Wpływ budowy strukturalnej i morfologii paleozoiku Gór Świętokrzyskich na rozwój osadów triasowych

Abstract

INFLUENCE OF PALAEOZOIC STRUCTURE AND OF MORPHOLOGY OF THE ŚWIĘTY KRZYŻ MTS. AREA UPON THE DEVELOPMENT OF TRIASSIC DEPOSITSSummaryIt results from the observation of the Triassic deposits occurring in the marginal area of the Święty Krzyż Mountains (Central Poland) that their development has been conditioned by the morphology of the pre-Tertiary substratum and by its tectonical structure. After the time of Hercynian orogeny, the dislocated and folded area of the Święty Krzyż Mts. was a terrain of an intense denudation that persisted up to the close of Permian. At the Triassic time, the area under consideration was more or less smooth, having some mountainous chains that ran in accordance with the Hercynian folding direction. In the Lower and Middle Triassic, the Palaeozoic ridges, constituting islands within sedimentary basins, were intensely eroded. Complete erosion in this area took place only at the time of Lower Muschelkalk. Beside morphology, tectonical structure of the substratum was the second factor deciding upon the development of the Triassic. In Palaeozoic, the Święty Krzyż Mts area was of bipartite character. The southern part, developed still, during the Caledonian orogeny, was characterized by greater stability than the northern pan that, throughout a considerable portion of the Palaeozoic, was of geosynclinal nature, and underwent folding only during the Hercynian orogeny. The researches of the Triassic deposits occurring in the region considered illustrate that at the Buntsandstein time the stable southern area, called the Przedbórz - Kielce area, was markedly elevated, as compared with the northern one, the so-called Radoszyce - Łysogóry area. At the Roethian and Muschelkalk times the difference in sedimentation within either areas was less visible. Sedimentation of the Keuper, the deposits of which were strongly eroded during the Cimmerian orogeny at the break of Keuper and Rhaetian, can hardly be estimated, as well. The Rhaetian deposits, too, did not give any data as to reconnaissance of the Rhaetian sedimentation. On the other hand, it is known that at the Liassic time an intense sedimentation took place in the northern part, and the southern area was elevated so that Liassic deposits were laid down locally only. The development of the Lias was conditioned also by the presence of transversal elevations. These latter are connected with the structural nature of the Palaeozoic substratum. The transversal elevations conditioned also facial development and lithological character of the deposits under consideration.