Przyczyny zmienności ichtiofauny z serii menilitowo-krośnieńskiej Karpat

Abstract

THE REASONS OF CHANGING OF ICHTHYOFAUNA FROM THE CARPATHIAN MENILITE-KROSNO SERIES

Summary

An attempt is made to evaluate changes in fish association found to occur in the Menilite-Krosno Series of the Flysch Carpathians, in the light of the conditions under which the Carpathian fauna has lived and developed. The authors ascertain that the differentiation within the shallow-water and deep-water fish associations, demonstrated using statistical methods, is a result mainly of changes in time. The influence of time upon the changes of the Carpathian ichthyofauna can be observed even for the time intervals represented by deposits several metres in thickness only. There is discussed also the influence of a lot of factors governing in the environment, e.g. water temperature, salinity, gas content, depth of basin, marine currents, a.o. on the ancient biocenoses on the one hand and on the possibility of occurrence of taphonomic changes in the fossil associations (mainly due to decomposition of fish bodies before covering them with the sediments), on the other. Moreover, the authors state that such a complex picture of the reasons of changes in the Carpathian ichthyofauna results not only from the evolution of the individual fish genera or fish species, but also from the changes in the Carpathian basin. So far only the influence of factors important berely in the basin has been demonstrated (e.g. changes in depth), the influence of other factors requires additional studies. The knowledge of such kinds of relations allows not only the stratigraphy of the Menilite-Krosno Series to be explained, but also the changes in the environment within the Carpathian basin to be interpreted more properly.