Development of the late Holocene ecological environments in Eastern Primorye (Russian Far East)
L. B. Nazarova1,2,3, N. G. Razjigaeva4, L. V. Golovatyuk5, B. C. Biskaborn2, T. A. Grebennikova4, L. A. Ganzey4, L. M. Mokhova4, B. Diekmann1,2
1Potsdam University, Institute of Geosciences, Potsdam, Germany
2Alfred-Wegener-Institut Helmholtz-Center for Polar- and Marine Research, Potsdam, Germany
3Kazan (Volga) Federal University, Kazan, Russia
4Pacific Geographical Institute of FEB RAS, Vladivostok, Russia
5FRSC of RAS, Institute of Ecology of Volga River Basin, Togliatti, Russia
Keywords: South Far East, ecological environments, late Holocene climate, paleolake, chironomids, diatoms, pollen
Abstract
A 115 cm long section of lacustrine-wetland sediments from Langou I Bay (Eastern Primorye; 44°25′10,16′′, 135°54′26,08′′) has been studied. According to the developed age model, the age of the deposits was 3900 years. We performed a multi-proxy study using the methods of geochemical, chironomid, diatom, and palynological analyzes. Our investigation has shown that the development of climatic and ecological conditions on the coast of the Eastern Primorye in many respects developed synchronously with the climatic phases known for the late Holocene. Period from about 4200 to 2600 cal years BP corresponded to the first and second warm of the Japanese Jomon stages and the late Jomon transgression. The peak of summer temperatures in the area took place between 2900 and 2600 cal years BP. Cooling after 2600 cal years BP was less pronounced than in Japan (Jomon and Kofun cold stages). The reconstructed temperatures were 1 °C lower than today, while in Japan the temperatures were 2-3 °C lower than in modern time. The Medieval Climatic Optimum (Nara-Heian-Kamakura stage in Japan) was reconstructed for Eastern Primorye from 1250 to 750 cal years BP. During this period the climate was humid with summer temperatures about 1,5 °C higher than in modern time. The period between 750 and 250 cal years BP could be associated with the Little Ice Age and was characterized by a decrease in summer temperatures by 1,5-2 °C below modern level. The last 200 years have been marked by shallowing of the lake to an almost complete drying out. This period is characterized by temperature fluctuations and a warming trend.
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