HR: 1340h
AN: GP43B-0855    [Abstracts]
TI: 30 Myr of polarity stratigraphy and relative paleointensity from Equatorial Pacific sediments (ODP Sites 1218 and 1219, Leg 199)
AU: * Lanci, L
EM: llanci@uniurb.it
AF: Facolt… di Scienze Ambientali, Universit… di Urbino, Campus scientifico SOGESTA Loc. Crocicchia, Urbino, PU I-61029 Italy
AU: * Lanci, L
EM: llanci@uniurb.it
AF: Department of Geological Sciences, Rutgers University, 610 Taylor Road, Piscataway, NJ 08854 United States
AU: Pares, J M
EM: jmpares@umich.edu
AF: Department of Geological Sciences, University of Michigan, 2534 C.C. Little Building, Ann Arbor, MI 48109 United States
AU: Channell, J E
EM: jetc@nersp.nerdc.ufl.edu
AF: Dept. of Geological Sciences, University of Florida, 241 Williamson Hall, Gainesville, FL 36611 United States
AU: Kent, D V
EM: dvk@ldeo.columbia.edu
AF: Department of Geological Sciences, Rutgers University, 610 Taylor Road, Piscataway, NJ 08854 United States
AU: Kent, D V
EM: dvk@ldeo.columbia.edu
AF: Lamont-Doherty Earth Observatory, 61 Route 9W, Palisades, NY 10964 United States
AB: ODP Sites 1218 and 1219 yielded an exceptional record of the direction and relative intensity of the geomagnetic field during most of the Miocene and Oligocene. The sedimentation rate in the Oligocene and the lower Miocene carbonate-rich pelagic sediments is > 10 m/Myr, and measurements on u-channel samples allowed a high-resolution magnetostratigraphy to be resolved. Moreover, the sediment has uniform magnetic properties that made it suitable for relative paleointensity estimates. Relative paleointensity was computed using the slope of thenatural remanent magnetization (NRM) versus anhysteretic (ARM) and isothermal remanent magnetizations (IRM) during AF demagnetization. ARM and IRM were AF demagnetized using the same alternating fields used for NRM demagnetization This high-resolution record of magnetic polarity and relative paleointensity has been used to determine whether small-scale magnetic anomalies on the ocean floor (cryptochrons) represent short polarity subchrons, intensity fluctuations of the geomagnetic field, or both.
DE: 1500 GEOMAGNETISM AND PALEOMAGNETISM
DE: 1513 Geomagnetic excursions
DE: 1517 Magnetic anomaly modeling
DE: 1521 Paleointensity
DE: 1535 Reversals (process, timescale, magnetostratigraphy)
SC: Geomagnetism and Paleomagnetism [GP]
MN: 2004 AGU Fall Meeting