HR: 16:15h
AN: C44A-02 INVITED    [Abstracts]
TI: Seismic Facies and Stratigraphy of the Cenozoic Succession in McMurdo Sound, Antarctica: Implications for Tectonic, Climatic and Glacial History.
AU: * Henrys, S A
EM: s.henrys@gns.cri.nz
AF: GNS Science, 1 Fairway Drive, Avalon,PO Box 30-068, Lower Hutt, 5040, New Zealand
AU: Fielding, C R
EM: cfielding2@unlnotes.unl.edu
AF: University of Nebraska-Lincoln, Department of Geosciences, 214 Bessey Hall, Lincoln, NE 68588-0340, United States
AU: Wislon, T J
EM: twilson@mps.ohio-state.edu
AF: Ohio State University, School of Earth Sciences, 125 S. Oval Mall, Columbus, OH 43210- 1522, United States
AU: Naish, T R
EM: t.naish@gns.cri.nz
AF: GNS Science, 1 Fairway Drive, Avalon,PO Box 30-068, Lower Hutt, 5040, New Zealand
AU: Whittaker, J
EM: j.whittaker@geosci.usyd.edu.au
AF: Victoria University of Wellington, School of Earth Sciences, PO Box 600, Wellington, 6140, New Zealand
AU: Project Science Team, A
EM: http://www.andrill.org/support/references/appendixc.html
AF: ANDRILL Science Management Office, 126 Bessey Hall, University of Nebraska – Lincoln, Lincoln, NE 68588-0341, United States
AB: Integration of data from fully cored stratigraphic holes, including the new AND-1B drillhhole, with an extensive grid of seismic reflection lines in McMurdo Sound, Antarctica, has allowed the formulation of a new model for the evolution of the Cenozoic Victoria Land Basin of the West Antarctic Rift. The Early Rift phase (Eocene to Early Oligocene) is recorded by wedges of strata confined by early extensional faults, and which contain seismic facies consistent with drainage via coarse-grained fans and deltas into discrete, actively subsiding grabens and half- grabens. The Main Rift phase (Early Oligocene to Early Miocene) is represented by a lens of strata that thickens symmetrically from the basin margins into a central depocenter, and in which stratal events pass continuously over the top of the Early Rift extensional topography. The Passive Thermal Subsidence phase (Early Miocene to ~14 Ma) is recorded by an evenly distributed sheet of strata that thickens somewhat into the depocentre but is continuous across and over the earlier rift strata to the margins of the basin. The Renewed Rifting phase (~13 Ma to Recent is represented by intervals that thicken significantly into the basin depocentre and that are complicated by evidence of magmatic activity (McMurdo Volcanic Group). The Cenozoic stratigraphy of the southern Victoria Land Basin preserves archives of both climate change and the complex rift history of the basin, and coincidences between key stratal surfaces in seismic data and evidence for environmental change in drillcores suggest that tectonic and climatic drivers may be linked.
DE: 0726 Ice sheets
DE: 1621 Cryospheric change (0776)
DE: 8109 Continental tectonics: extensional (0905)
DE: 8169 Sedimentary basin processes
SC: Cryosphere [C]
MN: 2007 Fall Meeting