HR: 0800h
AN: T11A-1230    [Abstracts]
TI: Fault Patterns Within the Eastern Terror Rift, Western Ross Sea, Antarctica
AU: * Hall, J M
EM: hall.848@osu.edu
AF: Dept. of Geological Sciences, Ohio State University, 125 S. Oval Mall, Columbus, OH 43210 United States
AU: Wilson, T J
EM: wilson.43@osu.edu
AF: Dept. of Geological Sciences, Ohio State University, 125 S. Oval Mall, Columbus, OH 43210 United States
AU: Henrys, S
EM: S.Henrys@gns.cri.nz
AF: Institute of Geological and Nuclear Sciences, PO Box 30368, Lower Hutt, 0000 New Zealand
AU: Horgan, H
EM: hhorgan@geosc.psu.edu
AF: Institute of Geological and Nuclear Sciences, PO Box 30368, Lower Hutt, 0000 New Zealand
AB: The Terror Rift region is an important key to understanding the timing and kinematics of neotectonic rifting between East and West Antarctica. In January/February 2004, a 30-day geophysical cruise (NBP04-01) was conducted in the western Ross Sea with the goal of analyzing faulting associated with the Terror Rift. New, east-west, multichannel seismic reflection profiles (line spacing between 5-15 km) have revealed new details about a prominent fault zone striking generally N-S between 166řE and 167.5řE within the western Ross Sea. The fault zone can be traced along strike for at least 150km. Initial comparison to previous seismic surveys correlates this fault zone with the margin of the "Discovery Graben" and the "Lee Arch" in the eastern part of the Terror Rift. Our new lines show that the faults clearly have normal displacement, having down-to-the-west offset in the east, and down-to-the-east offset in the west. Bedding in the fault zone defines an antiformal structure, and faults change dip and sense of normal displacement across the antiformal hinge zone. On some seismic profiles a prominent unconformity truncates the stratigraphic interval affected by intense faulting, with fewer younger faults cutting the unconformity and reaching the seafloor. On other lines the interval of intense faulting is at the seafloor and the unconformity is absent, possibly indicating more recent glacial erosion. Comparison of the reflectors and unconformities within this fault zone to the dated cores of the Cape Roberts Project should allow us to reconstruct a detailed interpretation of the timing and history of rifting in the region.
DE: 9310 Antarctica
DE: 8010 Fractures and faults
DE: 8107 Continental neotectonics
DE: 8109 Continental tectonics--extensional (0905)
DE: 3025 Marine seismics (0935)
SC: Tectonophysics [T]
MN: 2004 AGU Fall Meeting