Magnetostratigraphy and palynology of the lower Pleistocene loess-soil sequences in the upper Don River basin

A geomagnetic excursion is detected and studied in detail in the loess-soil sequence of the upper Don River basin. This event, termed as the Log Krasnyi excursion, happened about 600 ka ago. Characteristic features of this reversed polarity excursion consist in stepwise changes of polarity and lower intensity (by 3-4 times) of the geomagnetic field, as compared to this parameter of the stationary field. Palynological data show that the formation period of studied rocks included 7 warming and 9 cooling phases. The time range of the first half of the excursion corresponded to the period of cold climate, whereas its later stage consisted of two optimum phases. The commencement and cessation of the excursion are correlative with abrupt climatic changes. It is demonstrated that the Log Krasnyi excursion can be used to refine the Cromerian stratigraphy.