On the origin and morphology of Z-shaped splitting of coal deposits (on the example of Eastern Donbass)

Abstract

The article is dedicated to the identification of the morphology and origin of unique coal-bearing structures common in many coal regions of the world - Z-shaped splitting of coal deposits, first discovered by the author in the Eastern Donbass. The relevance of the work is determined by the need to develop the scientific foundations of coal accumulation to determine the industrial value and mineragenic prospects of the territories. Aim. Improvement of the theory of coal accumulation and primary structure formation in sedimentary formations in general. Methods. Material-structural analysis of intersecting geological sections of the coal-bearing territory of the western part of the Eastern Donbass using well-known lithological-structural methods, comparison of the identified Z-object with similar structures of other coal regions and hypotheses about the formation of Z-splits. Results. The first Z-shaped splitting of a coal deposit in the Eastern Donbas was discovered and investigated. The k2n deposit of the Kamenskaya suite C25 of the Carboniferous system near the town of Krasny Sulin is asymmetric in section and plan. The height of the Z-object is the first tens of meters, the area is many tens of km2, and the length from north to south is 20 km wide. The object has a coal base and a vault in plan, their conjugation with a carbon connection. The Z-shape of the object appears in submeridional sections. Unique is the one-sided - from the west - closed connection, the presence of coal bundles-bridges that did not develop before the connection. The stages in the formation of the object are revealed. On a specific example of the conditions for the development of Z-objects: the transverse frontal supply of large balanced portions of mainly plant or plant-mineral material in different parts of the territory from different mineral sediments with a partial entry of the tongue onto one of them covered with a source coal mass. Violation of the conditions leads to a deviation of the structure from the typical one or to the termination of its formation. The mechanism of material receipt is the spill of the paleodelta arms. One-sided closedness of the connection is in terms of providing local flows of mineral material. The sedimentation niche was created by the processes of tectonic relative subsidence of additional areas of the territory. The investigated structure arose under the conditions of a combination of tectonic and sedimentation prerequisites; the main contribution to its formation was the activity of the paleochannels. In this regard, the structure is classified as an accumulative type. Examples of other Z - objects are given. Z-structures are developed at various levels. Research results are of significance for different regions of coal accumulation and solution of general sedimentation issues.