High-resolution paleomagnetic records from Holocene sediments from the Palmer Deep, Western Antartic Peninsula

Thick Holocene sedimentary sections (> 45 m) cored in the Palmer Deep by th e United States Antarctic Program (USAP) and during Ocean Drilling Program (ODP) Leg 178 provide the first opportunity to examine past geomagnetic fie ld behavior at high southern latitudes. After removal of a low-coercivity d rilling overprint the sediments display a stable, single-component remanent magnetization. Two short cores that recovered the uppermost 2.6 m of sedim ent have inclinations that fluctuate about the present day inclination (-57 degrees) measured at Faraday Station, and several features with wavelength s of 10 to 20 cm appear to be correlative. However, shipboard measurements of inclination fluctuations on split-core samples from three holes drilled at ODP Site 1098 do not correlate well with each other, even though the int ensity and susceptibility data correlate very well and the overall mean inc lination for cores from each hole is consistent with the expected geocentri c axial dipole (GAD) inclination. The correlation is improved dramatically by using inclinations measured on u-channels taken from the pristine center of a split core, Consequently, the anomalous directions and the resulting poor between-hole correlation of inclinations obtained from shipboard data can be attributed to coring-induced deformation, which is common on the out er edge of ODP piston cores, and/or measurement artifacts in the split-core data. Our preferred inclination record is thus derived from u-channel resu lts. The upper similar to 25 m represents continuous sedimentation over the past 9000 yr, with an average sedimentation rate exceeding 250 cm/kyr (0.2 5 cm/yr). Given that remanence measurements on u-channels average over an i nterval <7 cm long, we obtained independent measurements of the paleo-geoma gnetic field that average over only similar to 30 yr. This high-resolution record is characterized by an inclination that fluctuates within +/-15 degr ees of the current GAD inclination. (C) 2000 Elsevier Science B.V. All righ ts reserved.