Zdjęcie geologiczne fałdów Iwonicza-Klimkówki-Rymanowa

Jan Wdowiarz


Geological map of the folds in the area Iwonicz-Klimkówka-Rymanów

A geological survey of the vicinity Iwonicz-Rymanów was carried out in 1944, advantage being taken of ail natural rock outcrops in stream-beds and road-cuttings; in addition to this a dozen or so diggings were made, chiefly for the purpose of determining the axis of the anticline Iwonicz-North. The Bóbrka-Rogi fold (of the Village of Iwonicz) Well-known since long ago in the geology of the Carpathian Mountains is the Bóbrka-Rogi fold, the central part of which, containing the Cretaceons in its core, lies in the area of Bobrki, Poraj and Łężyny. To the east and west of the latter localities the above-mentioned fold gradually dips. The section discussed herein lies in the eastern part of the fold, at Iwonicz and Klimkówka, where exposed are Menilitic shales in the core at the surface, while to the south of Rymanów only Krosno strata are exposed. Among the Menilitic shales forming the core of the abovementioned fold, there are intercalations of sandstones (—20%), generally in thin layers: some of these are of the type of Krosno sandstones, calcareous, while others are siliceous, typical of the Menilitic series. In addition to these, there occur lenticular strata of spherosiderites; The wings of the fold are formed by a series of lower Krosno strata. In the bottom part of these strata there exists as if a transition of the Menilitic series to the Krosno series; this is marked by the ocurrence of Krosno sandstones and grey shales among black shales or brown ones. The F o ld of Iwonicz (North) This fold is plainly visible just below the church at Iwonicz where its distinct crest is observable in the stream-bed. The fold crest may be traced on a distance of two kilometres in an eastward direction, and then, after two faults, the crest peters out, while the fold assumes an isoclinal form. To the west of Iwonicz the cres. of this fold is observable at Rogi and at Wrocanka. The fold of Iwonicz-North is strongly inclined to the north, with an elevation in the central section between the Iwonicz stream and the fault (E). From this section the fold gradually dips westward, and still more eastward on account of the faults. This fold is formed within a series of sandstones which are thick-bedded with black and grey shales. In this region this series represents the lower Krosno strata. As the distance from the crest increases, the black shales disappear and there are more numerous intercalations of sandstones in sheets of moderate thickness. On either side there is maintained, in general, a balance in the distri encountered are lenticular beds of spherosiderites. The sandstones are strongly calcareous, and the shales are generally marly. On many strata hieroglyphs are discoverable; they are helpful in determining the position of strata, particularly in loose solitary outcrops. The sandstone series forming the core and wings of the above mentioned folds represents the lower Krosno strata. The intercalary zone is mainly occupied by a schistose series with thin sandstones; it represents here the upper Krosno strata. This synclinal zone does not manifest an undisturbed arrangement of its strata: it is secondarily folded. To the south of the sandstone zone of the northern fold observable is the axis of the synćline and, several score metres farther, the axis of the fold. The small distance between the axes is proof of the shallowness of the fold, this being demonstrated by the, appended profiles (fig. 1). This secondary folding, extending one kilometre eastward, exists within the sandstone series and, farther on, in the schistose series. The actual syncline between the Iwonicz folds lies farther south and coincides with the schistose zone, or the schistose-sandstone one, where the leading role belongs to grey marly shales, separated by thin sheets of sandstones (20—40%). This syncline is not very clearly defined, so that in some places it is difficult to trace its axis. Towards the east the Iwonicz folds (village of Iwonicz and Iwonicz-North) come somewhat closer to each other, this being proof of a lowering of the whole block in this direction. Notes on the morphology Morphologically worthy of remark is, first of all, the Klimkówka stream, particularly its old channels which it is possible to reconstruct on a certain distance in the central section. In the upper section the valley of the strongly incised stream is narrow, while in the lower section, below the church, it gradually becomes wider, forming as if the shape of a doubled funnel. The widening of the valley increases from the mouth of a larger left-bank stream; moreover, the level of the valley is higher than that of the valley of the above-mentioned stream. The main Klimkówka stream also flows in a valley which has a lower level (3 or 4 metres). The general direction of the course of the Klimkówka stream is north-east, as far as its bend to the east. The short stretch flowing from the west eastward represents a newer direction of the stream course. Formerly the stream continued in the hitherto followed direction of its course, proof of which exists in the gravel level. At the time, naturally, the level of the upper part of the stream was correspondingly higher. As incisive and lateral erosion progressed, the stream shifted a bit westward, carving out for itself a quite spacious valley, and particularly farther to the north-west, within the limits of Iwonicz. Beside this valley observable are traces of a previous higher-lying valley in the form of levels with gravel. The fact that the Klimkówka stream once flowed to the west, emptying into the Iwonicz stream, is indicated, as a matter of fact, by- the above-mentioned wide valley, within which there exists at present an insignificant brooklet, with little water, having its indistinct source among some meadows in the upper part of the aforesaid higher-lying terrace (valley) at Klimkówka. Such a small stream could not have carved out for itself such a spacious valley as the one which exists here; this work was carried out, therefore, by a larger stream. Interesting is the present-day direction of the stream course to the east, or to the north-east. From the east, to the south of the present-day manor-house, a small stream probably cut in retrogressively, causing the river, very likely when greatly swollen, to overflow into the valley of the small stream. At present this short section running west-east is strongly incised, displays a great drop, exposes rocks in the stream-bed; in short, it is a section of a young rivulet, strongly animated in comparison with the neighbouring sections. Observable is a considerable difference, amounting to more than, a dozen metres, between the levels of the old western valley and the younger eastern valley. What we have here, therefore, is a distinct case of river capture. Another question concerns the broad valley between the mouth of the stream near the manor-house at Klimkówka and the river at Rymanów. Its width amounts to more than two kilometres; farther north (after a distance of 1,5 km) the valley of the two nearly parellel rivers narrows down to less than one kilometre. In the cutting-out of such a spacious valley in this place, both rivers probably participated. The Rymanów river, meandering, shifted partly towards the west. Also in the western part of the survey the Iwonicz stream, strongly incised in the upper section, displays lower down, in the lower section, a very spacious valley. The latter occupies a large area between Iwonicz and Rogi, this being associated with the activity of the Iwonicz stream and the river Lubatówka.

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