Tuesday, 28 August 2007 - 3:40 PM
2.P2.C-1
Pieces of Laurentia in East Antarctica
John W. Goodge1, Devon M. Brecke1, C. Mark Fanning2, Jeff D. Vervoort3, Ian S. Williams2, and Paul Myrow4. (1) Geological Sciences, University of Minnesota - Duluth, 229 Heller Hall, 1114 Kirby Drive, Duluth, MN 55812, (2) Research School of Earth Sciences, Australian National University, Canberra, ACT 0200, Australia, (3) School of Earth and Environmental Sciences, Washington State University, Pullman, WA 99164, (4) Department of Geology, Colorado College, Colorado Springs, CO 80903
Geologic, age and isotopic data from the central Transantarctic Mountains provide a unique test of the Rodinia fit between East Antarctica and Laurentia. Evidence supporting a SWEAT-type fit includes: (1) similar Nd-isotope crustal age provinces; (2) similarity of ~1.7 Ga crustal events; (3) provenance link between ~1.4 Ga detrital zircons in Antarctic rift-margin strata and Mesoproterozoic A-type granites in Laurentia; (4) associated 1.8-1.6 Ga detrital zircons in these strata; and (5) similarity in ages of rift-margin formation. New isotopic and age data include: (6) ~1.4 Ga Antarctic-margin detrital zircons have Hf-isotopic compositions matching the A-type Laurentian granites; and (7) a newly discovered A-type rapakivi granite boulder in glacial till at Nimrod Glacier has a U-Pb zircon age of ~1440 Ma, indicating the presence of Mesoproterozoic granites beneath the East Antarctic ice sheet. We suggest that these detrital-mineral and rock clasts represent distinctive pieces of Laurentia in East Antarctica.