СТРАТИГРАФИЯ ВОДОРАЗДЕЛЬНОГО ТОРФЯНИКА И РАЗВИТИЕ ПРИРОДНОЙ СРЕДЫ ОСТРОВА БОЛЬШОЙ ШАНТАР В ПОЗДНЕЛЕДНИКОВЬЕ–ГОЛОЦЕНЕ

Abstract

Continued record of paleogeographic events in the Shantar islands since the end of the Pleistocene was restored on the basis of a multy-proxy study of the stratigraphy of the blanket peatland. Biostratigraphical studies included botanical, diatom and pollen analyses. The age-depth model was built using 7 radiocarbon dates. For the first time, data of the environment development were obtained for the coldest part of the Sea of Okhotsk. Synchronicity and metachronicity of paleoclimatic events with regional data and global changes have been established. The Younger Dryas on the Shantar islands was much colder than in other areas around the Sea of Okhotsk. The climate became more maritime after the isolation of the islands at the early-middle Holocene. The influence of the cold sea and the presence of drifting ice were one of the main factors, why the early and middle Holocene optimums were poorly manifested here, and also determined the specifics of climatic rhythm. Models explaining alternation of relatively warm and cold periods with different humidity are proposed. The age of periods with heavy snowfalls has been established, as evidenced by the change in the role of shrub pine in island vegetation. Phases of development of local swamp and zonal landscapes are highlighted. Spruce appeared on the area ~11410–10345 cal. yr. BP, when there was a landbridge, and spruce trees became common in the middle Holocene and especially at the boundary of the middle-late Holocene. One of the controlling factors for the development of swamp landscapes was thermokarst processes. Significant changes in the environment occurred in the Little Ice Age, the most severe conditions were ~500–260 cal. yr. BP. In the last 210 years, the most significant changes in landscapes have been associated with anthropogenic fires.