Project Leader:
hemming
(sidney@ldeo.columbia.edu)
Additional External Researchers:
Martin Roy, University of Oregon
Locations: Antarctica
Description:
Antarctica occupies an area larger than the combined areas of the United States and Mexico. Nevertheless, our knowledge of its geological history is largely based on the 2% of the continent that is not covered by the extensive ice sheets. Antarctica was an important component of Mesoproterozoic and Neoproterozoic supercontinent configurations, but due to the paucity of outcrops, many important aspects of the amalgamation and break up processes, including basic aspects of the continental configurations are still ambiguous. For example, the SWEAT (Southwest U.S.-East Antarctic) connection has had an enormously important impact on research in Antarctica and beyond, and its validity has been a subject of much recent debate. Glacially eroded marine sediments offer an additional approach to outcrop studies, from which integrated information on Antarctic bedrock geology from all around the continent can be derived. (1) One aspect of the proposed work is to use a combination of petrography, bulk sediment geochemistry and radiogenic isotopes, as well as isotope chronology of individual mineral grains, to unravel crust formation ages and thermal histories of three key areas of East Antarctica (eastern Weddell Sea, Wilkes Land, Prydz Bay). Samarium-Nd isotopes and 40Ar/39Ar mineral ages from a previous sediment survey around Antarctica capture the main tectono-stratigraphic divisions and thermal events of Antarctica. A main objective of the proposed work is to constrain supercontinent configurations and break-up processes ca. 500 Ma and before. (2) Furthermore, the Antarctic continent is currently centered on the South Pole and is encircled by the Antarctic Circumpolar Current (ACC). The ACC plays a crucial role in the present-day global ocean current system, connecting the three major ocean basins and therefore permitting efficient global water mass and tracer exchange. A second aspect of the proposed work is to achieve a quantitative understanding of sediment dispersal, focusing on the Ross Sea sector, in a Holocene-Last Glacial Maximum (LGM) comparison.
EI Unit:
Lamont-Doherty Earth Observatory (LDEO)
Core Disciplines:
Earth Sciences
Collaborating Institutions:
University of Oregon
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