Chronology of vegetation and paleoclimatic stages of northwestern Russia during the Late Glacial and Holocene

We have studied 6 reference sections of bog and lake sediments in the Lenin grad and Novgorod provinces to develop a geochronological scale for vegetat ional and paleoclimatic changes in northwestern Russia during the Late Glac ial and Holocene. Every IO-cm layer along the pear and gyttja sections (4-8 .5 m thick) was investigated palynologically and the great majority of them were radiocarbon dated. Using the data obtained, standard palynological di agrams were plotted and vegetation history reconstructed. The palynozones i ndicated on the diagrams were related to the climatic periods and sub-perio ds (phases) of the Blytt-Sernander scheme. On the basis of 230 C-14 dates o btained, we derived the geochronology of climatic periods and phases; as we ll as the chronology for the appearance and areal distribution of forest-fo rming tree species. The uppermost peat layers were dated by using the "bomb effect". We compared the stages of Holocene vegetation and pale oclimatic changes discovered for the Leningrad and Novgorod provinces with the those obtained for Karelia, which we had studied earlier using the same methodolo gy.