Aeromagnetic and gravity data of the Central Transantarctic Mountains

Near complete coverage of the East Antarctic shield by ice hampers geological study of crustal architecture important for understanding global tectonic and climate history. Limited exposures in the central Transantarctic Mountains (CTAM), however, show that Archean and Proterozoic rocks of the shield as well as Neoproterozoic-lower Paleozoic sedimentary successions were involved in oblique convergence associated with Gondwana amalgamation. Subsequently, the area was overprinted by Jurassic magmatism and Cenozoic uplift. To extend the known geology of the region to ice-covered areas, we conducted an aeromagnetic survey flown in draped mode by helicopters over the Transantarctic Mountains and by fixed-wing aircraft over the adjacent polar plateau. We flew >32,000 line km covering an area of nearly 60,000 km2 at an average altitude of 600 m, with average line spacing 2.5 km over most areas and 1.25 km over basement rocks exposed in the Miller and Geologists ranges. Additional lines flown to true north, south and west extended preliminary coverage and tied with existing surveys. Gravity data was collected on the ground along a central transect of the helicopter survey area. From December 2003 to January 2004, the CTAM group flew a helicopter and twin-otter aeromagnetic survey and collected gravity station data on the ground in profile form. These data will be integrated with other geologic and geophysical data in order to extend the known geology of the region to ice-covered areas.