New evidence of the age of the lower Maeotian substage of the Eastern Paratethys based on astronomical cycles

The lower Maeotian sedimentary rocks of the Popov Kamen section (Russia, Taman Region, Eastern Paratethys) were investigated by cyclostratigraphy methods based on magnetic susceptibility measurements. Time series analysis (Lomb–Scargle and REDFIT periodograms, wavelets, Gaussian filters) revealed statistically significant signals with 5.2–6.0m wavelength corresponding most likely to the 41,000-year obliquity cycle. These new data imply a duration of the early Maeotian regional substage of 0.9Myr, and this sets the age of the Sarmatian–Maeotian boundary to about ~7.6Ma. These astronomically tuned lower Maeotian sediments of the Popov Kamen section result in an average sedimentation rate of about 11–12cm/kyr (=90.9–83.3yr/cm) for the whole section. In the relatively deep-water setting of the lower Maeotian Popov Kamen section, no major hiatuses were detected, with the exception of an insignificant gap in the upper part of the successions. The marine transgression in the Eastern Paratethys at the beginning of Maeotian was probably caused by the opening and consequent deepening of Rifian Corridor. At the end of the Tortonian (~7.6Ma), this tectonic event terminated the restricted conditions in the Mediterranean and re-established the connection between the Mediterranean Sea and Paratethys. Therefore, the Tortonian–Messinian transition in the Mediterranean probably corresponds to the clays of the lower part of the lower Maeotian record in Paratethys, which is located above the first bryozoan build-ups and below the 1.8m thick diatomite bed in the Popov Kamen section. Our astronomically calculated age for the beginning of the Maeotian at ~7.6Ma strengthens the connection between these two transgressive events.