Wiek bezwzględny K-Ar granitoidów masywu Karkonoszy

Abstract

K-Ar ABSOLUTE AGE OF THE KARKONOSZE MASSIF GRANITOIDS

Summary 

K-Ar absolute age determinations were carried out on 13 samples of various petrographic types of granites and 3 aplite samples from the granitoid Karkonosze massif (Lower Silesia). The results fall within the range of 294·10⁶ to 307·10⁶ years for the granites and of 294·10⁶ to 304·10⁶ years for the aplites. The positive systematic error as found by isochron method is 1 per cent. According to the time scale the isochron age of the granites - 299·10⁶ and of the aplites 295·10⁶ years corresponds to the Upper Westphalian and it is related to the Asturian phase of the Variscan orogeny.