Seria Niedamirowa w świetle nowego strukturalnego podziału wschodniej części okrywy granitu karkonoskiego

January Szałamacha, Maria Szałamacha

Abstract


THE NIEDAMIRÓW SERIES IN THE LIGHT OF A NEW STRUCTURAL SUBDIVISION OF THE EASTERN PART OF THE KARKONOSZE GRANITE COVER

Summary

Evidnces are presented in this paper that the Old-Palaeozoic rocks from the eastern part of the Karkonosze granite cover, referred by J. Svoboda (1956) to the Sub-Sudetic series, and considered by the present authors (M. Szałamacha, J. Szałamacha, 1958) to be the so-called Niedamirów series, extend farther to the north than it has been given by G. Berg (1912).
Based on the results of the researches made by J . Chaloupsky (1958) the authors discuss the stratigraphy of the eastern part of the Karkonosze granite cover, and define the rocks of the Kowary series (Sudetic series of J. Svoboda, 1955) to be Pre-Cambrian.
The rocks of the Niedamirów series, being part of the Sub-Sudetic series (J. Svoboda, 1955) in which graptolites were found by J. Chlupac (1953) near Żelazny Bród, and by J. Chaloupsky and R. Horny 1965) in the Izera River valley (vicinities of Ponikel) are thought by those authors to be of Cambro-Silurian age.
Microscope examinations of the rocks from the eastern part of the Karkonosze granite cover point to a very interesting tectonic effect that consists in a fact that microscope picture of rock accurately reflects style of megastructure. It is proposed to call this phenomenon an “escalation of structures”.
Taking this phenomenon into account the authors characterize the rock series investigated as follows: the Niedamirów series, thought to be a separate rock complex, shows, as compared with the Kowary series, strong plastic deformations. It is built up of massive rocks (green stones, quartzites, limestones and leptinites), and of plastic rocks (phyllites). This mechanically anisotropic rock complex, consisting of heterogeneous material, produces, due to tangential deformations, certain folds of disharmonic type. The Kowary series, also heterogeneous, consisting of rocks characterized by a high mechanical competency (gneisses and quartzites), and of incompetent rocks (micaceous schists), should have undergone disharmonic folding there. However, field observations and examinations of thin slides demonstrate that folds produced due to bending are found in all rock varieties. It is characteristic here that recrystallization of rock-forming minerals in schists is of post-deformational nature, whereas in the formations of the Niedamirów series, the recrystallization is of syntectonic character.
The data mentioned above distinctly point to the presence of a phase of orogenic activity, which has embraced the older, already metarmorphosed and deformed rocks of the Kowary series, and the overlying younger non-metamorsphosed and non-deformed deposits of the Niedamirów series. This activity resulted in a metamorsphosis of the deposits of this series, and in a formation of folds with a W–E direction.
N–S directions of fold axes, observed in the Niedamirów series, reflect some deformations connected with an overfolding of the Leszczyniec unit on the Niedamirów series. Taking this into account, the authors correct the previous subdivision and, in consequence of this, distinguish here the following there tectonical units: A – Karkonosze unit, B – Niedamirów unit, C – Leszczyniec unit.
In the new scheme, the Karkonosze unit would embrace rocks of the Kowary series, and would extend as far as the Ręziny area (Fig. 3-D). According to the recent data, the Niedamirów unit, comprising the deposits of the Niedamirów series, would reach the Bóbr River valley, near Janowice Wielkie.
An increased metamorphosis of the rocks of the Niedlamirów series, advancing from south to north, is a result of complex thermal processes (intrusion of the Karkonosze granite), and of dynamical forces (instead of maximum compression during the relative movement of the Leszczyniec series towards the Niedamirów series).


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