Fluids—The Basis for the Formation of Vein-type Mineral Complexes in Sedimentary Coal-bearing Strata
Nataliia Vergelska *
Department of Mining Geoecology, State Institution «Scientific Center of Mining Geology, Geoecology and Infrastructure Development of the National Academy of Sciences of Ukraine», 34 b Akademika Vernadskoho Blvd, Kyiv, 03142, Ukraine.
Viktoriia Vergelska
State Institution «Scientific Center of Mining Geology, Geoecology and Infrastructure Development of the National Academy of Sciences of Ukraine», 34 b Akademika Vernadskoho Blvd, Kyiv, 03142, Ukraine.
Dina Holovchenko
State Institution «Scientific Center of Mining Geology, Geoecology and Infrastructure Development of the National Academy of Sciences of Ukraine», 34 b Akademika Vernadskoho Blvd, Kyiv, 03142, Ukraine.
*Author to whom correspondence should be addressed.
Abstract
The sedimentary strata of the lithosphere are constantly changing under the influence of tectonic deformations, lithogenic processes, and fluid movement. The study of secondary processes in the upper layers of the lithosphere is possible in natural outcrops or man-made engineering structures that expose the sedimentary strata: tunnels, quarries, adits, and mines. In most cases, fluid systems are recorded as fractures or discontinuities, forming a network of vertical, horizontal, or vertical-horizontal—predominantly carbonate—veins.
This study aims to identify the geological processes that contributed to the development of secondary fluid processes and the formation of calcite and quartz-calcite veins in the sedimentary strata of coal basins. Geological studies of calcite and quartz-calcite systems in sedimentary strata, including the possibility of their modern occurrence, were conducted and summarised. Spectral analysis was performed on coal and host rocks containing calcite veins and carbonate formations from mine workings after preparation for laboratory analysis.
The formation of vein-type mineral complexes indicates post-depositional processes involving fluid transport and fracture-filling mechanisms in sedimentary rocks characteristic of the coal-bearing massifs of the Krasnoarmiysk, Dovzhano-Rovenky, Central, and Donetsk-Makiivska coal industrial regions of the Donbas. Calcite inclusions and calcite veins that disrupt the integrity of the coal matrix were also identified in sections m2, m3, m42, l1c, l2, l3, and l4a. Thus, directly or indirectly, the formation of mineral veins in the coal-bearing strata of the Donets Basin influences gas redistribution within the sedimentary strata they alter. Fluid migration continues within the newly formed voids—including those of anthropogenic origin—which are represented by both carbonate formations and gas reservoirs in the coal-bearing massifs. In the Earth’s lithosphere, during fluid migration and conservation, new carbonate mineral systems form that can still be studied today. Given their formation and genesis, tectono-magmatic or post-magmatic processes—including hydrothermal ones—play a leading role.
Keywords: Earth’s lithosphere, fluids, coal basin, calcite and quartz-calcite systems, sedimentary strata