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Detailed palaeogeographical studies of the accumulative fan in the Serteyka River valley in W Russia and underlying biogenic deposits were carried out. The base of a representative core of biogenic sediments in the distal zone is dated to 1291 BC, while its top to 1631 AD. In this paper, palynological, plant macrofossils, Chironomide and Cladocera, geochemical, geochronological and sedimentological analysis were performed. Four phases of biogenic deposition were distinguished by pollen and geochemical analyses. Two of them coincide with the climatic fluctuation during Medieval Climate Anomaly and Little Ice Age. During the formation of the fan, overbank deposits were accumulated also, indicating numerous and intense floods, which are in line with the trend observed for other sites in this region. The accumulative fan is formed by lower, middle and upper deluvia and agricultural diamicton in its top. All units have specific sedimentological and geochemical features as well as low admixture of plant macrofossils. The beginning of the formation of this relief form dates back to the second half of the 17th century AD, and the end of the accumulation falls on the second half of the 18th century AD. Our work suggests that natural conditions had an impact on the formation and development of studied accumulative fan, however, the decisive factor causing the intensification of the slope processes were related with deforestation resulted from strong human impact, which was marked in palynological and macrofossils analyses (e.g. increase in the contribution of plants macrofossils related to agriculture). [ABSTRACT FROM AUTHOR]

The extreme northeastern Europe constitutes a marginal historical transition zone from the, at least partially, agriculturally based economy of North Russia and the hunting-gathering economy of the indigenous Finnish and Samoyed peoples of the North. Climate and trade are crucial for the economy, and these are assumed to be the two main factors in understanding the regional historical development. I present a multi-archive mean annual temperature reconstruction for northeastern Europe spanning the past two millennia, which is used to develop a comparative chronology of climatic and historical events in the study region. It is argued that climate had a profound impact on the Slavic population’s economy and directions of migration, facilitating penetration into higher latitudes in warmer and abandonment in colder climatic phases. It is virtually certain that the mode and speed of development and northeastward expansion of the Russian State from the Middle Ages to the Modern Time were in many ways dependent on natural and geographical factors. [ABSTRACT FROM AUTHOR]