This work presents new data on the lithology, paleontology, stratigraphy, and correlation of Jurassic deposits of the Irkutsk coal-bearing basin. According to the detailed analysis of the lithology and paleontology of the reference sections, the Jurassic deposits of the southern part of this basin are subdivided into four formations: Baikal’skaya, Dabatskaya, Cheremkhovskaya, and Prisayanskaya. The Lower Jurassic coarse deposits of the Baikal’skaya Formation are regarded as the most ancient; the Middle Jurassic deposits of the Prisayanskaya Formation are the youngest. The industrial coal-bearing deposits of the Cheremkhovskaya Formation formed in the Early Jurassic, from the Pliensbachian to Toarcian.

The Cenozoic sediments of Lake Baikal penetrated by boreholes and investigated by the manned submersible Pisces, as well as coeval deposits cropping out in beach scarps, recovered by mine workings, and drilled in the coastal zone were the object of this investigation. The main attention was paid to Pleistocene bottom sediments penetrated by Borehole BDP-99-2. The investigations included the detailed analysis of the lithology (grain-size composition, immersion mineralogy of light and heavy fractions, X-ray structural analysis of clayey fraction) and palynological assemblages to specify facies features of Cenozoic sediments, correlate all their known stratigraphic units constituting the sedimentary section of the lake with their analogs in the onshore part of the Baikal rift zone, and compile the composite Cenozoic section. The following features of these sediments are noted: (1) as a whole, Pleistocene sediments are characterized by the hydromica-smectite composition of their clayey fraction with an insignificant share of kaoline; (2) the heavy fraction is dominated by the terrigenous epidote-amphibole association poorly resistant to weathering; (3) Pleistocene sediments of the lake contain siderite, vivianite, pyrite, and goethite concretions and micrometeorites, in addition to well-known ferromanganese nodules; (4) the presence of relict palynomorphs in Pleistocene sediments of Baikal is determined by their erosion from Miocene and Pliocene cavernous clays cropping out on underwater slopes of the Posol’skaya Bank and subsequent reburial along with Pleistocene palynological assemblages.

Pioneer results of the comprehensive analysis of nodules from the Upper Paleozoic coaliferous association and the underlying Middle Paleozoic sequence in the southern Tunguska Basin (Siberian Craton) suggest the following: (1) sediments underlying the coaliferous association contain two (siliceous and carbonate) types of normal nodules and one type of allogenic nodules (redeposited chalcedony nodules in the kaolin-itechalcedony unit of the Beloyarsk Formation); (2) the coaliferous association includes four (calcite, siderite, pyrite, and goethite) types of nodules; (3) each nodule type is confined to a specific genetic type of sediment; e.g., siliceous nodules are confined to lagoonal sediments; calcite nodules, to lacustrine and lacustrine-boggy sediments; siderite nodules, to lacustrine-boggy and boggy sediments; pyrite nodules, to boggy sediments; and goethite nodules, to alluvial sediments; (4) the formation of goethite nodules is mainly related to the erosion and redeposition of siderite nodules; (5) the coefficient of carbon concentration shows a distinct positive correction with the coefficient of nodule content; (6) nodules appeared in the coaliferous association during diagenesis and epigenesis; the calcite and pyrite nodules are enriched in sandy material, as suggested by the high content of insoluble residue; (7) combustion of coal seams promoted the melting of the adjacent siderite nodules and the formation of magnetite ores; consequently, the thermally altered mudstones, siltstones, and sandstones were transformed into a high-quality building material that is used as road fill.

Based on the catastrophic June 28, 2014, Arshan debris flows in the Eastern Sayan Mountains, the structure and lithological composition of the debris are studied and a debris flow defense system is pr

The paper presents the results of a study of epigenetic changes in technogenic-redeposited coal-bearing rocks of Irkutsk and Kuznetsk coal basin spoil heaps (Russia). Hydrocarbon products formed under high-temperature and low-temperature pyrolysis of coal-bearing rocks were studied by using a chromatography-mass spectrometer GCMS-QP2010NC Plus (made by Shimadzu Company). The average temperature of low-temperature natural pyrolysis does not exceed 120 °C, and its average speed is approximately 2 m/year. In this case, three pyrolysis zones gradually built metamorphic rock mass (from bottom to top) are clearly established: heating (focal) activated and enriched. The average temperature of high-temperature pyrolysis reaches 850 °C, and its average speed is approximately 20 m/year. Unlike low-temperature pyrolysis, high-temperature pyrolysis is accompanied by the presence of two major zones (from bottom to top): pyrogenic (focal) and enriched (coke). The chemical composition of the enriched pyrolysis zone was studied in detail. It has been established that hydrocarbon compounds in samples of the pyrolysis zone are presented by six classes: asphaltic-resinous substances; polycyclic aromatic hydrocarbons, heterocyclic compounds, organic sulphur compounds; pyrolytic hydrocarbon and heavy hydrocarbon residue. Quantitative content of hydrocarbon compounds in the analyzed samples varies from 0.35% to 41.88%.