Analiza sieci uskokowe jednostki łysogórskiej na podstawie fotointerpretacji

Abstract

AN ANALYSIS OF THE FAULT NETWORK WlTHIN THE ŁYSOGÓRY UNIT (HOLY CROSS MTS CENTRAL POLAND) BASED ON PHOTOINTERPRETATlON METHODS

 SUMMARY

An analysis of the fault network is presented for the Łysogóry unit in the Holy Cross Mts, Central Poland. This unit, built up of the Middle and Upper Cambrian, Ordovician and Silurian deposits (Fig. 1), has a simple monoclinal structure with, some secondary disharmonic disturbances, and it is bordered from the south by the Holy Cross, dislocation which is the greatest fault in the Holy Cross Mts, presumably a deep-seated one and reaching the Moho surface (cf. Kutek & Głazek 1972, Guterch & at 1976).
The photointerpretation has been based on air photograms of the scales 1:16,800 through 1:18,800 (Fig. 2), and on space aerograms of the scale 1:250,000, taken by Landsat-2; of the latter, analysed were (Fig. 3B) the bands 6 and 7 that correspond to the wave lenghts 0.7–0.8 and 0.8–1.1m. Morphologic map of the scale 1:100,000 with contours every 5 m was also taken into account, as it is comparable to small-scale radar photograms; interpretation has been surveyed by the Ronchi ruling (Fig. 3A). All these materials, as being of diversified scales, display different elements of the disjunctive tectonics.
The Holy Cross dislocation is weakly readable in all these three interpretations (compare Figs 2, 3A and 3B), and better recognizable is only its central part (compare Figs 2 and 3A). There appears however a distinct, hitherto unknown longitudinal fault zone that stretches along the Silurian occurrence belt (see Figs 2–3); other longitudinal faults are small and occur only in some areas.
Main transverse faults (cf. Fig. 1) display commonly the nature of the fault zones within which the particular faults are generally normal. All these faults recognized by the photointerpretation methods are well pronounced in morphology, and this is demonstrated the best by the Łysogóry transverse fault (Fig. 4).
The photointerpretation allowed to recognize a great number of diverse small faults (Figs 2 and 3A) which are not visible in the field. These faults have been analysed statistically to show their maxima that do not correspond to the joint system of the Łysogóry area (Fig. 5A); they well agree however with the joint system of the Mesozoic margins of the Holy Cross Mts (Fig. 5B). Consequently, these small faults are to be regarded as originated simultaneously with joints of the Holy Cross margins, presumably during the Laramide tectonic movements (cf. Jaroszewski 1972, Kutek & Głazek 1972, Mizerski 1976). On the other hand, good readability of many of the faults (both transverse and small ones) investigated by photointerpretation methods may evidence their, neotectonic activity.