Tuesday, 28 August 2007 - 11:10 AM
2.A.C-4
Constraints from detrital zircon geochronology on the early deformation of the Ross orogen, Transantarctic Mountains, Antarctica
Edmund Stump, School of Earth and space Exploration, Arizona State University, Tempe, AZ 85287, George Gehrels, Department of Geosciences, University of Arizona, Tucson, AZ 85721, Franco Talarico, Dipartimento di Scienze della Terra, University of Siena, via Laterina 8, Siena, Italy, and Rodolfo Carosi, Dipartimento di Scienze della Terra, Univarsity of Pisa, via S. Maria, Pisa, Italy.
Summary New ages of detrital zircons constrain the timing of the onset of deformation in the Ross orogen. In the Skelton Glacier area, Skelton Group was deformed before cross-cutting intrusion at 551 Ma. The youngest, significant, age-probability peaks from three samples of Skelton Group are 649 Ma, 684 Ma, and 691 Ma. The 649 Ma peak may be considered the maximum depositional age of Skelton Group, constraining the period of deformation to between 649 Ma and 551 Ma. In the upper Scott Glacier area, La Gorce Formation was deformed prior to cross-cutting intrusion at 526 Ma. The youngest, significant, age-probability peaks from two samples of La Gorce Formation are 581 Ma and 619 Ma. The 581 Ma peak may be considered the maximum depositional age of La Gorce Formation, constraining the period of deformation to between 581 Ma and 526 Ma.