ИСТИНА

The geomagnetic superchrons, prolonged periods (> 20 Myrs) of stable magnetic polarity documented both during the Paleozoic and the Proterozoic, represent one of the most enigmatic events in the history of the Earth’s magnetic field. Acquiring a deepened knowledge of such events is of utmost importance to understand the origin of superchrons and better constrain geodynamo models. In our report, we present new paleomagnetic data allowing the estimation of the directional variability (the so-called paleosecular variation, PSV) of the Earth’s magnetic field during the Cretaceous Normal Superchron derived from the study of the lava flows from the Okhotsk-Chukotka volcanic belt which has been formed in the late stage of the superchron between 90 and 85 Ma. We further compare our estimates with well-constrained data for the last 5 Ma and discuss the possible dependency between geomagnetic reversal rate and PSV amplitude. The works have been supported by the RSF grant # 19-47-04110.