ON THE HORNBLENDE GRANITES OF THE SISYA MASSIF (NORTHERN URALS)
The mineralogical-petrogeochemical characteristics of the Upper Riphean hornblende granites composing the main part of the Syisinskii massif in the paleo-continental sector of the Circumpolar Urals are presented. According to the chemistry, the hornblende granites belong to the normally alkaline, moderately potassium rocks with somewhat increased alumina content. The leading mineral paragenesis of hornblende granites and the normative index of femininity testify to the belonging of granitoids to the salic family. The geodynamic nature of the formation of acidic plutonic rocks is characterized by marginal-continental and island-arc conditions. Based on the radiological dating of rocks (U-Pb by the zircon method) and geodynamic conditions, one can speak of the relict manifestation of the island's magma-tism in the late Riphean.