Reconstruction of the conditions for the formation of red-colored sandstones of the Tersky coast based on a comparative analysis of the structure of ancient and modern deposits (Kola Peninsula)

Abstract

The paper presents the results of studying the Riphean red-colored sandstones of the Tersky coast of the White Sea. 21 structural elements characterizing the conditions of rock formation have been considered, including 15 ancient and 6 modern deposits. Observations were carried out for 10 years in two areas of the White Sea coast. The purpose of the research is to establish the reasons for the absence of organic matter, the origin of the hematite admixture in the Riphean sandstones, and to assess the climatic conditions during their formation. These issues are key to identifying the Proterozoic red formation. The data have shown that some rock structures are similar in ancient and modern deposits. Such structures include, for example, wave ripples repeating in detail the dimension, shape, and orientation in both epochs, and therefore can be used to assess ancient marine sedimentation conditions. However, most of the structures testify to fundamental differences in the conditions of rock formation. It has been established that takyrs were systematically formed in ancient rocks and hematite was deposited, which indicates the arid climate in the Riphean and the specific composition of sea water. The most important difference between ancient deposits is the absence of fauna and flora in them.