PALEOGEODYNAMICAL RECONSTRUCTIONS AND MINERAGENY OF EARLY-JURASSIC BASALT-ULTRABASITIC FIAGDONSKIY COMPLEX (REPUBLIC NORTHERN OSSETIA-ALANIA, CAUCASUS, RF) ON PETROCHEMICAL, GEOCHEMICAL AND ISOTOPIC DATA

Abstract

The firstly obtained isotope-geochemical data, allows to specify the geodynamics situation in the course of origin of Fiagdon complex (FC) rocks are reported in this article. Early Alpine magmatic complexes, which have been investigated during middle-and end of XX century, were not described by modern isotope-geochemical data. This flaw was supply by on principle new data obtained, on base of which the following conclusions were done: - on the diagnostic diagrams the rocks of FC are concentrated in the fields of basalts of MORB, marginal sea or in zone of overlapping fields basalts MORB and IAT; - comparison of multielements spectrums and spectrums of distribution of REE with N-MORB standart, shown its closeness to tholeitic basalt of the back arc basins, which are intermediate between МОRВ and IAT; - value of 87Sr / 86Sr in basalts and picrites of FC are vary in the range from 0,7038 to 0,7057 and correlated with basalts of ensimatical island arc and marginal sea; - geodynamics conditions of origin of FC rocks are correspond as suprasubduction zone; The radically increased content of gold (from 0,2 tо 3-7 ppm) in serpentinite with process of listvenitization alteration suggests that a new for the Great Caucasus gold-listvenitical type with scheelite of ore mineralization was revealed.