Łupki krystaliczne pasma Krowiarek w Górach Kłodzkich
Abstract
Cristalline schists in the Krowiarki range of the Kłodzko Mts.
Abstract
The present paper gives the petrographic and chemical characteristics of the crystal line schists in the Krowiarki range belonging to the so called Stronie series. Petrographic investigations have shown that, in addition to regional metamorphism, the rocks in that range had also been subjected to selective metasomatic feldspathization. The successive phases of this process, first plagioclasic and subsequently microclinic in character, led to the formation of a rich and well differentiated assemblage of paragneissic rocks consisting of the porphyroblastic-, plagioclasic-, albitic-, plagioclase-microclinic and syenitoid varieties, also of omicroclinic quartzite gneisses. Three sets of rocks have been distinguished among the just mentioned varieties of paragneisses. The first consists of rocks that have been enriched only in plagioclase, the second shows a predominance of microcline, the third where the amount of plagioclase balances that of microcline. Plagioclase developed in the paragneisses mainly at the expense of micas, partly at that of quartz. It is not, however, excluded that some part of it derives from the original sedimentary material. Microcline, which owes its origin to feldspathization, develops at the expense of the older generation of plagioclase and by replacing quartz.
Besides the schistose-paragneissic assemblage the rock material from the Krowiarki range has been found to contain a group of rocks other than paragneisses. It consists of graphite quartzites and quartzites, amphibolites and marbles. Metasoimatic feldspathization has affected them but 'Slightly, while the mineral composition of marbles and graphite-bearing rocks has not been altered at all throughout the period of metamorphism.