Crustal architecture of the Transantarctic Mountains between the Scott and Reedy Glacier region and South Pole from aerogeophysical data

Aerogeophysical data collected in transects between the South Pole and West Antarctica, crossing the Transantarctic Mountains at the 150 degrees W meridian, are used to constrain the sub-ice topography, the sub-ice geology and the inland structure of the Transantarctic Mountains. Forward modeling of gravity data suggests slight crustal thickening of 5 km beneath the mountain front indicating partial isostatic compensation by thickened crust. New magnetic data help characterize the sub-ice geology inland of the Transantarctic Mountains with the observed magnetic anomaly field dominated by Granite Harbour Intrusives, similar to the magnetic field in Victoria Land. However, the typical pattern of anomalies caused by Jurassic tholeiitic magmatism elsewhere along the Transantarctic Mountains is not observed, nor is the mesa topography that is often associated with the Ferrar Dolerite. Together, these observations rule out the widespread presence of Ferrar Dolerite sills within the survey area. A pronounced magnetic lineament, herein named the South Pole Lineament, parallel to the 0 degrees/180 degrees longitudinal meridian, beneath the South Pole defines a previously unknown tectonic trend of the East Antarctic craton. The lineament suggests the presence of a lithospheric-scale structure beneath South Pole, projecting into a fault mapped from ice-penetrating radar data and extending to Shackleton Glacier, the site of a major geological boundary across the Transantarctic Mountains. Potentially, the lineament is the expression of the edge of the undeformed craton, an inherited structure created during assembly or breakup of Rodinia and Gondwana supercontinents; or an intracontinental transform. (c) 2006 Elsevier B.V. All rights reserved.