Carbonate Neoformations on Modern Buildings and Engineering Structures in Tyumen City, Russia: Structural Features and Development Factors

Abstract

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.

Ion-Substituted Carbonated Hydroxyapatite Coatings for Model Stone Samples

“…The layer varies between 30-90 μm, which is in good agreement with other literature report [39]. By brushing, the layer is thickened, as SEM images shown (Figure 10a-d).…”

“…The layer thickness of the other consolidants is very thin, between 8-10 μm, this being a possible reason for the low efficacy of them. The layer varies between 30-90 µm, which is in good agreement with other literature report [39]. By brushing, the layer is thickened, as SEM images shown (Figure 10a-d).…”

A Two-Way Avenue of Knowledge: An Editorial for the Special Issue “Geoscience of the Built Environment 2019 Edition”

“…Field observations are a characteristic, distinguishing method in geological studies and previously I have alluded to the example of how Lyell [6] highlighted the importance of field observations in refuting Werner theory about the genesis of igneous rocks. The paper presented in this special issue by Novoselov et al [12] presents extensive field studies asserting the frequency and diversity of carbonate neoformations but goes significantly further with laboratory studies that show how studies in the built environment can contribute to the discussion of some fundamental issues of geosciences (in this case, mineral genesis). The hypothesis proposed by the authors on the biological contribution must be highlighted given the present interest in biomineralization, namely of calcium carbonate.…”

“…Indeed, one can argue that in the same way that there are patterns of speciation specific for organisms in the urban environments [11], there are undesigned crystal-forming processes that could be specific to the urban environment. The interactions between building materials and weathering agents contribute to the formation of products that are chemically and structurally similar to mineral species found outside the built environment, and the paper by Novoselov et al [12] presents a very detailed study of carbonate neoformations. My research has also involved this kind of products and indeed in a 2017 publication [13] based on extensive field observations, we concluded that they were the most extensive alteration feature in recent structures as they can occur in outside and inside places (some underground stations of Lisbon and Porto Metro systems in Portugal present easily observable examples).…”

“…The hypothesis proposed by the authors on the biological contribution must be highlighted given the present interest in biomineralization, namely of calcium carbonate. There is extensive research on fast forming forms of calcium carbonate, precursors of calcite, which can be of interest also in terms of carbon sequestration, and the study of Boch et al [14] showed the fast formation of ikaite in built structures (in conditions with some geochemical affinities with those studied by Novoselov et al [12]). The present year even saw the publication in the journal Science of the proposal of a new hemihydrate calcium carbonate found in laboratory experiments [15].…”