2.4. Demagnetization Measurements
A stepwise alternative field (AF) demagnetization method was applied to
clean the secondary magnetizations from the sedimentary samples. The
demagnetization method was carried out using a 2G Enterprises Cryogenic
Magnetometer on 44 samples divided into 3 different sequences. The first
sequence of 17 samples (shown in the leftmost column of Fig. 2c) was
demagnetized at 1 mT intervals from 0 to 49 mT and 10 mT intervals from
50 to 100 mT. The second sequence of 14 samples (shown in the middle
column of Fig. 2c) was demagnetized at 2 mT intervals from 0 to 48 mT
and 10 mT intervals from 50 to 100 mT. The third sequence of 13 samples
(shown in the rightmost column of Fig. 2c) was demagnetized at 0.5 mT
intervals from 0 to 39.5 mT and 10 mT intervals from 40 to 100 mT.
Demagnetization data were interpreted with Remasoft software (Agico
Company; Martin Chadima and Frantisek Hrouda).
ChRM directions and maximum angular deviation (MAD) values were
determined from principal component analysis (PCA) (Kirschvink, 1980) on
the Zijderveld diagram (Zijderveld, 1967). ChRM intensity values show
the intensity of the samples at ~15-20 mT AF
demagnetization according to the PCA. Virtual geomagnetic pole (VGP)
latitudes and longitudes were calculated using PMGSC software (Randy
Enkin). Supplementary Table S1 shows paleomagnetic data for each sample.
Examples of AF demagnetization results for the Matuyama and Brunhes
intervals (two examples each) are shown in Fig. 5. The rest of the
samples are shown in Supplementary Table S2 and Supplementary Fig. S3.