, version 4.3.0 (www.gmrt.org), and the software GeoMapApp, Version 3.7.4 (www.geomapapp.org; CC by Ryan et al.²²). Abbreviations: GVL, George V Land; LTZ, leaky transform zone; MBL, Marie Byrd Land; QML, Queen Mary Land; TA, Terre Adélie; TAM, Transantarctic Mountains; WL, Wilkes Land. (B) Tectonic sketch map of NVL and its offshore area, which includes the Adare Basin and the Adare Trough (modified and redrawn after^3,6,23). The location of the main Neogene onshore volcanic fields (orange zones) of NVL (modified after Smellie and Rocchi⁹) and volcanism in the Adare Basin and Adare Trough (red circles and bodies) (modified after Granot et al.⁶) is also indicated. The volcanic fields forming the Hallet Volcanic Province are indicated. These features are superposed onto the IBSCO (International Bathymetric Chart of the Southern Ocean²⁴) morpho-bathymetry and topography of NVL. The black dashed rectangle is the location of the area investigated by the BOOST Project. Inset: Location of Figure B on the Antarctic continent. It is located in the northernmost part of the Transantarctic Mountains, which separate West and East Antarctica.