Home – Home – Jornals – Russian Geology and Geophysics 2025 number 9

A continuous record of paleogeographic events of the Holocene has been reconstructed based on biostratigraphic study and radiocarbon dating of the coastal peat bog in Nerpichy Bay, the Sea of Okhotsk. Development of zonal landscapes since the end of the late Pleistocene began from shrub forest-tundra to birch elfin forest with the first appearance of broadleaved trees in the early Holocene (about 10 cal ka BP), dominance of dark coniferous taiga with maximum participation of broadleaved trees in the middle Holocene, their further decrease in the late Holocene and almost complete disappearance at present. On the coast peat began to accumulate when temperature increased, about 10.2 cal ka BP. A rapid change of the swampy larch forest, after large-scale fires, to a community dominated by true mosses, and then to subshrub-grass-sphagnum phytocenoses was a peculiar feature of the bog ecosystem evolution. Further successions occurred with a gradual replacement of eutrophic-mesotrophic sphagnum mosses by oligotrophic Sphagnum fuscum ; for the latter the highest rates of peat accumulation were noted to be at 7.2-6.1 cal ka BP. At that time the average annual temperature was approximately 2 °C higher than the present, and the long-term average annual precipitation was approximately 40 mm higher than at present. The most pronounced cooling periods in the Holocene occurred at 10.6-10.2, 9.2-8.9, 8.3-8.0, 5.2-4.8, 4.3-4.0, 3.5-3.3, 2.8-2.5, 1.5-1.0 and 0.6-0.4 cal ka BP. The cooling events identified in the southwestern coast of the Sea of Okhotsk are consistent with the sequence of cold events of the Holocene both in the region and in the Northern Hemisphere.