The effectiveness of highly siliceous rocks in the production of environmentally safe crop production

The article presents the results of studying the influence of copper-contaminated soil (typical medium-loamy chernozem) on the ecological safety of grain and the yield of spring wheat when using high-silicate rock - diatomite as a detoxifier. It was found that when diatomite was introduced into soil contaminated with up to 4 MPC Cu at a dose of 5 t/ha, it completely blocked the negative impact of copper on the formation of spring wheat yield. Contamination of the soil with copper up to 10 MPC Cu was accompanied by its accumulation in the grain above the control by 8-35%. The introduction of diatomite into the soil helped to reduce its accumulation in products by 17-50%. Keywords: SOIL CONTAMINATION WITH COPPER, DIATOMITE, ENVIRONMENTALLY SAFE PRODUCTS

On the possibility of introducing X-ray computed microtomography into the practice of biostratigraphic research

Currently, the techniques applied for extraction and study of conodonts from siliceous rocks are associated with a number of problems. This makes it difficult to solve many problems in the areas of development of the volcanic and volcanic-sedimentary rocks, where cherts, jaspers, and phtanites are the only sedimentary formations for dating these deposits. On X-ray computed microtomography it is possible to avoid some problems to obtain not only excellent 3-D images of conodonts, but sections in any direction too, as well as in video formats. It is shown that similar results are successful under the hollows after the dissolution of the conodonts. There is no problem in application of X-ray microcomputed tomography when conodonts have been already found on the surface or inside of the sample, or if the content of conodonts in the rock is obviously high. In such a case the scanning without preliminary search is ensured. In cases when conodonts are rare and not obvious, it is proposed the following technique of their discovery. The rock sample is cut into plates. The conodonts are search for on the surface of the plates, moistened with a mixture of glycerin and water under a binocular microscope. If it is necessary (when the rock is opaque), the result is checked by a chemical reaction: 5–10 % hydrochloric acid plus 1–2 crystals of ammonium molybdate are put on the surface of the sample. The appearance of a yellow sediment means the presence of phosphorus, to indicate the probability the detected object to be a conodont. Next, the sample should be washed from acid, its size should be decreased. Then the microtomographic study should be performed.

Composition of Oil after Hydrothermal Treatment of Cabonate-Siliceous and Carbonate Domanic Shale Rocks

The hydrocarbon compositions of shale oils, generated from two different lithological–facial Domanic deposits of the Tatarstan Republic (Russia), were studied under hydrothermal impact with 30% of water addition in a 350 °С and CO2 environment. The samples were extracted from carbonate–siliceous rocks of the Semiluky–Mendym deposits of the Berezovskaya area, and carbonate deposits of the Dankovo–Lebedyan horizon of the Zelenogorskaya area of the Romashkino oil field. The distinctive features of rocks are in the composition and content of organic matter (OM), its thermal stability, as well as the structural-group composition of the shale oil products. The hydrothermal treatment of the rock samples increased the content of saturates and decreased the content of aromatics, resins and asphaltenes in the composition of crude oil. The decomposition of the polymer-like kerogen structure and destruction processes of high-molecular compounds, such as resins and asphaltenes, are accompanied with the formation of substances highly rich in carbons—carbenes and carboids. The contents of n-alkanes and acyclic isoprenoids increase in the composition of saturated hydrocarbons. According to the chemical classification of Al. A. Petrov, the character of the molecular mass distribution of such substances corresponds to oil type A1, which is considered paraffinic. The contents of dibenzothiophene, naphthalene and phenanthrene are increased in the composition of aromatic hydrocarbons, while the contents of tri-methyl-alkyl-benzene and benzothiophene are decreased. The increase in the aryl isoprenoid ratio (AIR = С13–С17/С18–С22) and maturity parameter (4-MDBT/1-MDBT) under the influences of hydrothermal factors indicates the increasing thermal maturity degree of the hydrocarbon system. The differences in the distribution behavior of saturated and aromatic hydrocarbons—biomarkers in rocks of various lithological-facies types, which are reasoned by different conditions of initial organic matter transformation as well as under the impact of hydrothermal factors—were revealed.

THE PALEOARCHEAN (3.3 Ga) AND MESOARCHEAN (3.0 Ga) TTGs OF THE WESTERN AZOV AREA, THE UKRAINIAN SHIELD

A large anticline structure that includes the West Azov and Remivka blocks occurs in the western part of the Azov Domain of the Ukrainian Shield. These blocks are composed of rocks of the Mesoarchean (3.2-3.0 Ga) granite-greenstone association and relics of an older basement. The anticline is divided into two parts by the Bilotserkivka structure of sub-latitudinal strike; the northern part includes the Huliaipole and Remivka blocks, and the southern part is comprised of the Saltycha anticline. The Archean plagiogranitoids of the West Azov underwent intense dislocation metamorphism during the Paleoproterozoic. In many areas they were transformed into plagioclase gneisses that were attributed to the Paleoarchean “Kainkulak thickness” of the Azov Series. Detailed geological-structural and geochronological studies are required to define the age of these gneisses.We have chosen two areas for our studies: the Lantsevo anticline within the Bilotserkivka structure, and the Ivanivka area in the eastern part of the Saltycha anticline. The Bilotserkivka structure is composed of rocks of the Central Azov Series and highly deformed Archean formations. We have dated plagiogneisses of the Lantsevo anticline. These rocks contain large relics of metamorphic rocks of unknown age, including two-pyroxene and pyroxene crystalline schists, and pyroxenemagnetite quartzites (BIF). In terms of chemical composition, two-pyroxene crystalline schists correspond to tholeiitic basalts and basaltic komatiites. Ferruginous-siliceous rocks belong to the Algoma type typical for the Archean greenstone belts. Biotite gneisses are similar to the medium-pressure tonalite-trondhjemite-granodiorite rocks (TTGs). The U-Pb age of zircon crystallization from biotite gneisses is 3299 ± 11 Ma. At 30 km in the western part of the Bilotserkivka structure, we have previously identified quartz diorites having an age of 3297 ± 22 Ma. In terms of geochemical characteristics, they correspond to low-pressure TTGs. These data show that the Bilotserkivka structure is a block representing an ancient basement. In the Ivanivka area in the eastern part of the Saltycha anticline, the strike of the Archean rocks was reorientated from northwestern to latitudinal. The studied dislocated trondhjemites of the Ivanivka area correspond to TTGs in terms of the geochemical characteristics. They contain numerous relics of highly altered amphibolites. The U-Pb age of zircon crystallization from trondhjemite is 3013 ± 15 Ma. These rocks are of the same age as TTGs of the Shevchenko Complex cutting through the sedimentary-volcanogenic rocks of the greenstone structures of the Azov Domain. They share age and geochemical characteristics with biotite and amphibole-biotite gneisses of the “Kainkulak thickness” in Zrazkove village located at the Mokra Konka river (3.1-3.0 Ga) and with biotite gneisses in the lower reaches of the Kainkulak river (2.92 Ga). Thus, gneisses of the “Kainkulak thickness” in fact represent the Mesoarchean TTGs of the Shevchenko Complex, which were transformed in the Paleoproterozoic time due to the dislocation metamorphism. Late Paleoarchean (3.3 Ga) tonalites are known in the West Azov and the KMA domains; they probably also occur in the basement of the Middle Dnieper domains, where detrital zircons of this age have been reported. These data allow us to conclude the existence of a large Late Paleoarchean (3.3 Ga) protocraton, in which the Mesoarchean (3.2-3.0 Ga) greenstone belts and TTGs of the eastern part of the Ukrainian Shield and the KMA Domain were formed.

Virus-Like Microfossils in the 1.64 Ga Siliceous Rocks From Hogland Island, Russia

Several varieties of virus-like microfossils, morphologically similar to modern giant viruses of the Mimiviridae family, have been identified in microquartzites in the 1.64 Ga volcanogenic-sedimentary strata in Hogland Island in the Gulf of Finland, Russia. Microquartzites contain graphite enriched in a light carbon isotope 12С, as is typical for the rocks forming with participation of living matter. Abundant remains of silificated and ferruginizated microfossils of planktonic microorganisms and virus-like structures were found in fragments of silificated biofilms. However, virus-like microfossils exceed modern giant viruses in linear dimensions by a factor of a thousand or more (Belyaev, 2018; 2019; Belyaev, Yukhalin, 2021) and contain structures similar to eukaryotic nuclei. In addition, data were obtained that can be interpreted as a fact of parasitic relationships of virus-like formations with microfossils of amoeba-like microorganisms. Inside, and in the immediate surroundings of some virus-like structures, small oval zonal formations occur, which, possibly, represent silificated viral particles, the most ancient obligate super parasites similar to "satellite" virophages in mimiviruses (La Scola, et al., 2008). Apatite grains found in the mineralized cytoplasm and nuclei of virus-like microfossils, most likely, crystallized from phosphoric acid residues of decayed nucleotides. This allowed for the first time to roughly estimate the size of the genomes of the most ancient virus-like structures, which exceeded the genomes of modern giant viruses and unicellular organisms by a factor of thousands (Belyaev, Yukhalin, 2021). The genome masses of eukaryotic microfossils and virus-like structures were also estimated following the principle of genomic-nuclear proportionality, according to which the molecular weights of genomes are directly proportional to the size of the nuclei. In this case, the size of genomes of virus-like structures estimated both form the enclosed apatite grains and the size of nuclei, averaged tens of thousands of picograms and, thus, could contain tens of thousands billions of base pairs. It is assumed that microfossils of virus-like structures from the group of unclear systematic position Dinoviridae Incertae sedis were representatives of the extinct family of unicellular facultative parasites or were the ancestors of giant viruses of the Mimiviridae family.

An Early Holocene Lithic Assemblage from Dibé Rockshelter, South-Central Ethiopia

The dearth of securely dated assemblages in the Horn of Africa limits a comprehensive understanding of human adaptation across the Early Holocene. This paper presents results from initial analyses of lithic material from Dibé rockshelter in the Arsi lowlands, Ethiopia. Radiocarbon dates confirm occupation of Dibé rockshelter by hunter-gatherers directly following improved climatic conditions marking the onset of the Holocene. Microliths dominate both the surface and excavated sub-assemblages. Micro-burins and Levallois items are present, although more frequent as surface finds. Regionally available siliceous rocks were extensively exploited, with greater variety in the older occupation layers signifying differential access to raw material sources and/or wider foraging ranges. Largely similar reduction patterns and toolkits across the sampled sequence imply continuity in lithic tradition. This, coupled with the total absence of finds commonly associated with early food production, suggests that Dibé was abandoned during one of the abrupt arid episodes of the Early/Mid-Holocene.

Organic biomorphs may be better preserved than microorganisms in early Earth sediments

The Precambrian rock record contains numerous examples of microscopic organic filaments and spheres, commonly interpreted as fossil microorganisms. Microfossils are among the oldest traces of life on Earth, making their correct identification crucial to our understanding of early evolution. Yet, spherical and filamentous microscopic objects composed of organic carbon and sulfur can form in the abiogenic reaction of sulfide with organic compounds. Termed organic biomorphs, these objects form under geochemical conditions relevant to the sulfidic environments of early Earth. Furthermore, they adopt a diversity of morphologies that closely mimic a number of microfossil examples from the Precambrian record. Here, we tested the potential for organic biomorphs to be preserved in cherts; i.e., siliceous rocks hosting abundant microbial fossils. We performed experimental silicification of the biomorphs along with the sulfur bacterium Thiothrix. We show that the original morphologies of the biomorphs are well preserved through encrustation by nano-colloidal silica, while the shapes of Thiothrix cells degrade. Sulfur diffuses from the interior of both biomorphs and Thiothrix during silicification, leaving behind empty organic envelopes. Although the organic composition of the biomorphs differs from that of Thiothrix cells, both types of objects present similar nitrogen/carbon ratios after silicification. During silicification, sulfur accumulates along the organic envelopes of the biomorphs, which may promote sulfurization and preservation through diagenesis. Organic biomorphs possessing morphological and chemical characteristics of microfossils may thus be an important component in Precambrian cherts, challenging our understanding of the early life record.