Figure 1. Variations in main characteristics of the geomagnetic field in the Neogaea: (a) reversal frequency determined from the geomagnetic polarity time scale (Table 1); (b) relative variation in the field sign, defined as the ratio of individual paleomagnetic direction determinations of a given polarity to the total number of determinations in a given time interval; (c) geomagnetic polarity bias (normal polarity percentage) determined from the polarity scale (Table 1); (d) total amplitude of direction (S) variation.