TO THE QUESTION OF THE GENESIS OF THE LIMESTONE OF THE GUIDIRIM AND SEVERIN DEPOSITS

Problem Statement and Purpose. In Transnistria, the deposits of Sarmatian-age limestone are explored and exploited. These minerals are used as raw materials for cement production, as well as for the production of buta and rubble. The issues of genesis and facial transitions of these deposits remain under-studied.Data & Methods. The purpose of this work is to determine the genetic affiliation of the limestone deposits of the Gidirim and Severin deposits on the basis of facial and chemical analysis. The materials of the research are the limestones of two deposits of Transnistria. The object is the limestone of the Sarmatian age of the deposits of Transnistria. The subject of the study is the lithological and paleontological characteristic, the chemical composition of these limestones. Research methods: topical; biofacial, computer processing with GIS – programs; Laboratory quality diagnostics, chemical and physical-chemical methods of quantifying the main components of carbonate rocks.Results. The geological conditions of the Severin and Gidirim deposits were studied, and the place of productive layers of deposits in the stratigraphic scheme of Transnistria was determined on the basis of the lithological and paleontological characteristics of the rocks. Limestones mined at the Gidirim field belong to the May Day retinue, and the limestone of Severinovsky belongs to the Bessarabian reefs. Chemical analysis of limestone samples extracted from the deposits was carried out and differences in the chemical composition of the limestone of these deposits were determined. The limestone deposits in the content of calcium carbonate are clean. The concentration of silicon dioxide in the samples of the Severin field is higher than in the samples of the Giderim field, the content of one-and-a-half oxides, on the contrary, in Severinovka – 0.68%, in samples of the Giderim field – 1.04%. Analysis of the lithological composition and fauna of limestones has made it possible to distinguish within the Middle-Sarmatian basin of sedimentopulation: (a) accumulation of biogenic-chemogenic limestone of the near shelf, b) biogenic precipitation of the transition zone (reefs), c) silicate-terrigenous formations of the far shelf. The variety of phased conditions in the basin is associated with the position of the coastline and the inflection of the bottom on the boundary of the near and far shelf. The limestone of the studied deposits was formed in two different facial environments: the chemogenic-carbonate and the transient, which is associated with the formation of a strip of Bessarabian reefs. The study of paleontological residues, lithology and chemical composition of rhypogenic limestone showed the autonomy of this environment, as it has features of sedimentogenesis and near and far shelf.