Volume 74, Nº 5 (2019)

The tectonic evolution of the Earth is the leading factor that accounts for the uneven distribution of lead and zinc reserves through geologic time. The cyclic changes in lead–zinc ore formation productivity reflected the periodic amalgamation of most continental crustal blocks and supercontinent formation, stabilization, and eventual breakup. Many features of the age spectra of lead and zinc reserves are caused by the gradual growth of the continental crust as a result of the accretion of island arcs to the cratonic nuclei, the widening extent of the ensialic environments of ore formation, and the increasing role of the continental crust in magma generation processes.

The differentiated Bushveld Complex (the Republic of South Africa) has been studied on the basis of remote space and gravity-magnetic surveying. This article demonstrates the possibility of using Landsat 7 ETM+ multispectral space surveys and brightness parameters to predict platinum mineralization in new promising areas. Analysis of the gravitational field has shown that platinum mineralization in the studied area is concentrated in a rather narrow range of values, which enables one to use these data as a prospecting indicator. The main conclusions were made and the ability of Landsat 7 ETM+ multispectral space surveys to forecast platinum mineralization in new promising areas was demonstrated. These studies demonstrated the efficiency of integrated remote (space and geophysical) methods for the improvement of the approach to prospecting for platinum–copper–nickel mineralization.

This paper presents the first results of hygrometric analysis (sorption isotherm method) of the contents of bound water types for nonextracted rock samples of the Bazhenov Formation. The water sorption isotherms are characterized by an evident S shape, which allows determination of the maximum amount of mono-, poly-, and capillary condensation bound water and provides important conclusions on the hydrophilic properties of rocks of the formation. According to the morphology of the sorption isotherms, the amount of bound water, and their similar mineral compositions, nine samples were combined into four groups; other samples were considered individually. A correlation between the content of pore water and the amount of mono- and polylayered water was found.

The water phase transition divides two approximation areas of ground from the standpoint of its elastic properties. It is of interest to study the changes of the acoustic characteristics, both kinematic and dynamic, in the process of freezing and thawing, because they can be indicators of various inelastic characteristics of the transition from one state to another. This paper reports the solutions of the following problems: the design of a measuring cell that introduces minimal distortions in ultrasonic P- and S-wave measurements, monitoring of sample temperature, ultrasonic measurements with a time step that provides the necessary characterization, and analysis of recorded wave patterns and their variations in the course of the phase transition.

The existing ideas about the structure of engineering geology are considered, its modern assessment is given taking account of an emerging discipline, that is, space engineering geology. It is shown that the theoretical basis of engineering geology collected to date allows us to proceed to the creation of a general theory of this science as a system (logical combination) of its own basis of concepts, patterns, and laws, basic and auxiliary theories representing a unified teaching of engineering geology, which possesses descriptive, explanatory, heuristic and predictive functions. Logical and graphical models of the content of the general theory of engineering geology and its disciplines are proposed, which can serve as the basis for their subsequent development.

The sulfur isotope composition was measured in the main morphological types and generations of sulfides composing the ores of the Dzhusa deposit and the contents of trace elements were measured using highly sensitive laser ablation-inductively coupled plasma-mass spectrometry (LA–ICP–MS) for the first time. According to the sulfur isotope geochemistry, we assume that a deep magmatic source made a predominant contribution to the ore-forming fluid. Using the STATISTICA software modules, correlation analysis was performed and the trace element distribution patterns in sulfides were revealed.

The results of geological interpretation of data of engineering seismic surveys obtained during the field works at Lake Onega are given. Seismic-stratigraphic units specified on processed seismograms are characterized. The survey enabled us to compile a seismic-stratigraphic column of the Quaternary sediments of Lake Onega, which may be used to analyze the structure of the open part of the lake.