Japan Geoscience Union Meeting 2022

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[J] Oral

S (Solid Earth Sciences ) » S-EM Earth's Electromagnetism

[S-EM15] Geomagnetism, paleomagnetism and rock magnetism

Sun. May 22, 2022 9:00 AM - 10:30 AM International Conference Room (IC) (International Conference Hall, Makuhari Messe)

convener:Tetsuro Sato(Earthquake Research Institute, The University of Tokyo), convener:Yutaka Yoshimura(Faculty of Social and Cultural Studies, Kyushu University), Chairperson:Tetsuro Sato(Earthquake Research Institute, The University of Tokyo), Yutaka Yoshimura(Faculty of Social and Cultural Studies, Kyushu University)

9:00 AM - 9:15 AM

[SEM15-01] A preliminary paleomagnetic study using an oriented-boring core on the base of Quaternary of the Plio-Pleistocene marine sedimentary succession in the southern Boso Peninsula, Japan

*Makoto Okada1, Joan WIlly Songeons2 (1.Department of Earth Sciences, College of Science, Ibaraki University, 2.Graduate School of Science and Engineering, Ibaraki University)

Keywords:Gauss-Matuyama geomagnetic reversal boundary, oriented boring, Northern Hemisphere Glaciation

The Chikura Group is a Plio-Pleistocene marine sedimentary succession distributed in the southernmost part of the Boso Peninsula. It has a strong and stable magnetic signal and abundant marine microfossils. From this nature, the Chikura Group is suitable for paleomagnetic and paleoceanographic studies. To obtain a detailed paleomagnetic record of the Gauss-Matuyama geomagnetic reversal boundary, which is the stratigraphic guide to indicate the base of the Quaternary System, and a paleoceanographic record of the Northern Hemisphere Glaciation (NHG), we conducted to take an oriented-boring at around the base horizon of Quaternary in the Chikura Group. As a result, we have successfully collected a core consisting of almost continuous sandstone-siltstone alternation over 51 m long. We have done core splitting, image scanning, and various kinds of non-destructive measurements using the Kochi Core Center (KCC) open facility system; preliminary mini core sub-sampling, rock-magnetic and paleomagnetic measurements using the KCC joint-use program. Initial paleomagnetic measurements confirmed a VGP motion across the equator and a paleointensity trough associated with the Gauss-Matsuyama boundary at around the 10 m horizon.