Petrograficzne spostrzeżenia nad głazem narzutowym Instytutu Geologicznego

Authors

  • Olech Juskowiak
  • Wacław Ryka

Abstract

SOME PETROGRAPHIC REMARKS ON THE ERRATIC BLOCK OF THE GEOLOGICAL INSTITUTE Summary An erratic block situated in front of the building of the Geological Institute is here described. Microscopic investigations showed, that the rock is a biotite-gneiss of mineral content characteristic for granodiorite. Dark inclusions of amphibolite are encountered. Chemically this rock corresponds to granodiorite or tonalite and shows close resemblance to the gneiss from Kumlinge near Äland. Petrotectonic diagram shows that formerly partial orientation of quartz existed in the rock.

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Issue

Vol. 8 No. 1 (1960)

Section

Geochemia, mineralogia, petrologia