Natural middle-and late-Holocene environmental development of Kunashiri Island reflects global climatic changes and the migration of warm and cold currents. Dry and cool climate changed to warm and moist about 7000–6500 BP, later than on Hokkaido Island. At this time Kuroshio Current system became more active. On Kunashir Island birch assemblages were replaced by cool-temperate broadleaf forests in the south and mixed coniferous/broadleaf forests in the north. The highest sea-level position reached 2.5–3 m above PSL about 6500–6300 BP. Cooling about 4700–4500 BP island vegetation weakly changed that connected with warm current influence. Major regression at this period led to formation of extensive coastal dunefields. The warming at the beginning of the late Holocene was almost similar to the Holocene Optimum. Two minor transgressions are recorded about 4010–3400 and 2950–2620 BP. Active entrance of detrital material to the coastal zone resulted in growth of accumulative landforms. Vegetation changes and climatic deterioration took place in the second half of the late Holocene. Coniferous and mixed coniferous/broadleaf forests shifted southward and occupied a large part of the island. During cooling at 1700–1300 BP the isthmus area increased, coastal wetlands with lakes and coastal dunes were formed, and grassland and swamp landscapes developed. Late-Holocene warming was not intensive. Active aeolian accumulation took place during the ‘Little Ice Age’ cooling and regression.

No abstract

No abstract

No abstract

The study of Holocene deposits on Iturup Island is very important for understanding palaeolandscape changes on the island. It is separated by deep straits from the neighbouring islands and was isolated during the last glacial maximum. Landscape changes over the last 40000 years and the role of refugia on vegetation development are discussed. Changes in natural processes in this region were controlled both by global climatic changes and by regional factors. Birch forests developed at the warming about 36-37 ka ago, whereas tundrapark landscape developed with the cooling of the last glacial maximum. Holocene environments reflect climatic changes and sea-level oscillations. The fluctuation of warm and cold currents influenced the landscape development. At the Holocene Optimum (about 6 ka) broadleaved forests with Quercus, Phellodendron, Carpinus, Juglans, Fagus, Fraxinus and Syinga occupied the Okhotsk side of central Iturup. Climate was warmer than present and the sum of active tempe]ratures (σ ≥10°C) was not less than 1800°C. The warming was coincident with the transgression with the highest sea level up to 3.5 m above present sea level (PSL). Numerous coastal lakes were formed at this time. A shallow strait occurred on the low Vetrovoy isthmus. The sea-level drop at 4700-4500 radiocarbon years BP led to the development of large dunefields only within bays with a flat coast due to the supply of sandy material from the inshore drainage zone. At the beginning of the late Holocene about 4000 BP the vegetation changed very little due to the warm current influence. Cool-temperate forests with dominant Quercus had a wide distribution, but the diversity of broadleaved genera decreased. A minor transgression occurred about 4100-4000 BP with a sea-level rise on about 2.5 m above PSL. Active accumulation of deposits took place in the coastal zone at this time. Great vegetation changes and climatic deterioration took place in the last 2000 years BP. Cool-temperate broadleaved forests were confined to the Okhotsk side of the central island. Grasslands and swamps also developed in the coastal lowlands at this time. A minor regression led to the formation of large dunefields. Isthmuses increased and coastal wetlands with lakes formed. The presence of marine diatoms in floodplain lake deposits indicates a sea-level rise at about 1060 ± 60 BP. At this time warming was not intensive, but was well pronounced. The last phase of active aeolian accumulation took place during the ‘Little Ice Age’ cooling and regression.