The zoneblock structure of the lithosphere is represented by a hierarchically organized pattern of stable blocks and mobile zones which border such blocks and contain highly dislocated geological medium (Fig. 1). Today, different specialists adhere to different concepts of blocks and zones, which are two main elements of the lithosphere structure. Differences are most significant in determinations of 'interblock zones' that are named as deformation / destructive / contact / mobile / frac ture zones etc. due to their diversity in different conditions of deformation. One of the most effective approaches to studying the zoneblock structure of the lithosphere is a combination of geological and geophysical studies of interblock zones tectonic features on various scales, which can make it possible to reveal the most common patterns of the interblock zones, general regularities of their development and relationships between the interblock zones.The main objectives of our study were (1) to identify the zoneblock structure of the crust in the southern regions of East Siberia from tectonophysical analysis of geological and geophysical surveys conducted on four different scales along the 500 km long ShertoyKrasny Chikoy transect crossing the marginal segment of the Siberian block, the Baikal rift and the Trans baikalian block (Fig. 2); (2) to clarify structural features of the central part of the Baikal rift (representing the tectonic type of interblock extension zone) by applying new research methods, such as radon emanation survey, to the ShertoyKrasny Chi koy transect and using the previously applied methods, such as magnetotelluric sounding, on a smaller scale; and (3) to study manifestation of interblock zones of various ranks in different geological and geophysical fields, to reveal common specific features of their structural patterns for the upper crust, and to establish regularities of hierarchic and spatial relationships be tween the interblock zones.On the global scale, the object of our study at the ShertoyKrasny Chikoy transect was the Baikal interblock zone (Fig. 2, 15, and 16). On the transregional scale, large fault zones were studied (Fig. 6, 11, and 14). On the regional and local scales, the objects of our study were systems of faults and fractures of various ranks which were active at the late Cenozoic stage of tectogenesis (Fig. 4, and 5). The set of geological and geophysical surveys included application of methods for identification of faults and fractures using different criteria, with account of the fact that clusters of such structures are indicative of the interblock zones of the crust. We used structural geological methods for studying faults and fractures, morphostructural analysis (including interpretation of satellite images), selfpotential (SP) and resistivity profiling, magnetotelluric (MT) sounding, radon emanation survey, and hydrogeological studies of water occurrences. The region of Lake Baikal is one of the most studied geodynamically active regions of Russia; therefore, published data f...

The subject of comprehensive studies is the underground hydrosphere of the upper crust of the western shoulder of the Baikal rift, being characterized by high tectonic activity in the recent stage of tectogenesis. The studies were focused on the Bayandai-Krestovsky Cape site, considering it as a benchmark for the territory of the Western Pribiakalie (Fig. 1). The available hydrogeological survey database is used to study underground waters circulating at depth of several kilometers. Analyses of deeper waters are conducted on the basis of geophysical data. According to results of initial geological and geophysical studies [Семинский и др., 2010], the crust at the junction of the Siberian crater and the SayanBaikal folded belt is characterized by a hierarchic zoneblock structure (Fig. 2). Regardless of the scale of studies, the territory under study can be divided into sections of two types, that alternate from NW to SE and represent wide highly destructed zones and relatively monolithic blocks of the crust. The Obruchev fault system is distin guished as the main interblock zone (the 2 nd hierarchic level in the study area). It represents the 50 km long NW shoulder of the Baikal rift (the 1 st hierarchic level) and includes the Morskaya, Primorskaya and Prikhrebtovaya interplate zones (the 3 rd hierarchic level). These zones are traced from depth of dozens of kilometers; at the surface, they are represented by fault structures of the highest hierarchic levels.

The structure of the Earth’s crust at the junction of the Siberian craton and Sayan–Baikal Fold Belt was studied along the Bayandai Village–Cape Krestovskii profile (85 km long) by a set of geological and geophysical methods: structural survey, interpretation of long-distance photographs, emanation survey, electrical prospecting with self-potential (SP) and direct-current (DC) resistivity profiling, magnetotelluric sounding, magnetic survey, and hydrogeochemical sampling of water objects. Interpretation of the data refined the main features of the tectonic structure of western Cisbaikalia and revealed the disruption pattern and hierarchic zone–block structure of the Earth’s crust. The Obruchev fault system (≈50 km wide), which is the northwestern shoulder of the Baikal Rift, is the main interblock zone of the studied region. It consists of the Morskoi, Primorskii, and Prikhrebtovyi interblock zones, traced from depths of tens of kilometers and widening near the surface owing to superior structures. The studies gave an insight into the regularities in the occurrence of interblock zones and the criteria for their identification in different geologic-geophysical fields. An efficient complex of methods for mapping the Earth’s crust zone–block structure is proposed.

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The results of studying of unique soils’ genesis and properties in the zone of underground mineral water influence as well as geological conditions are presented on mineral springs sites in the foothills of the Eastern Sayan Mountains. The spatial regularities of soil changes and their dependence on landscape conditions and the composition of mineral water are revealed. It has been established that soils near springs and at a distance of 5 and 20 m are more susceptible to mineral water than distal one at 50 and 200 m. Soil types and its properties change from calcisols that are hydromorphic, thin, gravelly and are formed on travertines, calcites and marbles, to brown soils formed on acidic and ferruginous rocks under the influence of forest vegetation. The salt composition of soils correlates with the mineral water composition and includes ready soluble salts - chlorides, sulfates and bicarbonates of calcium, magnesium and sodium in concentrations from 0.5 to 0.26%, pH changes from acidic to alkaline. The concentration of organic substances varies from 0.5 to 15.0%.