Geology and Geophysics

Program Manager

Antarctica represents about 9 percent of Earth's continental crust and has been in a near-polar position for more than 100 million years. It is covered by a continental ice sheet with an average thickness of 3 km. There is unequivocal evidence that for a long period after the continent arrived at its high-latitude position, extensive continental ice sheets did not exist there. The ice sheets, through their interaction with and effect on oceanic and atmospheric circulation, play a key role in modulating global climate. 

 Important problems of interest to the Geology and Geophysics program include: 

• determining the tectonic evolution of Antarctica and its relationship to the evolution of the continents from Precambrian time to the present 
• determining Antarctica's crustal structure 
• determining the effect of the dispersal of Antarctic continental fragments on the paleocirculation of the world oceans, on the evolution of life, and on global paleoclimates and present climate
• reconstructing a more detailed history of the ice sheets, identifying geological controls to ice sheet behavior, and defining geological responses to the ice sheets on regional and global scales 
• determining the evolution of sedimentary basins within the continent and along continental margins

Above: Swath bathymetric map of the Bransfield Strait, Antarctica. Showing subsea volcanic features. 

All of these problems involve the need for an improved understanding of where, when, and how Antarctica and its surrounding ocean basins were accommodated in the interplate movements inferred from studies of global plate kinematics. In short, the program encourages investigation of the relationships between the geological evolution of the Antarctic plate and paleocirculation, paleoclimate, and the evolution of high-latitude biota. A current emphasis is the West Antarctic Ice Sheet Program in conjunction with the Antarctic Glaciology Program. 

In geophysics, the continent and its environs have a central role in the geodynamic processes that have shaped the present global environment. The tectonic role of the Antarctic continent in the breakup of Gondwanaland, the close interaction of the Antarctic crust and ice sheet with their attendant effects on the planet's fluid systems, and Antarctica's present day seismically quiescent role defines the important thrusts of geophysical research in the high southern latitudes. Modern geophysical and logistical technology might focus on three broad “transect zones,” across the Weddell and Ross embayments and in the area of the Amery Ice Shelf, where prospects for broad-scale understanding of the region are highest.   

In addition to research focusing on Antarctica, the program plays a key role, along with NASA and the Smithsonian Institution, in collecting meteorites and facilitating their use in research. The Antarctic Geology and Geophysics Program supports meteorite collection through ANSMET, the Antarctic Search for Meteorites, and chairs an interagency committee that is responsible for oversight of curation and sample allocation activities for the Antarctic meteorites. NASA provides special curatorial services at the Johnson Space Center in Houston and the Smithsonian provides long term curation in the national collections. Both NASA and the Smithsonian participate in developing basic sample descriptions. Collection expeditions over the last two decades by ANSMET have resulted in more than 10,000 meteorite samples that are available for research. This constitutes about 25% of the world supply of meteorites for scientific research. Within the collection are several samples of the Moon and 5 of the 12 known Martian meteorites, including ALH84001 which is at the center of the controversy about possible evidence of microbial life on early Mars.   

Last modified: April 2004; Office of Polar Programs