HR: 1330h
AN: C43A-08
TI: Seismic Reflectivity Analysis of Regional Unconformities on Ross Sea Continental Shelf: A Geophysical Fingerprint for Antarctic Ice Sheet Grounding Surfaces
AU: * Saanumi, A A
EM: adeniyi@geol.lsu.edu
AF: Dept. Geology and Geophysics, Louisiana State University, Baton Rouge, LA 70803 United States
AU: Lorenzo, J M
EM: juan@geol.lsu.edu
AF: Dept. Geology and Geophysics, Louisiana State University, Baton Rouge, LA 70803 United States
AU: Bart, P J
EM: pbart@geol.lsu.edu
AF: Dept. Geology and Geophysics, Louisiana State University, Baton Rouge, LA 70803 United States
AU: Tomkin, J
EM: tomkin@geol.lsu.edu
AF: Dept. Geology and Geophysics, Louisiana State University, Baton Rouge, LA 70803 United States
AB: Past seismic stratigraphic studies along the continental shelf of Antarctic passive margins have interpreted Cenozoic regional unconformities as ice-sheet grounding surfaces. These unconformities are manifested seismically as high-amplitude topset reflectors. In the Ross Sea, Antarctica, we model the offset-dependent seismic reflectivity patterns of these unconformities. Six multichannel seismic lines totaling ~206 km in length were run in the North-Basin sector of Ross Sea outer continental shelf in 2003. Fold coverage was 48 and recording time extended to 5 seconds. Seismic data are stacked to highlight differences in the reflector continuity and amplitudes between zero-offset-gradient and -intercept attribute stacked seismic sections. From the variation of amplitude with offset, individual common midpoint gathers are modeled for P-wave velocity, S-wave velocity, and density changes across unconformities. Beneath regional unconformity reflectors, we look for possible zones of overcompaction in anomalous changes of P-wave, density and Poisson ratio values. Unique offset-dependent reflectivity attributes may aid in the glacial unconformity interpretation of seismic reflectors.
DE: 1699 General or miscellaneous
DE: 1827 Glaciology (1863)
DE: 3022 Marine sediments--processes and transport
DE: 3025 Marine seismics (0935)
DE: 9310 Antarctica
SC: Cryosphere [C]
MN: 2005 Joint Assembly