O niektórych spornych problemach w geologii Sudetów

Abstract

ON SOME CONTROVERSIAL PROBLEMS IN THE GEOLOGY OF SUDETESSummaryThe author discusses some inconformities in the opinions on the geological structure of the Sudetes emphasizing that 1 – lack or scarcity of appropriate evidence materials, and 2 – false methodical principles are the main causes of these inconformities.These remarks concern numerous papers by J. Oberc, mainly, however, the publications distinguished in the references cited (J. Oberc 1960a, 1960b, 1961, 1956a, 1966b, 1968, 1971). J. Oberc discusses granitization processes of some sequences of the Sudetic metamorphicum, without appropriate petrological studies, particularly microscope studies. Chronostratigraphical division of some palaeontologically silent series is based by him only on lithological comparisons and on the degree of development of regional metamorphosis, and the results obtained are 1thought by him to be entirely unquestionable. Sometimes, the author mentioned above defines the age of rocks in a way different from that so far accepted, giving no arguments to justify his new conception.He accepts without any reserves the existence of the Early and Late Assyntian foldings in the Sudetic series, regarding them as Proterozoic, although the age of these series has not so far been proved, like the age of the deformations in them. J. Oberc precisely determines the age of the linear mesostructures in the Sudetic metamorphic sequences of problematical age, once more giving no arguments to support his theses. One cannot agree also with J. Oberc's opinion as to the Pleistocene varved clays of the Sudetes, referred by him to the Upper Miocene, only because these clays include Upper Miocene microflora and Hystrix (J. Oberc, 1969).The floristic elements mentioned above are redeposited and occur in varved clays also in other areas of Poland, being found in the Pleistocene deposits in other countries, too. M. B. Davis describes them from Massachusetts (1961).It is worth emphasizing here that in the vicinity of Jelenia Góra Z. Jaworska (1971) has found this microflora not only in varved clays, but also in boulder clays that include crystalline Scandinavian materials. At Bolków, the Tertiary microflora and Hystrix have been found in the Pleistocene ice-marginal lake deposits mixed with small blocks of the Scandinavian crystalline area, and with flints dragged by inland ice from the Polish Lowland area.J. Oberc and S. Dyjor (1968), based on their unjust opinion tending to refer the Pleistocene varved clays of the Sudetes to the Upper Miocene deposits of marine origin, have worked out a new conception of the young tectonic movements in the Sudetes area. However, this conception must be rejected, since it is based on the false interpretation of the deposits, no doubt of Pleistocene age.