On the basis of changes in grain size composition, third-order symmetrical cycles are clearly distinguished in the L.Miocene. They reflect the pulsating nature of the supply of clastics from the shelf to the continental slope. The M. Miocene is dominated by second-order cyclic recurrence caused by long-term stable orogenic movements. There is heterogeneity of the sandy material controlled by a periodically increasing supply of eolian and volcanogenic material to the continental slope. -after Authors