Fig. 5: 3D resistivity model and magmatic processes.

a 3D visualization facing Mercator north of the 5 (red) and 10 (yellow) Ωm resistivity contours from the 3D finite element inversion. Gray band extending to 15 km depth is the conjectured Erebus fault zone (EFZ) within which the crustal Erebus conductor and possibly the minor Terra Nova conductor lie. Also shown is the projection of the deepest offset portion of the Discovery graben fault zone¹⁴; b schematic depiction of magmatic processes conjectured to be occurring nominally in the core zone of the MT low resistivity, generally following recent petrological results^2,4. Nominally, two channels of upward flow concentration from a deep-middle crustal throttle zone exemplify episodic breakthrough of CO₂ and entrained magma. The convective melt zone drawn in the 4–8 km depth range¹¹ is compatible with the inversion cross-section of Fig. 3b. Spatially continuous upflow of CO₂-dominated magma is in contrast to depth-limited magma zones of H₂O arc volcanoes.