ENVIRONMENT DEVELOPMENT AND THE EVOLUTION OF GNILOE LAKE (SOUTH-EASTERN PRIMORYE) DURING THE LAST 3300 YEARS<a href="#FN1">¹</a>

Abstract

A continuous record of paleogeographic events in south-eastern Primorye has been reconstructed based on the deposits of Gniloe Lake. The lake is located on the northern coast of Nakhodka Bay. Starting from 3240 cal. BP. 5 warming periods were identified: 3240–2500, 1865–1653, 1330–838, 733–624 cal. BP and from the second half of the 17th century to the present; 4 periods of cooling: 2500–1865, 1653–1330, 838–733 and 624–322 cal. BP; 6 wet periods: 3240–2500, 1865–1653, 1479–1330, 1056–838, 733–624 cal. BP and last 280 years; 5 dry periods: 2500–1865, 1653–1479, 1330–1056, 838–733 and 624–210 cal. BP. According to palynological analysis, the expansion of Pinus koraiensis and dark coniferous species occurred during the second phase of the Mid-Subatlantic cooling of 1479–1330 cal. BP. In the last 150 years, the most significant changes have been associated with the anthropogenic transformation of landscapes as a result of urbanization. The area of forests and their species composition have decreased. At present, shrubs have occupied areas of the deforested oak forests. Based on the results of diatom analysis, 7 stages of the development of Gniloe Lake were identified. There was a shallow semi-open lagoon at a sea level 1–1.5 m higher than the present day about 3240 cal. BP. Cooling and decrease in humidity about 2500 cal. BP led to the formation of a slightly saline semi-enclosed lagoon. Shallowing of the lagoon about 2000 cal. BP was due to a decrease in sea level. Finally, the lagoon separated from the sea about 1450 cal. BP. The transformation of the lagoon into a fresh lake occurred around 1080 cal. BP. During the period of cooling 840–733 cal. BP the shallowing of the lake began, which continued in the Little Ice Age. The increase of the lake level associated with moderate warming and an increase in humidity began at 210 cal. BP. Traces of three catastrophic events were recorded in the sediments of Gniloe Lake – a high-intensity storm about 3000 cal. BP and 2 tsunamis around 2000 and 1560 cal. BP.