Paleomagnetic study of marine sediments from Antarctic Sea-Central Wilkes Land margin, Dumon d'Urville Sea and Victoria Land Basin-

• Main Authors: Sakai,Hideo, Kikawa,Eiichi, Ishihara,Takemi, Kobayashi,Hironori, Komori,Kiyoshi, Sunagawa,Aiko
• Format: Report
• Language: English
• Published: Department of Earth Sciences, Faculty of Science, Toyama University/Global Environmental Laboratory, Faculty of Education, Toyama University/Marine Geology Department, Geological Survey of Japan/Department of Earth Sciences, Faculty of Science, Toyama University/Global Environmental Laboratory, Faculty of Education, Toyama University/Global Environmental Laboratory, Faculty of Education, Toyama University 1998
• Subjects: magnetization of sedimentary cores; geomagnetic polarity reversals; Antarctic Sea; Brunhes/Matuyama boundary; secular change of geomagnetic intensity; Antarctic; The Antarctic; Victoria Land; Pacific; Antarctic Ocean; Wilkes Land; Dumont d'Urville; Dumont-d'Urville; D'Urville Sea; Valet; Antarc*; Dumont D'Urville Sea; Polar geoscience
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=3030; http://id.nii.ac.jp/1291/00003030/; https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=3030&item_no=1&attribute_id=18&file_no=1

Paleomagnetic 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