Wapień muszlowy w zachodniej Polsce

Abstract

MUSCHELKALK IN WEST POLANDSummaryThe present paper is an attempt at making a lithologic-stratigraphical correlation of the Muschelkalk from two areas: western part of the Fore-Sudetic monocline and West Pomerania (Fig. 1). Within the areas here considered Muschelkalk members occur. In the axial part of the sedimentary basin, running within the southern part of the Fore-Sudetic monocline approximately along the line Świebodzin-Książ Wielkopolski, the thickness of the Muschelkalk deposits ranges from 250 to 280 m. Northwards, the basin becomes shallower, and the thickness diminishes, amounting to about 100–170 m (Fig. 2). According to the gradual reduction in thickness from south to north we may also observe changes in the lithological development of the sediments. Both mary beds and series of wavy limestones of the Lower Muschelkalk in West Poland reveal only slight lithofacial changes. These, however, distinctly point to the presence of a shallower zone of the basin in the north. These changes consist in the appearance of visibly more marly deposits in the north, frequently brown in colour, with arenaceous intercalations (Jarkowo, Połczyn Zdrój, Kamień Pomorski). The series of pumiceous limestones (series “c”) of the Lower Muschelkalk is facially more differentiated. Typical deposits of pumiceous limestone facies, found to occur in the southern part of the basin reaching northwards as far as the area of Gorzów Wielkopolski, at first give way to relatively poor beige-coloured limestones and then to mady limestones and in colour frequently of wavy structure.A regressive nature of the Middle (Muschelkalk basin was characteristic of the western areas of Poland, where mainly dolomite-sulphate formations were laid down (Sulechów, Książ Wielkopolski, Gorzów Wielkopolski) along with a greater amount of clay intercalations in the north (Rokita, Kamień Pomorski). In the more peripheral portions of the basin, the dolomite-sulphate formations pass into dolomite-clay ones, and sulphates may be encountered sporadically, only in the from of slight impregnations (Połczyn Zdrój, Jarkowo, Ustronie Morskie).At the Upper Muechelkalk time, the form of the basin was the same as that in the Middle and Lower Muschelkalk. There may be observed here the same distinct difference in the development of the deposits between the Fore-Sudetic monocline and West Pomerania area. In the deeper part of the basin, the limestone and limestone-clay deposits with ceratite fauna pass northwards into marly-limestone and marly-dolomite deposits, at places revealing anhydrite nests, and brown-red tint of the deposits found in the shallower part of the basin.