Fig. 7

Stratigraphic profiles of paleomagnetic directions and rock-magnetic properties. a Latest age model for the Chiba composite section (Suganuma et al. 2018). b Benthic oxygen isotope stratigraphy (Haneda et al. 2020b). c Maximum angular deviation (MAD) with the 15° cut-off limit indicated, for the principal component analysis. d VGP latitude calculated from the results of the hybrid demagnetization method. e–h NRM_30-50/ARM_30-50 and NRM_30-50/IRM_30-50 as relative paleointensity indices calculated following the pseudo-Thellier approach of Tauxe et al. (1995), and linear correlation coefficients (R-value_ARM and R-value_IRM) of the indices. i Authigenic ¹⁰Be/⁹Be (Simon et al. 2019) as an independent proxy of the field intensity. j Natural remanent magnetization intensity. k Low-field (k_LF) and ARM magnetic susceptibility (k_ARM) as proxies of magnetic grain concentration. l k_ARM/k_LF as a proxy of magnetic grain size. m S-ratio at −0.3 T and −0.1 T as a proxy of the relative abundance of antiferromagnetic to ferrimagnetic minerals. New data points obtained from the Yoro-Tabuchi section are shown as blue and light blue open circles and lines, and new data points from the Yoro River section are shown as red and orange open circles and lines. Data points from previous studies (Okada et al. 2017; Simon et al. 2019) are shown as black and gray closed circles and lines. The assignment of marine isotope stages is after Haneda et al. (2020b). ARM, anhysteretic remanent magnetization; IRM, isothermal remanent magnetization; MBB, Matuyama–Brunhes boundary; MS, magnetic susceptibility; NRM, natural remanent magnetization