Interglaciał eemski w Gołkowie koło Warszawy

Zofia Janczyk-Kopikowa

Abstract


EEMIAN INTERGLACIAL AT GOŁKÓW NEAR WARSAW

The series of the organic deposits, developed in the vicinity of Gołków near Warsaw as oil shales and peats, was laid down in a trough valley and now rests .on the deposits of the Middle Polish Glaciation (Riss). The organic deposits are .overlain by the fluviale deposits of the North Polish Glaciation (Würm). The locality Gołków occurs beyond the extent of the continental glacier of this glaciation.

Polen analysis completed by microfloristic examinations allows to determine the age of the organic series that is thought to be Eemian. The pollen diagram from Gołków does not call in question the stratrgraphical position of the deposits investigated mainly due to its characteristic features such as minimum content of coniferous trees in the climatic optimum - about 5%, high percentage of Coryluls - 77,5% and well developed phase of hornbeam. It may be well ·compared with other Eemian diagrams from the area of Poland and reveals much similar features.

The development of vegetation at Gołków·has depended upon the prevailing climate. At first, the cool climate brings about the development of plants having small thermal requirements. Here being thin, park-like forests with pine and birch (Pinus, Betula) accompanied by the heliophilic plants such as Hippohäe and Ephedra. Improvement of climate that becomes warm and humid provides for development of deciduous forests prevailing in the climatic optimum of the Interglacial. Decrease of temperature causes a repeated change in the type of forest. This latter changes into coniferous forest with prevailing spruce (Picea) and fir (Abies) at the beginning and then with pine (Pinus) and birch (Betula). During the Eemian Interglacial, the development of plants at Gołków terminates with a new and long-lasting predominance of pine-birch forests. However, such a longevity may be apparent only. Apparent character of this phenomenon is proved by a fact that the pollen spectra of the warm climatic periods have found their reflex in the oil shale that increased considerably slower than the layers of feebly decomposed peat evidencing the existence of cool pine-birch forests from the decline of the Interglacial.

The water basin, in which the pollen grains were laid down from surrounding plants, is characterized by a calm sedimentation as proved by the occurrence of the oil shale. An insignificant water flow left behind some thin sand laminae. The not too deep basin becomes shallower owing to the growing water vegetation, and marshy vegetation. The growing of the plants causes a complete shallowing of the basin and formation of peat bog in situ, as proved by the peat beds occurring in the section.


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