Wielostopniowa analiza taksonomiczna w badaniach zespołów otwornic mioceńskich

Stefan Witold Alexandrowicz



The paper presents multistage model of taxonomical analysis enabling interpretation of results of micropaleontological studies and especially differentiation of microfaunal assemblages, estimation of differences between them, arranging the assemblages in a hierarchical system and selection of samples representative of an assemblage. The analysis is carried out in 4 stages (fig. 1). During the first stage representative samples characterized by the least mean values, dSt, are selected using computed taxonomical distances, dSt, between samples in entrance populations (Fig. 2). During the second stage all the samples selected for 12 assemblages analysed are arranged according to their indices dSt. The degree of individuality of the assemblages is subsequently determined by discrimination of Wrocław dendrite and dendrograph (Figs. 3, 4). In the third stage the assemblages are grouped in a unified taxonomic system which makes possible to distinguish three groups of assemblages: Lancendorfian faunal group, benthic faunal group corresponding to Late Badenian cycle in the development of foraminifers and a group of impoverished fauna living under unsuitable paleoecological conditions (Fig. 5). The fourth stage of calculations' is connected with quantitative characterization of differences and similarities between the groups of assemblages and evaluation of internal differentiation of the assemblages on the basis of all the quantitative data (Fig. 6). The studies cast some light on phases of development of microfauna in Badenian sea of the western part of the Carpathian Foredeep. The results obtained indicate a remarkable usefulness of multistage taxonomical analysis in interpretation of results of micropaleontological and, indirectly, mineralogical, petrographical and chemical studies.

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