SEDIMENTATION AND POST-SEDIMENTATION FACTORS OF THE FORMATION OF MINERAL AND ELEMENT ASSOCIATIONS IN THE COAL-BEARING MASSIVES OF THE DONBAS

Abstract

The sedimentation and post-sedimentation factors of formation of coal-bearing formations played a leading role in their accumulation and enrichment with individual chemical elements. Recently, much attention has been paid to the possibilities of developing coal deposits as complex deposits. Coal, in addition to organic substances, always contains inorganic components as impurities. The study of mineral-elemental associations is important for determining the processes that contributed to the formation of coal massifs and the changes that occurred in the post-formation period. In the specified coal-mining areas, the selected samples for mineral neoplasms bear traces of high-temperature exposure, which are expressed in the form of dolomitization of limestones, intensive ironization (formation of iron oxides and sulfides), recrystallization of shell carbonates, and fossilization of fragments of plant remains. The magmothermal processes that began with the formation of morphostructures and the formation of conditions for peat accumulation were activated in the post-Carboniferous hydrothermal manifestations in the stratum of the coal-bearing Middle Carboniferous massif, which manifested themselves in the form of significant mineral neoplasms, most clearly represented by sulphide mineralization. Intense sulphide mineralization can be traced in the samples, sections and crosssections with distinct replacement of organic residues by pyrite. The processes of intense mineralization, expressed in the change in the composition of the sandstones of the dislocated bottom of the coal seams, represent later events in geological time, which significantly lag behind the tectonic and tectono-magmatic transformations of the earth’s surface under the peat accumulation basins of the Middle Carb oniferous. The mineralogical and lithological factor caused by the manifestations of certain paragenetic mineral associations makes it possible to correlate coal seams according to the degree of coalification and identify marking horizons. The modern redistribution of chemical elements in the carbonaceous massif is mainly represented by carbonates and sulfates, which are recorded as neoplasms in closed workings.