The question of the genesis of gold mineralization in black shale strata is still one of the controversial issues in geology. The article proposes a geochemical model of gold-quartz mineralization based on the results of the study of geochemical features of the region.
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 genetic relationship between magmatism and endogenous mineralization has always been one of the most important problems of geology and geochemistry. The connection of gold mineralization of the Central Aldan with Mesozoic alkaline magmatism has been discussed many times in the works of Y.A.Bilibin, T.V.Bilibina, E.P.Maksimov, G.K.Shnay, M.P.Orlova and others.
Fundamental studies of Y.A.Bilibin, V.N.Zverev, A.I.Kuks, A.I.Kazarinov, N.V.Petrovskaya and other scientists are devoted to the issues of gold mineralization location in Central Aldan. With some disagreements on the conditions of formation, connection with lithology, tectonics, magmatism, most researchers unconditionally recognize the gyzrothermal-metasomatic nature of gold mineralization of the area and the connection of the latter with the Mesozoic activation of the shield ...
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 connection with the search for blind ore bodies and the evaluation of mineralization at depth, the study of vertical and horizontal zonation has recently received increasing attention. In this regard, the area of the central part of the Miao-Chan Ridge belongs to the region of Mesocenozoic folding and is composed of terrigenous formations of Jurassic age and Cretaceous effusives. Sand-shale strata of the Middle and Upper Jurassic are crushed into northeastern strike-slip folds and unconformably overlain by Cretaceous effusives of acidic and medium composition. The Cretaceous sediments are also folded into gentle folds. Discordant small intrusions of Upper Cretaceous age are widely developed in the area, more often with a characteristic hybrid composition - gabbro, gabbro-monzonites, diorites, diorite-porphyrites. Magmatic activity in the area ended with the introduction of a series of dykes of lamprophyre composition.
The significance of climatic factors in geochemical processes occurring in the near-surface layer, in the oxidation zones of ore deposits, as well as their significance in the formation of peculiarities of the chemical composition of waters, was considered usually for large regions. Thus, A.P. Solovov revealed the conditions of formation of secondary dispersion halos characteristic of arid and humid regions. He cited Central Kazakhstan and the Far East as examples. Eastern Transbaikalia is allocated to a single region, intermediate in climatic characteristic.
Assessment of the prospectivity of newly discovered areas and the choice of further direction of prospecting work in lithochemical surveys are hampered by the bulk determination of metal content in samples, which does not give an idea of the composition of ores, type of mineralization, etc. In this light, the study of the mineral composition of loose eluvio-deluvial deposits from secondary halos of dispersion is of great importance. Interesting results were obtained in the search for polymetallic deposits in Central Kazakhstan ...
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 ...
The formation of secondary eluvial-deluvial scattering halos at lead and molybdenum deposits was usually considered as a process of mechanical dispersion of weathering products of ore bodies and host rocks. As the study of the mineral composition of loose eluvial-deluvial deposits of some deposits of the Eastern Transbaikalia has shown, the formation of secondary scattering halos appears to be more complex.
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 ...
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.
