The study of the degree of mobility of rare and disseminated elements, which are part of such rock-forming minerals-concentrators as biotite and muscovite, is of great importance in the knowledge of endo- and exogenous ore-forming processes.

Features of distribution of chemical elements in rocks are considered as a geochemical criterion in the study of magmatic and sedimentary complexes of rocks and their relationship with minerals. As it is known, geochemical studies increase the depth of search for mineral deposits. These searches are based on the study of the regularity of distribution of chemical elements in rock strata. Consequently, for geochemical prospecting it is important to simultaneously determine many chemical elements and their quantitative ratio in various rocks of separate regions, sites and zones of the investigated territory. In this case, a large number of samples are investigated. It can be hundreds, thousands and tens of thousands of analyses. The main volume of analysis is made up of rocks and loose sediments. Minerals and ores in this case represent a smaller number of determinations, but their performance can be specific ...

Rocks, minerals, and ores are often analyzed by the spectral line attenuation step technique. The advantages of this method over other accelerated spectral analysis techniques are the simultaneous determination of many elements, speed and ease of grade estimation over a large range of detectable concentrations. This makes the method promising for geochemical studies over large areas, prospecting and other geological tasks. In this connection, the reproducibility and accuracy of the method were characterized and its capabilities were evaluated. It was shown that the spectrogram allows to take into account the composition of the sample and determine the content of impurities directly from the calibration graph (not in intervals). On the example of a series of determinations of various elements it is established that the average error with respect to chemical analysis is ±25%.

Identification of regional geochemical regularities by the character of chemical elements distribution in sedimentary rock strata can be achieved by accelerated methods of spectral analysis. However, this requires sufficient accuracy in determining the content of chemical elements in rocks and preservation of the main advantages of spectral analysis: speed, high sensitivity and simplicity. Based on the consideration of the peculiarities of rock samples and simple methods of analysis, it is advisable to use the method of line appearance in combination with a three-stage attenuator (for individual elements) and the method of step attenuation of lines by three orders of magnitude according to M. M. Clair. The M. M. Clair method, unlike other accelerated methods of analysis, simultaneously determines many elements on a single spectrum, in addition, the estimation of content is simple in a large range of determined concentrations. This makes the method promising for mass analysis of rock samples in regional studies.

В геологической практике при поисках рудных месторождений для геохимической характеристики различных комплексов горных пород и рудопроявлений с успехом используются простые производительные методы спектрального анализа. Часто получаемая при этом точность определения содержания в пределах некоторых интервалов (например, 0,001—0,003; 0,003—0,01; 0,01—0,03% и т. д.) при поисках ореолов рассеяния молибдена, олова, свинца, цинка, вольфрама и дру­гих рудных компонентов может быть достаточной. Но в ряде слу­чаев появляется необходимость применения массовых методов анализа с более точным определением содержания исследуемых элементов.

A number of geological questions are solved using spectral analysis data. Spectral analysis also acquires practical importance in geochemical studies, in particular, in metallometric survey. In combination with geophysical methods in parties and expeditions in search and study of scattering halos of various chemical elements, a large number of analyses for lead, molybdenum, tin, copper, zinc, tungsten, antimony, nickel, cobalt, arsenic and other elements are performed. In this case, spectral determinations of metals are made in samples of loose sediments (sediment). When searching for ore bodies that do not extend below the sediment, disseminated mineralization at some distance from the ore bodies can also be detected by spectral sampling of bedrock or sediment from the surface.

Methods of spectral analysis are widely used in the practice of geological exploration. Of great importance for the needs of geology are those methods that are based on simple and accessible techniques of spectral analysis, provide good performance, the possibility of determining a large number of chemical elements on the spectrum of the sample and give a quantitative characterization of the elements determined. Such a method is currently the method of full spectral analysis, when the sample is introduced into an electric arc and for quantitative assessment is used attenuation of the intensity of spectral lines by three orders of magnitude. The content is determined by plotting the number of analytical line steps against the concentration of the element in the samples. However, the process of evaporation and excitation of a particular element depends on the composition of the sample being analyzed. Therefore, the intensity of lines at the same concentration of the element can be different in samples of different composition.

At present, qualitative and quantitative spectral analysis are being introduced into geological exploration in the search for and exploration of various fossils in order to study the material composition of host rocks, mineralization zones, minerals and ores, to study the distribution of rare and trace elements in various types of igneous and sedimentary rocks, as well as to solve other analytical problems. Particular attention should be paid to complete spectral analysis, which can simultaneously determine several dozen chemical elements using a spectrogram obtained by evaporating a 30-40 mg sample of the test sample in an electric arc between carbon electrodes (the test substance is placed in the recess of the lower electrode). The versatility and value of this research method are determined by the speed and the possibility of determining a large number of chemical elements and their content without the use of complex auxiliary equipment. In this case, the method is based on simple and accessible techniques of spectral analysis. In spectral analysis, quantitative determination is associated with an assessment of the intensity of the spectral lines of the elements being studied. The method of weakening lines using a logarithmic sector or filter uses visual determination of the intensity of spectral lines. We have carried out a number of experiments that have allowed us to evaluate the capabilities of the above method and, using nickel and cobalt as an example, to show the higher accuracy of simplified and rapid quantitative determinations of elements in the same samples.

In the directives of the XIX Congress of the Communist Party of the Soviet Union on the fifth five-year plan for the development of the USSR for 1951-1955 in the field of industry, it is indicated, in particular: "Significantly expand the production of non-ferrous metals. Increase production over the five-year period, approximately in the following amounts: refined copper by 90 percent, lead by 2.7 times, aluminum by at least 2.6 times, zinc by 2.5 times, nickel by 53 percent and tin by 80 percent" [1]. This means an increase in geological exploration work, higher requirements for the search and exploration work carried out in terms of efficiency and comprehensive study of the objects under study. For a comprehensive study of ores, rocks and minerals, for a complete characterization of the constituent elements, spectral analysis at all stages of geological exploration work is especially important.

Thanks to the creation of high-quality domestic equipment for studying minerals and ores, spectral analysis methods are becoming increasingly important both in studying the material composition of deposits, host rocks, mineralization zones, etc., and in quantitatively assessing the content of ore components in them. Spectral analysis is of particular value in field conditions, increasing the efficiency of geological exploration and allowing a preliminary assessment of the objects under study. Experimental studies conducted by us on the material of studying copper pyrite ores allowed us to develop a method for rapid quantitative spectral determination of copper in field conditions without the use of complex additional equipment. Methods of quantitative spectral analysis are based on an unambiguous relationship between the intensity of the spectral lines of elements and the concentration of these elements in the substance under study. This relationship is established by comparing the spectra of samples and standards visually or with a microphotometer by measuring the blackening of the spectral lines.