The importance of biological factors in the genesis of the unique niobium and rare-earth ores of the Tomtor deposit, in northwestern Yakutia, is indisputable, but the exact conditions under which these ores formed remain poorly understood. The first micropaleontological study of these ores suggested the major role of benthic cyanobacterial mats developing along the sea coast. The goal of this paper was to scrutinize that hypothesis. Reexamination of archival materials found no clear evidence of the development of benthic cyanobacterial mats. Instead, signs of active development of plankton communities and communities of benthic sediments were found. The new data reconstruct the environment of shallow, sun-warmed waters well suited for algal blooms.

Data indicating the important role of microorganisms in the formation of nodular monazite (NM) (kularite) of the Kular Range, Republic of Sakha (Yakutia), are presented. The NM contains microorganisms (cyanobacteria) replaced by REE-bearing phosphate (monazite) in the form of stromatolitic microedifices, as well as framboidal Fe sulfides in monazite. The Corg isotopic composition of kularite corresponds to biogenic carbon: the δ13С values vary from –22.2 to –22.3‰.

A study of the Tomtor rare-earth-niobium deposit showed the presence of massive accumulations of remains of filamentous and coccoid microorganisms in varying degrees of preservation, lithified by rare-earth phosphate. They resemble modern benthic cyanobacteria.

A nondestructive layer-by-layer elemental and phase analysis of the ferromanganese intact crust (aged about 60 million years), extracted from the 1200-m rise of Magellan Mountains of the Pacific Ocean, has been performed using the X-ray fluorescence and X-ray diffraction methods. The crust morphology was studied using scanning electron microscopy. This analysis made it possible to estimate the contributions of various oceanic sources of iron and manganese to the crusting process and propose a mechanism for its formation.

The Tatarka bauxite deposit on the territory of the Russian Federation was formed as a result of sedimentation of the products of denudated lateritic weathering crusts of amphibolites in contact-karst depressions. Detailed mineralogical studies of bauxites made it possible to reconstruct reliably the conditions for their formation. As it turned out, the initial rocks and rocks, weathered before, have been denudated due to the close location of the areas of alimentation and accumulation. At the same time, chemical processes have been continued in karst depressions. For the first time, the presence of nanoparticles of amorphous aluminum oxide was revealed in contact-karst bauxites. This specific feature of the form of alumina precipitation is associated with the subsequent cessation of lateritization and their attenuation with depth. The presence of amorphous aluminum monohydrate must be taken into account when choosing a scheme for bauxite enrichment.

The results of a long-term electron microscopic study of Kamchatka geyserites are presented showing biological remains of unique preservation and a wide variety of cyanobacteria silicification types. The data obtained made it possible to consider the geyserites of Kamchatka as a model object for bacterial-paleontological studies.

The Khuvsgul phosphorites became the first model object of bacterial paleontology. During their study, techniques were developed for preparing samples for viewing on a scanning electron microscope and for screening the samples for the presence of identified fossil bacteria. Due to the wide variety of fossils found, different forms of bacteria preservation were identified, and the conditions of their formation were explored.

Неразрушающий послойный химический и фазовый анализ железомарганцевой корки (возрастом 60 миллионов лет), извлеченной с глубины 1200 м поднятия Магеллановых гор в Тихом океане, проведен с помощью рентгеновского флуоресцентного и дифракционного методов. Морфология корки изучена с помощью сканирующей электронной микроскопии. Это позволило оценить вклады различных океанических источников железа и марганца в процесс образования корки и предложить механизм ее формирования.

The study of mollusk fauna from the Vendian–Cambrian sections of the Western Mongolia revealed common species of mollusks between the Bayangol Formation of Mongolia and the Nemakit-Daldynian and Tommotian stages of the Siberian Platform. We show that the Cambrian lower boundary (in terms of the General Stratigraphic Chart of Russia) in the Zavkhan structural-facies zone of the Western Mongolia can be recognized in the sections by the first appearance of the following Tommotian species of mollusks, i.e. Watsonella crosbyi Grabau, Bemella jacutica (Missarzhevsky), Aldanella sibirica Parkhaev et Karlova, Merismoconcha tommotica (Zhegallo), Asiapatella undulata (Yu), Pseudoscenella taishirica (Zhegallo), Purella tenuis Zhegallo, and Protoconus orolgainicus (Zhegallo). These species compose the faunal assemblage of the Watsonella crosbyi–Merismoconcha tommotica Zone, which is traced in the middle and upper parts of the Bayangol Formation. Thus, in contrast to previous studies that placed the base of the Cambrian near the base of the Bayangol Formation, we significantly raised the lower boundary of the Cambrian system up to the level of the middle to upper part of the Bayangol Formation.

Biomorphic microstructures of ferromanganese oxide ores are studied, focusing on the issues of types of microstructures, activities of bacterial communities that influence the formation of the structure of oxide ores, and determination of the basis of ferromanganese ore genesis. Ferromanganese oxide ores are a model object of bacterial paleontology for the quality and detail of their study.

The shell microstructure of the rare lingulate genus Praeoehlertella Mergl, 2001 from the Famennian of Kazakhstan is studied. The structure of the shell matrix and the secondary granular layer are studied using scanning electron microscope. Imprints of cells of the inner mantle epithelium are discovered.

The structure and microstructure of the shell matrix of Acrotretella sp. is studied in protegulum (embryonic shells), brephic (juvenile shells), and adult shells. The structure of the secondary layer, represented by interlayers with columnar and spherulitic structures. Wrinkles developed along the shell margins.

A study of previously collected fossils and of new data on Cambrian mollusks from the Bayangol Formation of Western Mongolia (Zavkhan structural-facies zone) revealed a significant similarity in the taxonomic composition of the mollusk assemblages of Western Mongolia and Southern France ( Heraultia Limestone, Marcou Formation, Montagne Noire). In addition to the previously reported four common species ( Latouchella korobkovi (Vostokova, 1962), Protoconus orolgainicus (Zhegallo, 1996), Purella tenuis Zhegallo, 1996, and Watsonella crosbyi Grabau, 1900), we have identified ten more common species for these regions including Auricullina auriculata (Vassiljeva, 1990); Bemella jacutica (Missarzhevsky, 1966); “Calbyella” multicostata Missarzhevsky, 1995; Cambroscutum concameratum Kerber, 1988; Helcionella sp.; Merismoconcha tommotica (Zhegallo, 1996); Obtusoconus amplus (Zhegallo, 1982); Prosinuites tripartitus Kerber, 1988; Purella layracensis (Kerber, 1988); and Securiconus sp. We have to reconsider the existing reconstruction of faunal relations of paleobasins on the western framework of Gondwana in terms of substantiating a close faunal exchange with the Zavkhan terrane, which was during the Early Cambrian a part of the chain of microcontinents located at low latitudes between the Siberian Platform in the west and Gondwana in the east.

The fossils of the genus Yochelcionella Runnegar et Pojeta, 1974 from the Salaanygol and Khairkhan formations of the Zavkhan structural-facies zone were re-studied as a part of the general revision of malacofauna from the Vendian–Lower Cambrian deposits of Western Mongolia. It was found out that studied strata, in addition to the earlier reported species Y. parva Zhegallo, 1996 and Y. crassa Zhegallo, 1996, contain two other forms identified as Y. chinensis Pei, 1985 and Yochelcionella sp. The species Y. chinensis has the widest distribution among representatives of the genus Yochelcionella and can be successfully used to correlate sediments of remote paleobasins. The diagnosis and composition of the genus Yochelcionella are revised, the species Y. chinensis is described.

Background. Phosphatized bacteria of various shapes and numerous structures resulting from their vital activity have been found in the Late Cretaceous (Campanian) of Palmyra phosphorites deposits in Syria. Despite their great importance in the formation of phosphorite deposits, these bacteria have not been previously described in publications on Syrian phosphorites. This fact determines the relevance and originality of this study. Aim. To identify and describe varieties of bacterial microfossils in Syrian phosphorites. Materials and methods. The research material included the authors’ collection of phosphorites from the phosphate layers of the Alsharqiya quarry, thin sections for optical microscopy and samples for electron microscopic analysis. The photos of thin sections were obtained using a MIKMED-5 opticalmicroscope (Russia). A SEM analysis was conducted using a TESCAN VEGA-3, TESCAN VEGA-2 electron microscope (Czech Republic). A semi-quantitative elemental analysis of the sample composition was performed using an EVO-50 Zeiss electron microscope with an INCA Oxford 350 microanalyzer (UK). The samples were sputtered with gold. Results. Five varieties of phosphatized bacteria, and five different structures formed as a result of their vital activity were identified. The internal structure of phosphate grains due to the activity of bacteria was established. Conclusions. In addition to macrobionts (foraminifera, bivalves, bone remains, and other organic remains), a variety of bacteria were involved in the formation of Syrian phosphorites at the stage of sedimentation and diagenesis.

An assemblage of organophosphatic brachiopods of the superfamily Discinoidea are described from the Famennian of the New Siberian Islands. The microstructure of the shell matrix in the genus Opatrilkiella is examined for the first time. Data on the shell microstructure of the genus Orbiculoidea are supplemented, and microornamentation is shown for the first time in the genera Opatrilkiella and Schizobolus .

The organophosphatic brachiopod assemblage from the Famennian deposits of Novosibirsk Islands was described firstly. There is the new information of shell microstructure of the genus Opatrilkiella. It is supplemented information about microornamentation of genera Orbiculoidea and Schizobolus.

The structure and microstructure of the shell substance Acrotretella sp. on the protegulum, brephic and adult shell. The structure of the secondary layer, represented by interlayers with columnar-lamellar and spherulite structures, is characteristic. Wrinkles are developed along the edges of the shell.

Впервые описана колумнарно-пластинчатая микроструктура раковины у Kasagittella sp. (отряд Lingulida, семейство Obolidae King, 1846) из верхнего девона (франские отложения) Усть-Черемшанской структурно-фациальной зоны. Данная микроструктура более характерна для отряда Acrotretida.

The columnar-lamellar microstructure of Kasagittella sp. (order Lingulida, family Obolidae King, 1846) from the Upper Devonian (Frasnian) of the Ust-Cheremshan structural-facies zone is described for the first time. This microstructure is more typical of the order Acrotretida.