Typomorphism of apatites from metamorphic rocks of the Subpolar Urals (basin of the river Kozhim)

The study of apatites from the metamorphic formations of the Subpolar Urals shows that this mineral can be used as an indicator of the conditions of rock metamorphism. According to the typomorphic features of apatites, one can judge not only the similarity or difference in the degree of metamorphism of the compared rock associations, but also solve the important problem of separating mono- and polymetamorphic formations, in particular. In order to obtain additional mineralogical criteria for subdivision and correlation of Precambrian metamorphic strata of the Subpolar Urals, a description of accessory apatite from metamorphic rocks of the Nyartin Complex, as well as the Shchokurya and Puiva suites, is given. It is shown that morphological features of crystals, the presence, mineral composition and amount of solid and gas-liquid inclusions, the chemical composition of the mineral itself (strontium content, qualitative composition and REE content), spectroscopic properties can be used as typomorphic features of apatites associated with rock metamorphism. Some typomorphic features of apatites can be associated with granitization processes (small inclusions of monazite along the periphery of apatite grains). The results of the studies confirm the previously obtained data on the belonging of the metamorphic rocks of the Nyartin Complex and the Shchokurya suite to the same structural stage