Research Objectives:
The East Antarctic Shield is one of Earth's oldest and largest cratonic assemblies. Interest in the evolution of the shield has been rekindled over the past decade by tectonic models linking East Antarctica with other Precambrian crustal elements in the Rodinia and Gondwanaland supercontinents. It has been postulated that the Pacific margin of East Antarctica was rifted from Laurentia during the late Neoproterozoic breakup of Rodinia; it then developed as an active plate boundary during the subsequent amalgamation of Gondwanaland. A better understanding of the geological evolution of the shield is therefore critical for studying Precambrian crustal evolution in general, as well as resource distribution, biosphere evolution, and glacial and climate history during later periods. Because of nearly complete coverage by the polar continental-size ice capsheets, however, Antarctica remains the single most geologically unexplored continent. Also, little is known about the composition and structure of the shield’s interior.
Therefore, we will conduct an airborne magnetic survey (coupled with ground-based gravity measurements) across an important window into the shield where it is exposed in the Nimrod Glacier area of the central Transantarctic Mountains. Specific goals are to
+ Characterize the magnetic and gravity signature of the east antarctic crustal basement exposed at the Ross margin,
+ Extend magnetic data westward along a corridor across the polar ice capeast antarctic ice sheet to image the crust in ice-covered areas,
+ Obtain magnetic data over the Ross Orogen to image the ice-covered boundary between + basement and supracrustal rocks, and
+ Use the shape, trends, wavelengths, and amplitudes of magnetic anomalies to define magnetic domains in the shield.
Our survey (to be done in collaboration with German colleagues) will, for the first time, use geophysical methods to characterize the shield terrain in this sector. This baseline over the exposed shield will allow for a better interpretation of geophysical patterns in other ice-covered regions and can be used to target future investigations. Once the survey is done, we will then perform data reduction, interpretation, and geological correlation.
This research will lead to new basic knowledge about the antarctic continent, which in turn may help with applied research in other fields such as the glacial history of Antarctica.
