STRUCTURAL-PALEOGEOGRAPHIC AND LITHOLOGICAL- FACIES REGULARITIES OF THE FORMATION OF AMBER- BEARING STRATA AND AMBER DEPOSITS OF THE PRIPYAT OLIGOCENE BASIN

Abstract

The aim of the work is to study the structural-paleographic and lithological-facies regularities of the geological structure of the region and to develop, on their basis, the principles of zoning amber deposits of the Pripyat amber-bearing Oligocene basin. The work used own field and office materials, research by colleagues, fund and published works. Zoning the territory of amber deposits was actively pursued by researchers of the late 20th and early 21st centuries; their works emphasize the need to identify clear criteria for the allocation of amber-bearing subdivisions. The Pripyat Oligocene sedimentary marine basin was formed during the Mezhyhirya epoch, therefore, in accordance with the conducted many years of diverse research, the Mezhyhirya is considered the main stratigraphic level of amber distribution among Paleogene sediments within the Pripyat Depression. The Mezhyhirya level in the western part of the East European Platform has three structural-paleographic regions (SPR), among which the intra- marine and marine marginal-inland are developed in the territory that was studied. Each of the SPR is divided into subregions according to the nature of the internal structure. The performed lithological and facies studies allow us to distinguish a general (transverse) series of glauconite-containing facies of the intermontane terrigenous glauconite Lower Oligocene subformation, which are distributed according to certain facies groups both in the marginal-marine SPR and in the marine marginal-inland SPR.The performed ranking of amber-bearing deposits will facilitate their systematization and improvement of criteria for zoning amber-bearing territories. The amber-bearing nature of a stratum is related to the facies of the deposits and to its specific structural-paleogeographical position within the sedimentary basin. Among the glauconite-containing facies, there are those that are specialized for amber: silty-sandy amber-bearing; sandy-clayey-silty amber-bearing; clayey-silty amber-bearing; clayey amber-bearing. At the same time, the increase in amber-bearing facies is positively correlated with the increase in the clay fraction. The amber content of facies varieties was analyzed by the amount of amber content, it increases with increasing clay fraction. The obtained generalizations of the study were made on new relevant material. They will contribute to the expansion of further prospects for a comprehensive theoretical and practical study of amber-bearing deposits of the region.