CONFERENCE ON MODERN WAYS AND METHODS OF STUDYING SWAMPS

摘要

The performed investigations made possible to distinguish three phases in the for mation of the vegetation cover. The first corresponds to the layer of covering sandy loans and loamy soils which stretch out under the bed of peats and saprobes. As to age it belongs to the transitional period from the ancient to the early Holocene, and it dates approximately 10,000 years. In this time, the vegetation belts were displaced to the north.nThe second phase is the period of accumulation of the lower layers of contemporaneous organogenic depositions. It was distinguished by strengthening of the continental climate, drop in winter temperature, which led to the reduction of the wooded area and to a replacement of the original landscapes with colder ones.nThe third phase corresponds to the middle. Holocene at which time the larger portion of the peat bed was formed. Compared with the preceding phase, the climate became more moist and hot, and characteristic is the spread of spruce forests to the north, formation of the taiga and forest steppe landscapes with the predominance of common pine, wide spread of the Siberian stone pine and the fir. In the contemporaneous phase, an energetic advancement of the Common pine to the north, and a reduction of the spruce tree growth are observed under the degrading influence of eternal frost. Study of the surface samples showed that. small amounts of pollens are met with in the samples even in the areas of their overwhelming predominance. The content of spruce and fir pollens is usually 2-3 times less than the share of these species in the forest cover.