High-resolution Aeromagnetic Imaging of the Lanterman Range, North Victoria Land

The Lanterman Range covers the boundary between the Wilson Terrane and Bowers Terrane, i.e. the two western tectonometamorphic units of the Ross-orogenic basement of North Victoria Land, Antarctica. This boundary is formed by a distinct belt of highly deformed mafic and ultramafic rocks with UHP relicts. It is interpreted as the trace of a former suture zone that formed during continuous accretion at the Palaeo-Pacific active continental margin of East Gondwana in the Early Paleozoic. We report on high-resolution magnetic anomaly data over the Lanterman Range. Preliminary results show two distinct and nearly parallel magnetic lineaments. These magnetic lineaments follow the main strike of the Wilson-Bowers terrane boundary. The western of these lineaments correlates with the boundary zone itself. The eastern lineament cannot be attributed to any exposed rocks so far, which show only rather low magnetic susceptibility values. Similar paralleling magnetic structures occur further to the southeast, where they are apparently offset by a possibly post-Jurassic WNW-ESE oriented left-lateral strike-slip zone. We tentatively propose that the origin of the eastern lineament is due to remnants of the Palaeo-Pacific subducted slab hidden under the boundary zone of the Bowers Terrane and the easterly dominantly turbiditic Robertson Bay Terrane. The western may represent remnants of a closed back-arc basin intermittent between the Wilson and Bowers terranes.