High southern latitude magnetostratigraphy and rock magnetic properties of sediments from Sites 747, 749 and 751

Abstract

The magnetostratigraphy of Sites 747, 749 and 751 of Leg 120 that was established by shipboard measurements was extended and confirmed. 580 sediment cubes were stepwise demagnetized with alternating fields to determine their characteristic remanence. A rather complet magnetostratigraphy was obtained from the Oligocene to the Pliocene for the nannofossil oozes of Site 747. The magnetic carriers are single-domain and small pseudo-single-domain (titano)magnetite particles. A fraction of these Fe-Ti oxides seems to reside as microlites in the vitric volcanic ash particles that were enriched in the magnetic separates. The natural remanent magnetizations seem to be of detrital origin with small Fe-Ti oxide grains in the volcanic glass particles as carriers of the stable paleomagnetic signal. -from Authors