The Uryakh ore field (NE Transbaikalia): Formation of structural assemblages in the centroid-type seismic regime

Syn-ore centroid type deformations that produced unusual structural assemblages are identified in the Uryakh ore field. The regularities of the deformation process comparable to a mechanism of the centroid-type seismic focus are established. The results of studying fluid inclusions suggest that the pressure—temperature parameters of the system correspond to conditions typical of the seismic regime. A model of formation of structural assemblages in a centroid-type dynamic regime with the participation of fluids is proposed for the first time.     

The earthquake foci and deep structure of the Earth’s crust and upper mantle along the southern Sakhalin-Sea of Okhotsk-Kamchatka profile

The Kuril-Kamchatka seismofocal zone was thought to be a single plate approximately 90 km wide and dipping to a depth of 700 km at an angle of 40°–45°. This concept reflects primarily the physical differences (elastic wave velocities, density, temperature, etc.) between the seismofocal zone and the mantle hosting it. Detailed investigations show that the seismofocal zone proper is also heterogeneous with earthquake hypocenters variably concentrated and clustered within this zone, where both seismogenic and aseismic strata, as well as subvertical zones, can be identified. The latter are reflected in the structure and faults of the Earth’s crust and upper mantle.     

Structure of ore fields and deposits: Current status and outlook for further development

The current status of investigations of the structure of ore fields and deposits in Russia is considered. The importance of traditional lines of research in this field and the great body of information acquired is emphasized. The changes in ideas of geodynamic and tectonic crustal evolution have made it necessary to alter concepts of the geological and structural position of ore fields and deposits. New challenges are caused by these changes and progress in the knowledge of ore deposits and the depth of their formation, as well as geodynamic, tectonophysical, and hydrodynamic processes in ore-bearing crustal blocks. The results of hydrodynamic modeling of deposit formation controlled by deeply penetrating fault zones are discussed. Various relationships between hydrodynamic and structural factors in ore formation are considered.     

Boundary waves at the water-sea bottom interface

Doklady Earth Sciences -     

Groundwater quality formaiton at water intakes of lacustrine type

The results of many-year hydrochemical observations in several water intakes on the Valdai Hills are generalized. The formation of groundwater quality in karst carbonate deposits is studied. The extent of interaction between operated aquifers and the accumulation of some toxicants in bottom sediments of lake systems is analyzed.     

Assessing the Hazard of Environmental Pollution by Landfills of Industrial and Municipal Wastes

Water Resources - The environmental effect of landfills of solid municipal wastes is considered, including their effect on groundwater. The accumulation of municipal wastes causes considerable...     

Precipitation pollution effect on groundwater hydrochemical regime

Pollution of precipitation is one of the main factors affecting the hydrochemical regime of groundwater. The main factors governing the concentration of macro-and microelements, as well as the degree of acifidication, have been evaluated on the basis of the long-term variability of the hydrochemical regime of groundwater. The results follow from the generalization of the data obtained. Changes in the macro- and microelement concentration in groundwater have been studied, taking into account the chemical composition of rainwater and snow meltwater.     

Structural–Hydrodynamic Organization and Functioning of the Ore-Forming System of the Irokinda Au Deposit (Northeast Transbaikalia)

Doklady Earth Sciences - New data on the structural–hydrodynamic organization of the ore-forming system (OFS) of the Irokinda deposit in the architecture of deep-seated faults are presented....     

Thermal conductivity of sediments in high-latitude West Siberia

The thermal conductivity of rocks (λ) used previously to estimate heat flow in high-latitude Siberia was assumed to be λ = 1.8–2.0 W/(m?K), according to published evidence, but was almost never measured specially. We measured the thermal conductivity of core samples from boreholes drilled in the northeastern West Siberian Plate and in the Yenisei–Khatanga basin in the 1990s, using two advanced instruments: a comparator and a scanner of thermal conductivity. Altogether there were 305 samples of air-dry sediments (λ_d) from the 1100–4200 m interval of 23 holes, out of which 77 samples were then moistened (λ_w). The average thermal conductivities of rocks in dry and wet conditions were found to be λ_d = 1.9 ± 0.2 and λ_w = 2.6 ± 0.1 W/(m?K), respectively. Thus, the true thermal conductivity of sediments, which are saturated with water in this northern area, must be about 20–30% higher than that assumed in the previous heat flow determinations, and the latter are thus underestimated correspondingly. The updates to the thermal conductivity values imply major revision to the existing ideas of the thermal regime in the Siberian high latitudes. Such a serious revision of geothermal data will obviously require a large amount of additional experimental work.