HR: 1330h
AN: GP13B-14    [Abstracts]
TI: Slumps and sediment deformation: AMS of the Gaviota and Goleta Slides
AU: * Schwehr, K D
EM: kdschwehr@ucsd.edu
AF: Scripps Institution of Oceanography, UCSD Mail Code 0208, La Jolla, CA 92093-0208 United States
AU: Driscoll, N
EM: ndriscoll@ucsd.edu
AF: Scripps Institution of Oceanography, UCSD Mail Code 0208, La Jolla, CA 92093-0208 United States
AU: Tauxe, L
EM: ltauxe@ucsd.edu
AF: Scripps Institution of Oceanography, UCSD Mail Code 0208, La Jolla, CA 92093-0208 United States
AB: During the last year, we have collected six gravity cores from the northern side of the Santa Barbara Basin for paleomagnetic deformation tests. The first two cores were collected on the smaller Gaviota Slide on the western side of the basin. These cores provide the slump end member, since one core comes from the evacuated zone while the other comes from the toe or accumulation zone. Two additional cores were collected on the toes of the much older Goleta Slides and were designed to provide an undeformed reference fabric; it was our hope that they would be mostly pelagic drape but also penetrate into the top of the deformed material. One core appears to be an excellent reference core with clear laminations, while the other has distorted laminations that show the sediment has undergone some type of deformation. In between the two slides, we collected two cores on either side of the crack that runs between the two slides to investigate creep and slope stability. All cores have been sampled at a 3 cm interval with 8cc cubes to measure anisotropy of magnetic susceptibility (AMS) and AF demagnetiziation. The Gaviota slide sediments show a dominantly triaxial fabric with some alignment of the maximum eigen values, while the drape materials from the Goleta Slide show a typical oblate undeformed fabric. There are hints of deformation at major clay layers, which we continue to investigate. Several of these cores appear to show a biogentic component to the AMS signal that fades with depth. This component has a tendency to mask the deformation signal in the top sections of the cores. The NRM inclinations of the deformed core regions tend to be shallow and erratic showing what look at first glance to be excursional features.
UR: http://schwehr.org/Gaviota/bpsio-Aug04/
DE: 1518 Magnetic fabrics and anisotropy
DE: 1522 Paleomagnetic secular variation
DE: 3022 Marine sediments--processes and transport
DE: 4219 Continental shelf processes
DE: 4558 Sediment transport
SC: Geomagnetism and Paleomagnetism [GP]
MN: 2005 Joint Assembly