LITHOLOGICAL AND GEOCHEMICAL FEATURES AND CONDITIONS OF FORMATION OF JURASSIC ROCKS OF YIGNALI-DEBINSKY SYNCLINORIUM

As a result of the analysis of the material composition, generalization and interpretation of geochemical data, some features of the formation of Jurassic sedimentary rocks on the territory of the Inyali-Debinsky synclinorium (Debinsky zone) have been revealed. The chemical composition of the rocks is normally alkaline with a predominance of potassium type. They have a high degree of weathering. The enrichment of Au, Ag, Sc, V, Cr, As, Sb, Cs, and EPG rocks has been established in comparison with their average contents in the upper crust. In the Buchennachskaya Formation sediments (the zone associated with faults), increased concentrations of Ni, Co and W are noted, with a decrease in Au contents. High total concentrations of REE, a bright manifestation of Eu/Eu*, the absence or slight anomaly of Ce/Ce* have been established, all this reflects that precipitation was formed in marginal continental environments. Paleogeodynamic interpretation of the totality of the geochemical data obtained indicates that sedimentation occurred in relatively shallow water conditions, warm climate in an oxide environment. The feeding area that supplied the detrital material to the sedimentation basin could be the Uda-Murgal volcanic arc, composed of rocks of basic and medium composition.