Uwagi o granulitach z okolic Zagórza ŚIąskiego i Bystrzycy Górnej (Góry Sowie)

Abstract

NOTES ON GRANULITES FROM VICINITY OF ZAGÓRZE ŚLĄSKIE AND BYSTRZYCA GÓRNA (SOWIE MOUNTAlNS)The authors have investigated, as to their petrography and chemical properties, the granulites occurring near Zagórze Śląskie,and Bystrzyca Górna in the Sowie Mountains (Eulengebirge) in Lower Silesia (Fig. 1). They carried out 6 chemical analyses (Table 2) and interpreted them. On the basis they reached the following conclusions:1. The granulites represent typical rocks·of a granulite facies with a mineral assemblage characteristic for this facies, comprising: quaritz - pIagioclase - garnet - disthene.2. The granulites disclos a chemical character similar to rocks saturated with alumina; the excess of this substances in evidence as disthene crystallization.3. The granulites are featured by a streaky and thin-Iamellated arrangement of its components. The macroscopically distinguished varieties, a light and a dark one, do not differ in a fundamental manner.4. The enrichment of the granulites in biotite and plagioclase, with their simultaneous impoverishment in garnet and potassium feldspar, indicates a transition type of rock from granulites to·gneisses.On the basis of microscope observations, especially of the development and the behaviour of the individual minerals, the author established the succession in the formation of the mineral assemblages within the granulites, as has been presented in Table 5In view of the similarity in mineral composition between paragneisses and granulites it may be assumed that both were produced from same rock material - thus that they are paragranulites.