Podział i rozwój facjalny retu w Górach Swiętokrzyskich

Hanna Senkowiczowa




In the marginal area of the Święty Krzyż Mountains the Roethian deposits are lithologically variously developed. One distinguishes here a sand-clay-marly lithofacies connected with the marginal zone of the basin, a calcareous-marly-sulphate lithofacies that contacts with the zone of lagoons, and a calcareous-marly lithofacies of marine origin (Fig. 2). During sedimentation of the Roethian a shallow marine basin existed in the area of the Święty Krzyż Mts; it gradually became shallower towards northeast. In the marginal part of the basin the lagoon deposits intertongue with the marine ones through the delta, fluviale and lacustrine, partly also dune deposits. Such a kind of sedimentation took place within the central and eastern parts of the northern margin. In the western portion of the northern margin the Roethian deposits were formed in a shallow marine basin, or in the lagoon zone, and in the southern and partly western margins these were laid down in a shallow, but typical marine basin. The first marine transgression reached the Święty Krzyż Mts. at the beginning of the Roethian, and the basin gradually widened its extent to reach its maximum at the dose of the Lower Roethian time. Then the sea partly withdrew from the area of the Święty Krzyż Mts. thus enlarging the areas of lagoonal and river sedimentation. During the upper part of the Roethian there is the second marine transgression, at the time of which almost the whole area of the Święty Krzyż Mts. is under the influence of marine conditions. In the uppermost part of the Roethian an insignificant shallowing of the sedimentary basin takes place in the eastern region of the northern margin area. This causes a formation of river deposits here, and in the remaining area the marine basin continues, the Roethian sea passing into the Muschelkalk sea. As a basis for the subdivision of the Roethian were taken lithological changes there. In the Roethian of the Święty Krzyż Mts. several series have been distinguished, characterizing four main stages of development of the basin. These are: begining of the sea transgression, first maximum of the sea transgression, regression of the sea and repeated transgression. The deposits laid down during the two former stages have been referred to the Lower Roethian, those of the two latter - to the Upper Roethian.


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