Abstract <p>A geohistorical analysis of the initial stages of spreading in the western and central parts of the Eurasian Basin was conducted using data from Russian and American aeromagnetic surveys of the anomalous magnetic field. The axes of linear magnetic anomalies in the age interval 53.9–40.1 Ma were identified, the rotation poles of the North American and Eurasian lithospheric plates were calculated, and a paleoreconstruction was constructed. Two stages of reorganization of the movements of the North American and Eurasian lithospheric plates were established, occurring approximately 51 Ma and ~43–40 Ma ago. In the central part of the Amundsen Basin, the absence of linear magnetic anomalies in the 24n–22n range was confirmed. It was determined that the oldest symmetrical linear magnetic anomaly identified in the central parts of the Amundsen and Nansen basins is 21n (47.8–46.2 Ma). The complex nature of the opening of the central part of the Eurasian Basin may be caused by the initial rifting along the front of Caledonian deformations.</p>