We report results on the age estimates of the Paleogene diatom datums derived from the magnetostratigraphy at the marine Cenozoic stratigraphic section of the Kvachina Bay, West Kamchatka. Based on a direct correlation with the Geomagnetic Polarity Time Scale, it was possible to determine the age of such levels in the interval between Subchron C13r (35.10–33.73 Ma) and Subchron C9r (27.86–27.44 Ma). Of greatest interest are the dates of the first and last occurrences of Lisitzinia ornata (27.71 Ma and 27.54 Ma respectively), and the first occurrence of Rocella gelida (27.49 Ma). This is the first experience of absolute age estimates of Oligocene diatom biohorizons based on magnetostratigraphy not only in Kamchatka sections, but in the North Pacific region in general. A comparison was made between the obtained age estimates and those published in the literature based on the study of deep-sea cores in various regions of the World Ocean.
Gladenkov et al. (2026) studied this question.