Petrogenetic Factors of Formation of Volcanic Rocks of the Yakushiv Unit Rocks of the Volyn Series Continental Flood Basalts of the Volyn-polissya Depression
Year: 2026
Type: article
Abstract: Emphasis is placed on the petrogenetic factors of the formation of volcanic rocks of the Yakushiv Unit Rocks (Yakushiv Strata) (V1 jk) of the Volyn series continental flood basalts of the Volyn-Polissya depression on the basis of fluid-liquid immiscibility interaction and the direct influence of liquidation qualities on the separation of ore matter at the initial stages of the magmatic stage in connection with copper content. They are based on the results of comprehensive studies of complete sections of the Yakushiv Unit Rocks to study the spatial distribution and mineral composition, identify petrographic and petrochemical features and practical significance of the rocks of this stratified unit. The thickness and paleorelief were analyzed based on sections from numerous boreholes that penetrated the Yakushiv deposits in areas of their greatest extent, and important structural features were identified both vertically and laterally. For clarity, maps were constructed showing the thickness and paleosurface relief of the Yakushiv unit rocks, particularly in the areas of the settlements of Ratne and Kamin-Kashyrskyi. Based on the data of petrographic study of the sections of the Yakushiv deposits, there are grounds to believe that they were formed under the influence of fluid-liquid immiscibility interactions, similar to the formation conditions of the Luchychi suite of the continental flood basalts of Western Volyn. Petrochemical parameters indicate that the rocks of the Yakushiv unit belong to the low- to moderately alumina-bearing sodium and potassium–sodium series; according to the femicity coefficient, the unit is melano- to mesocratic; the fractionation (iron enrichment) coefficient ranges from 57.39 to 84.74 wt. %, and the total magnesianity is 55.78–90.23 wt. %. Analysis of the AFM classification diagram shows that differentiation of the basaltic magma proceeded incompletely, with a slight tendency for volcanic evolution from calc-alkaline rocks of basic composition toward tholeiitic ones, accompanied by iron accumulation in the residual melts of the Yakushiv unit rocks. The copper content in the studied rocks is characterized by relatively low values (50–560 g/t), which may indicate uncertain prospects of the Yakushiv unit for copper mineralization and necessitates further targeted studies.
Source: Geological Journal
Authors: N.V. Batsevych, I.M. Naumko, Yu.I. Fedoryshyn
Language: English
Subfield: Geochemistry and Petrology
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: diamond
OpenAlex ID: W7220471815