Analiza porównawcza ramienionogów z utworów kambru Gór Świętokrzyskich i platformy prekambryjskiej w Polsce

Abstract

COMPARISON ANALYSIS OF BRACHIOPODS FROM THE CAMBRIAN DEPOSITS OF THE HOLY CROSS MOUNTAINS Summary Studies of brachiopods from the Cambrian deposits of the Holy Cross Mountains (9) supplied results other than that ones the author has got from Polish part of the Precambrian Platform (7, 8). Although so close location of both areas the brachiopod assemblages differed with taxonomic content, including significantly small number of common species. They documented two various subprovinces within Atlantic-Baltic province. The brachiopod assemblages from the Precambrian Platform are also differentiated but in general the fauna character is the same. The recent compositions of brachiopod faunas from the Precambrian Platform in Poland and from the Holy Cross Mts were shown (Fig., Table). Brachiopods form three distinctly different assemblages, characteristic for Lower, Middle and Upper Cambrian. Some species among them are of index type, with narrow vertical range but also occur the long-term forms. Differences in the fauna character resulted from different facies-environmental conditions within primary basins. Epicontinental basin of the Precambrian Platform had been directly connected with Scadinavian area that was indicated by large number of common brachiopod taxones. The Cambrian deposits from the Holy Cross Mts are of geosyncline type, with other facies development and large thickness. Among brachiopods are endemic species, and species known from Wales and Atlantic coasts of Canada. Genus Trematobulus Matthew is noticed also from Bochemia and Mediterranean areas. Contribution of Scandinavian forms, especially after the Lower Cambrian Cambrian, is small. Brachiopods studies confirmed conclusions of J. Czarnocki (4), who as a first indicated the separate character of the Cambrian from the Holy Cross Mts and Scandinavia. Paleomagnetic studies of the Cambrian from the Precambrian Platform and southern part of the Holy Cross Mts (16, 17) indicated the different paleolatitude of these areas. The question is: were that environmental differences the only one barrier, preventing fauna migration between adjacent areas or such fauna difference resulted from geotectonic reasons - it means that discussed regions had not adjoined during Cambrian (after Lower Cambrian?) period.