Mudflow processes play a very significant role in the formation of channel sediments in mountainous areas.

Geochemical criteria are established on the example of one of the fields in Yakutia. Climatic conditions predetermined the widespread development in the area of permafrost up to a depth of 300 m.

The year 1927 was coming to an end. The country of the Soviets was overcoming the devastation of the world and civil wars. On the agenda was set the issue of development of the national economy, primarily heavy industry. For this purpose new fields were needed, they had to be found quickly and economically ...

In geochemical studies, two basic parameters, mean grade and variance, are used to characterize rocks and ores. It is easy to show that regardless of the nature of the spatial distribution of element content in the studied object at a sufficiently dense and uniform sampling network, the average content of the element is equal to the arithmetic mean ...

The deposit is confined to the southern periclinal closure of the anticline, composed of a monotonous thickness of calcareous-clay siltstones and shales. The rocks are characterized by abundance of pyrite and marcasite nodules. The rocks are not characterized faunistically, but lithologically they parallel the Kukkan Formation of the Lower Permian of the unified stratigraphic scheme of the Southern Verkhoyany. The mineralization is localized in crushing and buckling zones of near meridional strike and in quartz veins of near-latitudinal strike. Both have a steep dip at an angle of 70-80°; the zones are westward, and the veins are northward ...

In the predictive evaluation of ore-bearing areas, the researcher faces two tasks - what to look for and where to look? A sufficiently clear answer to this can be obtained if the entire set of geological, geophysical and geochemical data is used, and the nature of these data and their relative role depend on the stage of prognostic assessment.

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.

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.

In prospecting lithochemical survey on residual eluvio-deluvial scattering halos, samples are taken, as a rule, from a depth of 15-20 cm, immediately below the vegetation layer. At the same time, it is known that metal concentration in the halo decreases with increasing thickness of deluvium. Obviously, when the thickness of the deluvium is significant, the metal concentration in the subsurface layer may become below the sensitivity limit for the determination of this element. With very sensitive methods of sample analysis, the depth of the lithochemical survey will be limited by the accuracy of the analysis and the irregularity of the useful metal content in the bedrock containing the ore body. On this basis, in lithochemical survey it is necessary to have at least a rough idea of the depth of the method - the limiting thickness of eluvium-deluvium, at which in the subsurface layer metal concentrations will still be sufficient for reliable detection of the halo.

As a rule, works considering the geochemical specialization of rocks concern intrusive formations and mainly granitoids, since they dominate the lithosphere and are naturally the most thoroughly and comprehensively studied. It seems interesting to analyze the geochemical specialization of the main effusives (basalts) of some areas of the Pacific ore belt, mainly from the point of view of its relation to the tin content of the region.

Head of the Department of Geochemical and Radioactive Exploration Methods, Professor, Doctor of Geological and Mineralogical Sciences Nikolai Konstantinovich Morozenko was a communist, a major scientist, one of the best experts in the geology of rock crystal deposits and natural riches of Central Asia, Pamir and Altai.

According to the law of universal dispersion of chemical elements (Clark-Vernadsky law) in each drop or dust particle of matter on our planet can be found all the elements of the Mendeleev table. Their quantitative ratio in different shells of the globe and more local geological objects is determined by the nature of each element - its individual geochemical features. The closeness of geochemical (chemical and physical) properties is due to the similar behavior of elements in geological processes and joint accumulation in certain geological formations or shells of the globe. The latter circumstance makes it possible to subdivide chemical elements into a number of categories according to geochemical features and, first of all, according to their relative abundance in various geological objects or shells of the globe.

Geochemistry, as a science that studies the chemistry of the Earth in its historical development, originated at the end of the XIX century and finally formed as an independent branch at the beginning of the next century, mainly due to the works of our compatriots - V. I. Vernadsky and A. E. Fersman, as well as W. M. Goldschmidt, F. W. Clarke and X. С. Washington. The further development of geochemistry is due to the studies of A. P. Vinogradov, A. A. Saukov, V. V. Shcherbina, and others. Practical use of the general provisions formulated in the works of the founders of this science, also began in our country in the years of the first Five-Year Plan.

The compilation of geochemical maps should be preceded by a clear formulation of the concept of geochemical map. As it is known, there are different points of view and different understandings of map construction and practically there is no experience in making polyelemental geochemical maps.Under geochemical the authors understand a map that reflects the content, character of distribution and form of finding a wide range of chemical elements in the bedrock. Such a map should be one of the main in the creation of metallogenic and prognostic-geological maps ...

As is known, the main, if not the only, method of prospecting for gold deposits until the last decade was a schlich survey. Since 1956, in Eastern Transbaikalia and then in other areas along with the schlich survey are increasingly used geochemical methods, which became possible due to the use of highly sensitive adsorption-spectral method of analyzing samples for gold. Then electrochemical-spectral, double-arc spectral methods were proposed, among which the electrochemical-spectral method is the most widely used. All these analytical methods were developed for the analysis of lithochemical and, to a lesser extent, biochemical samples. For hydrochemical samples there are still no reliable express highly sensitive methods of gold determination. The works of VITR, Leningrad Mining Institute and other organizations have not yet left the experimental stage, although there are already some recommendations. This article is based on the materials obtained during research within the Lubavinsky ore field, as well as the materials of N. I. Safronov, V. V. Polikarpochkin and others in Eastern Transbaikalia, A. M. Grigoriev in Buryatia, L. V. Razin and I. S. Rozhkov in Yakutia ...

When developing the problem of formation of eluvio-deluvial scattering halos, clarification of the role of salt and mechanical dispersion of various metals, quantitative assessment of ore occurrences by scattering halos, it is necessary to know the distribution of metal by size classes in lithochemical samples ...

To assess the accuracy of spectral analysis, it is necessary to have at one's disposal, as usual, several dozens of twice analyzed samples. Since in semi-quantitative spectral analysis discrepancies between repeated determinations are quite large, and the analysis is usually received, as a rule, samples with sharply different grades, the assessment of the accuracy of the analysis should be carried out in relative units ...

The Lyubavinskoye gold deposit, located in the upper reaches of the Onon River, has been developed since the end of the last century. V. A. Obruchev, who visited the deposit in 1912, published the first summary work on the geology and minerals of the area, which has not lost its significance to this day. Later, V.M. Sergievsky (1936) and M.I. Tulokhonov (1958) carried out geological survey works in the area. In the summer of 1960 within the limits of the Lyubavinskoye ore field were carried out complex geological-geophysical and geochemical studies by teachers and students of the Leningrad Mining Institute.

In the metallogeny of magmatic rocks of the Khapcheranginsky ore district some researchers assign the leading role to granite porphyries and granodiorite porphyries, felsites and quartz porphyries of the Verkhneononskaya group of small intrusions, granite porphyries of the Khapcheranginsky stock and granodiorites of the Khamaro-Tyrinsky intrusive massif.

Considering the possibility of estimating the scale of expected native mineralization on the basis of calculating the total (integral) metal content in the halo, A. P. Solovovov for ore bodies of linearly elongated shape proposed a formula ...

In the search for gold deposits since time immemorial successfully used schlich survey, based on the study of mechanical halos and scattering fluxes of nugget gold. The use of geochemical methods based on the direct indication of finely dispersed gold in samples of small weight has become possible only in recent years due to the introduction into practice of the adsorption-spectral method of analyzing lithochemical samples, proposed by N. I. Safronov. However, this method, which achieves a sensitivity of 1-3·10^(-6) %, involves complex preliminary chemical treatment of samples. Even more complicated is the chemical preparation of samples for analysis in the assay-spectral method (sensitivity 10^(-8) %). The chemical preparation of samples is somewhat simpler in the electrochemical-spectral method, which has approximately the same sensitivity as the adsorption-spectral.

Одним из наиболее эффективных методов при поисках рудных ме­сторождений является металлометрическая съемка, основанная на изу­чении вторичных ореолов рассеяния, развитых в рыхлых элювиально­делювиальных отложениях. Металлометрической съемкой ежегодно ис­следуются значительные площади во всех рудных районах страны, в том числе и в Восточном Забайкалье, где почти все известные месторожде­ния и рудолроявления сопровождаются вторичными ореолами рассея­ния различной формы. Чаще форма ореолов повторяет очертания руд­ных тел, но встречаются и ореолы, сильно вытянутые вниз по склону. В таком случае простирание рудных тел обычно оказывается не совпадающим с простиранием ореолов рассеяния. В ряде случаев над извест­ными, довольно богатыми рудными телами не обнаруживаются вторич­ные ореолы рассеяния. Например, на одном из вольфрамовых месторож­дений Восточного Забайкалья богатые кварцево-вольфрамитовые жилы, приуроченные к эндоконтактовой зоне небольшого гранитного массива, остались -незамеченными при проведении детальной (металлометрической съемки. Наряду с. этим значительно менее богатые кварцево-вольфра­митовые жилы, развитые в экзоконтактовой зоне массива, сопровожда­лись достаточно четкими ореолами рассеяния вольфрама. Причины такого явления удалось установить при анализе геоморфологической об­становки исследованных участков месторождения. Оказалось, что харак­тер вторичных ореолов рассеяния, приуроченных к элювиально-делюви­альным отложениям, зависит от условий формирования этих отложений. Формирование же рыхлых элювиально-делювиальных отложений самым тесным образом связано с процессом формирования рельефа того или иного участка.

Металлометрическая съемка на базе спектрального анализа как поисковый метод впервые в Союзе была применена в 1935 г. на Хапчер аннинском месторождении олова. В настоящее время металлометрия стала ведущим поисковым методом в ряде районов, перспективных на «олово, цветные и редкие металлы. Тем не менее, проведение ее сталки­вается с трудностями именно при поисках оловянных месторождений.

Вольфрам относится к числу элементов, при поисках которых ме­таллометрическая съемка сталкивается с некоторыми затруднениями. Так, в Восточном Забайкалье на ряде рудопроявлений, представленных залегающими среди гранитоидов кварц-вольфрамитовыми жилами, при обычной методике съемки не было зафиксировано четких ореолов- рассеяния вольфрама. Иногда он фиксируется в разрозненных пробах, что не позволяет с удовлетворительной точностью задавать горные вы­работки для вскрытия рудных тел. Для разработки наиболее рацио­нальной методики отбора и обработки металлометрических проб необ­ходимо знание распределения искомых элементов в рыхлых отложе­ниях.

He solution of various geological exploration problems by geophysical exploration methods is generally divided into two main operations: 1) the study of the physical field (magnetic, gravitational, etc.), against the background of normal values ​​of which anomalous values, caused by the influence of various geological objects, are more or less clearly distinguished; 2) geological interpretation of the physical field, i.e. decoding (quantitative or qualitative) of anomalous values As a result of these measurements, sometimes quite complex, including in the overwhelming majority of cases elements of mathematical processing, and in some cases interpretation (seismograms, spectrograms), exploration geophysicists will receive for each point where the measurement was made, a certain value of the parameter of the physical field. Based on these values, graphs, contour maps, vector plans, hodographs, etc. can be constructed, which are the main and only material subject to interpretation in the geological sense of the word. However, before proceeding to the interpretation of the obtained graphs, maps, hodographs, etc., it is necessary to have a very clear idea of ​​their reliability, or, in other words, it is necessary to take into account the magnitude of the error made during measurements, which characterizes the field accuracy of observations. Although the field accuracy of observations is not the only factor determining the accuracy of the geological interpretation of results, in a number of cases it plays a very significant role along with other factors (observation network, physical properties of rocks, etc.).