Vol 64 Iss. 2

Now it has become generally accepted the idea of the leading role of the scattered type of existence of chemical elements in the Earth's crust, on the background of which are observed increased concentrations of elements, under certain conditions referred to as ore occurrences or mineral deposits. The formation of increased concentrations, of course, is possible only under the condition of energy expenditure, the source of which can be processes of both endogenous and exogenous character.

Small intrusions and extrusive formations, represented by montschikites, picritic porphyrites, camptonites, analcime basaltoids, monzonites and their transitional varieties, are widely developed within South Gissar. They occur among the Upper Paleozoic granitoids of the Gissar batholith and volcanogenic strata of Lower Permian age.

Long-term prospecting and exploration works in the Kola-Karelian region have established the confinement of mica-bearing pegmatites to alumina gneisses, theoretically substantiated by G. I. Buntin, D. I. Buntin, and D. I. Buntin. I. Buntin, D. S. Korzhinsky, V. D. Nikitin.

Numerous aspects of the extremely complex problem of zonality of postmagmatic ore deposits have been considered for several decades by many Soviet and foreign researchers - V. Emmons, S. S. Smirnov, Y. A. Bilibin, N. A. Khrushchev, P. M. Tatarinbv, V. I. Smirnov, V. V. Shcherbina, Y. Kutina, etc.

The Nezhdaninskoye gold deposit is located in the northern part of the South Verkhoyansk synclinorium and is situated in the vaulted part of the southern periclinal closure of the box-shaped Dybinskaya anticline. The intervening rocks are represented by a monotonous thickness of sandy siltstones and shales of Lower Permian age.

All the most interesting in practical terms deposits and ore occurrences within the South Slope of the Gissar Range are hydrothermal in nature and localized within the zones of rupture faults. In this connection, geochemical sampling of the material composing the zones of tectonic faults becomes extremely important, because it is obvious that the basic patterns of element introduction or removal in the faults can be used as geochemical criteria for age dissection of faults or assessment of prospects for their metalliferousness.

When searching for deep-seated ore bodies by primary halos usually use two main parameters: zonality and the gradient of element content in primary halos along the upthrust, across and along the strike of ore zones. To study zonality, it is important to assess the stage of ore deposition. Only by assessing the stage of ore deposition, it is possible to study zonality and use it both to search for blind ore bodies, and to assess the level of erosion cut and the prospects of deep horizons of ore bodies that have not been uncovered by erosion.

In addition to copper-nickel mineralization, pyrite-pyrrhotite mineralization is widespread in the Monchegorsk region, and prospecting geologists often have to solve the question of the relationship between pyrite-pyrrhotite mineralization and copper-nickel mineralization. Until recently, most of the identified pyrite-pyrrhotite ore bodies were traced by mining and drilling operations in the hope of a possible transition of pyrite-pyrrhotite mineralization into copper-nickel mineralization, but not a single case of such a transition has been established.

The experimentally substantiated hypothesis of the existence of film halos was first put forward by N. F. Mayorov. A system of differential equations was proposed to quantitatively describe the concentration distribution in film halos...

Lithochemical survey in the conditions of the Kola Peninsula and Karelia is now beginning to be widely used in combination with geophysical methods at the stage of detailed prospecting. Drilling verification confirms the high efficiency of the method, which allows rejecting numerous geophysical anomalies caused by virtually nickel-free pyrrhotite ores and objects of non-metallic nature.

When searching for sulfide ores, sulfur is usually not determined in lithochemical samples. Meanwhile, at clark values in the lithosphere of 0.047%, its content in sulfide ores reaches tens of percent. Thus, in samples of sulfide copper-nickel ores of Allarechensky and Monchegorsk districts of the Kola Peninsula up to 27-33% of sulfur was found, in .samples of pyrrhotite ores of Allarechensky district 20-26%.

Based on the theoretical analysis of the distribution of element concentrations in the residual scattering halos of vein-shaped ore bodies, R. I. Dubov proposed to interpret the halos using specially calculated and constructed in semi-logarithmic scale palettes of theoretical curves. Interpretation with the help of palettes, as it is known, consists in combining the practically obtained curve, constructed in the same scale, with one of the theoretically calculated curves. The disadvantage of the palette method of interpretation is the necessity of interpolation between neighboring curves on the palette. The similar nature of curves with different parameters can lead to ambiguity in the solution.

Partial exit of radon into the well, subjected to prolonged flushing during drilling, leads to a decrease in the intensity of radiation along the axis of the well and underestimation of linear uranium reserves according to gamma logging data.

Uranium content in rocks by gamma-spectrometric and radiochemical methods is determined on the assumption of radioactive equilibrium between uranium and radium. Studies of the state of radioactive equilibrium in rocks are contradictory. Some researchers indicate significant disturbances of radioactive equilibrium, while others indicate the existence of equilibrium within the accuracy of the methods used to determine uranium and radium.

Radon and thoron are one of the constituents of the Earth's atmosphere. The distribution of radon concentrations has been studied quite completely. Much less information is available on thoron concentrations in the atmosphere. Significant diurnal and seasonal variations of radon concentrations in the surface layer of the atmosphere have been detected. The concentration of radon and thoron in atmospheric air is determined by their exhalation from rocks and soil, as well as by turbulent mixing in the atmosphere.

In recent years, interest in studying the chemical composition of metamorphic and ultrametamorphic rocks of ancient shields as possible analogs of the substance of deep zones of the Earth's crust has increased. Special attention of researchers is attracted by the distribution of radioactive elements in these rocks in connection with the problems of the thermal regime of the Earth's crust, the evolution of the material composition of rocks in the course of their geological development, the determination of the primary nature of metamorphic strata.

The most promising method of sampling of uranium-thorium ores, which allows separate determination of uranium and thorium, is the gamma-spectral method in modification of measurements of the difference effect of radiation. The principle of such sampling is considered earlier...

The development of gamma-spectral methods for in situ sampling of complex uranium-thorium ores and the associated increase in the amount of information obtained requires the development of accelerated methods of interpretation of measurement results. The proposed counting and solving device allows to increase approximately twice the productivity of gamma-spectral measurements processing in comparison with the usual nomographic method, is characterized by universality, high reliability and long service life.

Continuous recording of equivalent contents of radioactive elements instead of registration of count rates in differential channels during gamma-spectral measurements allows to quickly obtain information on the distribution of elements in the studied object and simplify the processing and interpretation of results. This method is used for search gamma-spectral surveys in motion. We have used continuous recording of uranium (by radium) and thorium contents in gamma-spectral logging at the site of two-component uranium-thorium ores.

The largest deposits of Iceland spar are confined to lava beds of basic composition (the first type of deposits), to small dolerite intrusions (the second type of deposits), and to zones of tectonic crushing in tuffogenic rocks (the third type of deposits). By now, the known deposits have been relatively well studied and the main geologic regularities of their spatial distribution have been revealed.

The electronic energy scale stabilization circuit is a device that monitors the photopeak of a gamma ray repeater. The basis of the scheme are two adjacent differential channels with the same window width, tuned, respectively, to the left and right branches of the photopeak of the reference source. At the output of both differential channels is placed a comparison circuit and an actuator...

The concept of effective atomic number Z_ef of rocks and ores follows from the idea of equivalence of γ-quantum properties of media of different material composition and is of fundamental importance for the development of γ-γ-methods of nuclear geophysics.

The effective application of gamma-gamma density logging in the dissection of a geologic section is largely determined by the correct choice of the distance between the source and detector of radioactive radiation (probe length), the integration constant and the speed of the logging tool.

The distribution of gamma quanta along the directions of motion is one of the main characteristics of gamma fields. Data on the angular distribution of gamma rays are used in the design of probe devices, selection of optimal geometric conditions and methodological techniques of measurements in nuclear geophysical methods of studying rocks.

The different spectral composition of gamma radiation of uranium and thorium ores determines the specificity of taking into account the attenuation of radiation in casing pipes and washing fluid when interpreting gamma-spectral logging diagrams.

1.In estimating confidence limits for the mean metal concentration in ore, data on the moments of distribution and the number of samples are taken into account. It is also important to have an idea of the degree of independence of differences between determinations, since the usual statement that the variance of the mean is n times less than the variance of a single determination is valid only for determinations with independent variations (n is the number of single determinations).

The influence of host rocks on the regularities of quartz veins location within the crystal fields, vein genesis and formation of. crystal nests are quite widely covered in the domestic literature. In many crystal-bearing fields, the confinement of quartz veins to certain compositional strata, which are considered to be productive with respect to crystal formation, has been noted. All researchers to a greater or lesser extent note the influence of rocks on the mineral paragenesis of crystal nests, and some consider the host rocks as a source of silica in the formation of not only crystal nests, but also quartz veins themselves.

One of the most promising criteria of nickel bearing capacity of basic-ultrabasic massifs is naturally considered to be the content of nickel, the main component of copper-nickel ores, in non-ore rocks. The main difficulty in applying this criterion is the unevenness of the background nickel content, which in the series of basic-ultrabasic rocks increases from the most acidic representatives of the series to the most basic ones. This phenomenon was first taken into account by D. V. Polferov.

The task of discriminant analysis is to assign an object characterized by a set of I features to one of (in our case, two) l-dimensional populations (A or B). We will call the samples from these populations class A or B, respectively.