georefid:1999-047933SEDIS Publication Catalogue

ana.macario@awi.de

http://sedis.iodp.org/pub-catalogue/informationpointOfContact2011-06-23T00:00:00Zhttp://sedis.iodp.org/pub-catalogue/index.php?id=1999-0479331998-01-01publicationgeorefid:1999-047933Sakai, HideoToyama University, Department of Earth Sciences, Toyama, JapanauthorKikawa, EiichiGeological Survey of Japan, JapanauthorIshihara, TakemiauthorKobayashi, HironoriauthorKomori, KiyoshiauthorSunagawa, AikoauthorNational Institute of Polar Research, Tokyo, JapanpublisherdocumentHardcopyIn: Anonymous, Proceedings of the National Institute of Polar Research seventeenth symposium on Antarctic geosciences11222-238Paleomagnetic study is conducted on sediment cores from the Antarctic Ocean off the Central Wilkes Land margin, the Dumont d'Urville Sea and Victoria Land Basin. The Brunhes/Matuyama geomagnetic polarity boundary (B/M boundary; 0.78 Ma) and the Jaramillo geomagnetic event (0.99-1.07 Ma) are identified in five cores at the Central Wilkes Land margin. One core from the Victoria Land Basin shows the B/M boundary. The assigned magnetostratigraphical age indicates the sedimentation rate of between 3 and 5 mm/ky. The susceptibility variation with depth is studied. The upper sequence younger than 0.4 Ma shows variation with larger amplitude than that of the lower sequence; however, the average and frequency dependence of susceptibility do not show distinct changes. This suggests a change of sedimentary environment around 0.4 Ma, which may be correlated with the global climate change. The magnetic intensity normalized by susceptibility shows a distinct decrease around B/M boundary; the intensity is higher in the Brunhes epoch than that in the Matuyama epoch. The result is similar to the variation of geomagnetic dipole moment studied by J. P. Valet and L. Meynadier (Nature, 366, 234, 1993) on the ODP cores from the Pacific. Ocean. This suggests that there was a global change of geomagnetic field intensity, between the Matuyama reversed epoch and the Brunhes normal epoch.completedQuaternary geologyAntarcticaCenozoiccoresDumon d'Urville Seamagnetizationmagnetostratigraphymarine sedimentsnatural remanent magnetizationpaleomagnetismQuaternaryremanent magnetizationsedimentsupper QuaternaryVictoria LandWilkes LandEnglishgeoscientificInformation113.0000115.0000-64.0000-63.0000