Wizeńskie wapienie w epimetamorficznym kompleksie Gór Kaczawskich (Sudety)
Abstract
Visean limestones in the metamorphic complex of the Kaczawa Mts. (Sudetes)
In the western part of the Kaczawa Mts. im the vicinity of Lubań Śląski and Gryfów Śląski (Fig. 1) there occur „lenses” of limestones within epimetamarphic Paleozoic rooks which untill now, not have been paleontologically dated. From indirect evidence, Schwarzbach (1934, 1936, 1939) argued that the limestones outcropping along the right ibank of the Gozdnica brook, north Lubań, were of Lower Carboniferous age, while those known from Rząsiny, north Gryfów, were Silurian in age. The limestones from the vicinity of Lubań contain a fauna including crinoids, moluscs, snails, and especially, forms belonging to the family Endothyiridae.This fauna may be indicative of Lower Carboniferous age of the deposits, in question (Chorowska, Ozomkowa 1975). Conodonts have been found in the limestones from Rząsiny. On the basis of samples obtained in 1974 it has been established that the limestones originated in the period from Lower Famenian (do II) till Tournaisiam inclusive (Chorowska, Sawicki 1975). Elaboration of a new paleontological material and re-examination of conodonts found earlier resulted in a more precise determination of the Lower Carboniferous age of the Rząsiny Limestones. Thefee originated at least in part, in the Upper Visean. The limestones and shales exposed at Rząsiny form an olisthostromelike body deformed by later tectonic processes. The limestones occur as blocks of various size. Packets up to some tens of centimeters thick, which are of original limestone beds up to 15 cm in thickness are sporadically uncountered. The blocks and bed packets are embedded in a shaly matrix, and streaks and laminae of the slickenslided shales enveloping the limestone blocks are visible in places. These blocks are of one rock-type, a poorly sorted clastic, partly bioclastic limestone, which contains among other clastics, fragments of shale identical with those of matrix. The limestones contain conodont fauna and other organisms, all of which have been crushed. The shales forming the matrix are almost completely devoid of fossils. The samples were taken in four sections of the quarry (Fig. 2) from each block of limestone. In most cases the encountered fauna was sufficient for dating, as shown by the conodont assemblages listed in Tables 1—4. Each table refers to one of the four sections of the quarry sampled in detail (Figs. 3, 4, 5, 6). Assemblages from the samples 27 and 33 (Table 2) containing Gnathodus girtyi girtyi and G. cf. girtyi collinsoni are indicative of the Upper Visean. The species Dollymae hassi, Dollymae sp. B. Voges 1959, Gnathodus texanus, Mestognathus beckmanni and others from the genus Mestognathus as well as Prioniodina subaequalis and Scaliognathus anchoralis occur in the mixed assemblages indicating Visean age most in the cases (diagnostic comodonts are presented in Flatés 3—8). The presence of the Visean limestone in the epimetamorphic complex of the Kaczawa Mts. means that this part of the Vardscam geosyncline has not been folded prior to the Sudetic phase. It should be also noted that the orogenic movements of the Sudetic phase have been also marked in the neighbouring area of Lusatia (Brause, 1967).
In the western part of the Kaczawa Mts. im the vicinity of Lubań Śląski and Gryfów Śląski (Fig. 1) there occur „lenses” of limestones within epimetamarphic Paleozoic rooks which untill now, not have been paleontologically dated. From indirect evidence, Schwarzbach (1934, 1936, 1939) argued that the limestones outcropping along the right ibank of the Gozdnica brook, north Lubań, were of Lower Carboniferous age, while those known from Rząsiny, north Gryfów, were Silurian in age. The limestones from the vicinity of Lubań contain a fauna including crinoids, moluscs, snails, and especially, forms belonging to the family Endothyiridae.This fauna may be indicative of Lower Carboniferous age of the deposits, in question (Chorowska, Ozomkowa 1975). Conodonts have been found in the limestones from Rząsiny. On the basis of samples obtained in 1974 it has been established that the limestones originated in the period from Lower Famenian (do II) till Tournaisiam inclusive (Chorowska, Sawicki 1975). Elaboration of a new paleontological material and re-examination of conodonts found earlier resulted in a more precise determination of the Lower Carboniferous age of the Rząsiny Limestones. Thefee originated at least in part, in the Upper Visean. The limestones and shales exposed at Rząsiny form an olisthostromelike body deformed by later tectonic processes. The limestones occur as blocks of various size. Packets up to some tens of centimeters thick, which are of original limestone beds up to 15 cm in thickness are sporadically uncountered. The blocks and bed packets are embedded in a shaly matrix, and streaks and laminae of the slickenslided shales enveloping the limestone blocks are visible in places. These blocks are of one rock-type, a poorly sorted clastic, partly bioclastic limestone, which contains among other clastics, fragments of shale identical with those of matrix. The limestones contain conodont fauna and other organisms, all of which have been crushed. The shales forming the matrix are almost completely devoid of fossils. The samples were taken in four sections of the quarry (Fig. 2) from each block of limestone. In most cases the encountered fauna was sufficient for dating, as shown by the conodont assemblages listed in Tables 1—4. Each table refers to one of the four sections of the quarry sampled in detail (Figs. 3, 4, 5, 6). Assemblages from the samples 27 and 33 (Table 2) containing Gnathodus girtyi girtyi and G. cf. girtyi collinsoni are indicative of the Upper Visean. The species Dollymae hassi, Dollymae sp. B. Voges 1959, Gnathodus texanus, Mestognathus beckmanni and others from the genus Mestognathus as well as Prioniodina subaequalis and Scaliognathus anchoralis occur in the mixed assemblages indicating Visean age most in the cases (diagnostic comodonts are presented in Flatés 3—8). The presence of the Visean limestone in the epimetamorphic complex of the Kaczawa Mts. means that this part of the Vardscam geosyncline has not been folded prior to the Sudetic phase. It should be also noted that the orogenic movements of the Sudetic phase have been also marked in the neighbouring area of Lusatia (Brause, 1967).