Big Lost Geomagnetic Excursion Recorded in the Loess-Paleosol Sequence in the Southern Part of European Russia, Otkaznoe Section

The paper presents the results of detailed rock magnetic and paleomagnetic studies of the Lower Pleistocene loess-paleosol sequence (LPS) in the Otkaznoe section (Terek-Kuma Lowland). For the first time, the Early Brunhes geomagnetic excursion was recorded in the Otkaznoe section for loess sections in the southern part of European Russia and its continuous paleomagnetic record was obtained. The revealed excursion, covering a 0.22 m zone, is characterized by anomalous/intermediate paleomagnetic directions and the latitudes of the virtual geomagnetic pole (VGP) ∼30° and correlates with the marine isotope stage (MIS) 14. The age of the geomagnetic event, determined based on the correlation of variations in magnetic susceptibility with the global oxygen isotope curve (δ18O), is ∼540 ka, and its duration is estimated at 2–3 ka. The data obtained make it possible to identify the excursion in the Otkaznoe section as the Big Lost geomagnetic event and use it as a reliable chronostratigraphic marker for regional and global correlations.