Recent Aeromagnetic Surveys Image Cenozoic Magmatism of the Transantarctic Mountains and Reveal Faults Along the Eastern Margin of the Wilkes Subglacial Basin

We present results from two recent aeromagnetic surveys over two major tectonic elements of the Northern Victoria Land (NVL) sector of East Antarctica: the Transantarctic Mountains (TAM), forming the uplifted flank of the West Antarctic Rift System (WARS), and the Wilkes Subglacial Basin (WSB), in the hinterland of the TAM. The MAGANTER survey was performed during the 2001/02 Italian Antarctic campaign to investigate Cenozoic magmatic patterns over the Admiralty Mountains. Cenozoic magmatic rocks of the TAM provide a unique window on the tectonic and magmatic processes of the WARS. Previous aeromagnetic investigations further south in NVL have delineated Cenozoic volcanic and intrusive complexes assigned to the McMurdo Volcanic Group and Meander Intrusives respectively. Our new aeromagnetic anomaly maps show that the Meander Intrusives are restricted to the coastal region between Malta Plateau and the Daniell Peninsula and trend at high angle to the major Cenozoic strike-slip faults of the region. However, the McMurdo Volcanic Group rocks extend further inland, and may delineate a volcano-tectonic rift zone parallel to offshore rift basins. The newly identified spatial distribution of Cenozoic magmatic rocks may require revisions to recent tectonic models for the region. The WIBEM survey (2003/04) focused on the eastern margin of the enigmatic Wilkes Subglacial Basin. New aeromagnetic maps image subglacial faults systems along the eastern margin of the WSB, which link previously proposed fault zones over Oates Land with those along the Ross Sea Coast. Specifically they reveal a connection between the Matusevich Frature Zone and the Priestley Fault. The new aeromagnetic evidence for structural control on the eastern margin of the WSB contrasts with a purely flexural origin for this part of the WSB, proposed from some previous gravity models.