Rola kemów w rzeźbie wschodniej części Wysoczyzny Białostockiej

Abstract

THE ROLE OF KAMES IN THE MORPHOLOGY OF THE EASTERN PART OF THE BIAŁYSTOK UPLANDSummaryThe eastern parts of the Białystok Upland are rich in well preserved forms of the Middle-Polish Glaciation, referred to the North-Mazovian Stage. A considerable part of these forms consist of fluvioglacial deposits covered with a mantle of structureless materials, at some places – with patches of moraine accumulations.Among numerous fluvioglacial forms kames predominate (J. E. Mojski, 1969). To the most immense kame forms belong the table-like ones. Their areas reach up to 15 km2, and relative heights – 30 m. As a rule, these axe elevations characterized by flat to sand rather abrupt slopes.One of such forms (area 11 km2 and height – 21,2 m) is situated in the vicinity of Mieleszki, at the Upper Supraśla river. It is surrounded by a kame terrace, and the terrace in turn – by a melt-water basin filled in with peat, from the north, south and west (Fig. 1).The south-western part of this form is built up of fine-grained sands, silty sands and silts (Table I), whereas the north-eastern one – of medium-grained and fine- grained sands and of small gavels (Fig. 2). The occurrence of the coarser material in the north-eastern part, and of the finer material in the south-western one, suggests that this material has been brought by melt-waters from north-east and then laid down in a water basin of delta appearance. Such table-like forms, showing similar origin and structure, are found also at Krynki, Słoje, Szudziałów and Pieszczaniki. The other kames should the referred to the fluvioglacial ones. Common are kame swells, reaching up to 10 km in length, 2 km in width and 60 m in relative height.The largest kame swell form in the area considered is that found in the vicinity of Królowy Most, so far referred to the front moraine (J. Kondracki, S. Pietkiewicz, 1967; J. E. Mojski, 1969). This swell is about 10 km long, from 800 to 1400 m wide, and from 40 to 60 m high (Fig. 4). It is built of variously grained gravels, and sands, horizontally and obliquely bedded (Figs 5 and 6). The measurements of dips demonstrate that waters building this swell flowed from NW to SE, i.e. according to the course of the morphological axis of the swell. These features do not allow this form to be referred to the front moraine. Kame hills and hummocks, found in the area in study, like all table-like forms and swells, reveal considerably greater sizes than forms of this type in the Polish Lowland area. These are elevations, from 5 to 40 m in height, various in shape. Most of them are of limnoglacial origin, e.g. the kame hill in the vicinity of Pierożki (Figs 7 and 8); a lot of kame hills and hummocks should, however, be referred to the fluvioglacaial forms produced due to a remodelling of the large table-like forms and kame swells, as a result of melting of buried dead-ice blocks and of erosional activity of melt waters. As an example may serve here four hills situated south of Sukowicze (Fig. 7).Such a big amount of kame forms proves their importance in the present-day morphology of the Białystok Upland, and points to favouralble conditions for the generation of such considerable forms, i.e. to: 1 – a marked differentiation of morpholgy of the continental glacier substratum during the North-Mazovian Stage; 2 – considerable depths of fissures and melt-water gullies as proved by the enormous relative heights of the kame forms; 3 – continental features of climate responsible for a fact that a small amount of water could not have brought the melted material away, and gathered it in the adjacent fissures and melt-water.