The paper presents the results of studying the development of calcite neoformations on the surfaces of modern buildings within the city of Tyumen. The objects of the study were carbonate crusts and stalactite-like bodies formed on the surfaces of five representative buildings in the city center. Research methods included visual diagnostics, optical microscopy, scanning electron microscopy with energy dispersive X-ray spectroscopy, confocal laser scanning microscopy and semi-quantitative determination of the mineral composition by X-ray diffraction analysis. The results of the study show that calcite is the main component of all carbonate crusts, while other minerals were found in small quantities. The microscopic studies revealed the differences in morphology of crusts developing on horizontal and vertical surfaces. The mycelium of fungi (presumably of the Penicillium group), represented by filamentous and often hollow hyphae covered with calcite, as well as relics of bacterial colonies were found in all studied samples. It was noted that the mycelium forms the structural frame of carbonate crusts and stalactites. Studies have shown that the prokaryotic–eukaryotic communities are responsible for the high rate of the urban speleothem growth and play the main role in calcite precipitation at the initial stages of their development.

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The relevance of the work is due to the need to study ore copper-sulphide deposits in the Urals. Purpose of the work: description of accessory brockite in metasomatites of the Safyanovskoe copper-sulphide deposit. Research methodology: the chemical composition of minerals was determined using the Jeol JSM-6390LV scanning electron microscope with an INCA Energy 450 X-Max 80 energy dispersive attachment from Oxford Instruments (Institute of Geology and Geochemistry of the Ural Branch of the Russian Academy of Sciences, Ekaterinburg). Results and conclusions. For the first time for the Safyanovskoe copper-sulphide deposit (Middle Urals), an aqueous rare earth phosphate of calcium and thorium, brockite, has been determined; it belongs to the group of rhabdophane (Ca,Th,REE)[PO]4 ∙ _H2 O. The mineral is rare for the Urals and was described earlier in granite pegmatites of the Middle and South Urals, as well as in dikes of metaplagiogranites of the Bazhenov ophiolite complex. Brockite was found in the rocky metasomatites of the Safyanovskoe copper-sulphide deposit after crystalline lithoclastic tuff (tuffaceous sandstone) of acid composition. The main mass of the rock consists of quartz, kaolinite (sericite), carbonates (dolomite, Fe-magnesite) with rare inclusions of pyrite. Brockite is found in the dolomite-quartz matrix of the sample in intergrowths with REE-goyazite – strontium aluminophosphate. It is assumed for the Safyanovskoe copper-sulphide deposit that an alumina association with an ore mineral association and rare earth minerals, in particular, REE-alumophosphates and phosphates, will form closely at the same time as the temperature drops and the redox conditions of the mineral formation environment change.

The present paper is aimed at studying hydrophilic and hydrophobic interactions via the modeling behavior of carbonate-clayey soil in a laboratory experiment. The typical aspects of human impact on the biogeochemical processes of natural soils such as decompression, disintegration, hydration and introducing easily oxidized organic matter were simulated. The experimental settings were adjusted regarding common field conditions for the clay near-surface layers in the temperate zone. The model system consisted of a carbonate-clayey soil, filtering water, and a psychrophilic microbial community desorbed from cave calcite formations (speleothems). The carbonate-clayey soil was collected from eluvium on red clay bedrock deposits of the Permian system along the right bank of the Volga River in the Republic of Tatarstan. The microbial community was stimulated with a modified R2A growth medium and inoculated into the clay using ceramic carrier discs. In order to explain the results of the experiment auxiliary materials presented simplified systems of the carbonate clay components were used. Soil properties such as the size distribution of mechanically strong particles and microaggregates, mineral composition, organic matter content, water wettability, and the chemical composition of filtered water were determined. The experiment being carried out during six months showed the appearance of new hydrophobic contacts between soil particles, crystalline cement deposition and the high sensitivity of these processes to microbial activity. The results of the study may help in understanding the processes that occur when foundations for constructions or underground facilities contact microbially produced substances, as well as predicting soil weathering.