[en] Technique for radioisotopic decoration of polished sections using ¹⁹⁵Au autoradiography is described. Trace autoradiography (a - microradiography) was performed using A-2 type thick-layer plates while contrast radiography of summmary α- and β-radiation was performed using PM-1 type X-ray film. The exposition is 10-60 days. The technique described permits to identify subtle peculiarities in the mineral distribution, gold in particular, as well as to simulate in a certain degree the interaction processes of concrete mineral associations with solutions containing the element investigated in concentrations close to the natural ones

[en] The problem of transverse zoning of island arches is considered. Reasons for U and Th content difference in separate volcanoes and volcanic zones, constituting one and the same province are analyzed. The published results of measuring U and Th content in volcanites of Kurilo-Kamchatskaya province, the Japanese Isles, the southern part of Kamchatka are used for comparison with the data on Zakarpatskaya depression. Mean values of radiogenous heat generation have been calculated for every volcanic zone. Two groups of volcanic structures have been singled out according to their radiogeneous properties. The radio-activity of magmatic formations in structures of both types increases in direct proportion to the basement structure complexity, which ref--lects the cyclic recurrence, duration and intensity of its development. Stated is the combining of U, Th and K summarized mean concentrations in rock structures of the first type and their abundance in basement rocks, with a corresponding silicic acidity

[en] Reasons determining deviations of absolute age values at radiologic dating are considered. Thermal rock annealing in postmetamorphic period is considered to be the main reason. The examples are given enabling detection of warm-up traces by certain signs. The method and its shortcomings are discussed. The dependence of metamorphite dating results on age obtaining method (K-Ar, Rb-Sr, Rb and so on), defficiency and chimism of the studied crystal, monocrystal size, speed, duration and character of complex cooling, annealing temperature, heat effection duration, warm-up cycle quantity and so on is proved. None of the above factors is of any consequences. This testifies to the fact that the use of some chronological and empiric data appears in the whole to be impossible at separation of metamorphism stages and their age determination

[en] Petrochemical alterations of sedimentary rocks are studied, which occurred near the contact metamorphism of the contact zone of granitoides of the Calbine complex. Two trends are established in the alteration of sedimentary rocks manifesting themselves at different areas of contact. The first one is K₂O, Th and U addition rocks, being in direct contact and at the distance of 10 m from the contact, and the second one is addition of Na₂O and CaO to the zone near contact rocks 300 m wide and removal of K₂O, Th and U out of it. Besides, in both cases rock general ferrousness and the degree of Fe oxidation state in them are reducing. K addition out of magmatic hotbeds of granites occurred, most probably, by diffusion way, and Na addition by infiltration way. Probably, the use of these two ways of transfer manifesting themselves separately, caused the two trends in the alteration of containing rocks

[en] The results of studying the two-dimensional and multidimensional correlational links between the tempered induced losses and the contents of other principle components of bauxites and the rock from Amangel'di group bauxite horisons are presented and analyzed. These relations are shown to be strong enough to be used in an express nuclear-physical analysis, which involves either respect for the samples humidity effect on the ultimate results or its cancel

[en] Studied has been post sedimentary uranium distribution in cenozoic sedimentary deposits of the Western Siberia by means of determination of uraniUm amounts in allochthonous leucoxene which initially did not contain uranium. The study of uranium distribUtion in selected minerals has been carried out with an aid of microradiographic analysis of sections. Investigation results and previously established experimental ability of titanium hydroxides to separation from solutions of uranium hydroxides permit to make a supposition that in nature Ti hydroxides are capable of uranium concentrating. Ti hydroxides are formed in the process of change of Ti-containing minerals. At infiltration of uranium-containing minerals with oxygen waters in grey-colour sediments uranium can be extracted by leucoxenes. The utmost U amounts are established in the intermediate zone on the boundary of oxidation-reduction conditions

[en] Considered are peculiarities of U, Th, K distribution in enclosing and altered wall rocks and ores of three formations: essentially fluorite, quartz-calcite-fluorite and quartz-fluorite with bertrandite. It is concluded that the investigated objects of fluorite-phenacite-bertrandite formation are characterized by specific features in natural radioactive element (NRE) distribution, expressed in high Th concentrations in ores and young granitoids, paragentically connected with fluorine-beryllium mineralization. Thorium mineralization is developed more completely at those objects, where preore alkaline metasomatosis with Na alkali predomination in the composition is displayed stronger. In the late hydrothermal stage of mineralization formation Th potential has dropped in solutions and U takes an essential role. Shown is the possibility of using distribution peculiarities of NRE for prospecting of fluorine-beryllium deposits

[en] The behaviour of radioactive elements (RE) during formation of multiphase intrusive series of various ages, types and alkalinity nature, placed in different structural formation zones of West Uzbekistan is discussed (on the basis of 230 quantitative determinations). It is established that maximum RE concentrations in the intrusive series considered are U=3-5, Th=11-17 g/t and correspond to granodiorites, adamellites, granites and granosienites. The typical behaviour for U and Th is the growth of their concentrations in the direction from gabbro- to granodiorites (granosienites) and granites, and then decrease to leucocrat granites (alkaline, biotite or bimica ones). The evolution of magmatic systems occurred not along the line of differentiation of melts, but along the line of their ''washing'' with fluid mainly at the level of magma generation and on their way to upper horizons of Earth crust. High concentrations (several times more than a clark) must occur in cases of additional RE introduction

[en] New data of the U-Pb dating of zircons of magmatic and metamorphic complexes of the Baikal-Patomskoe Upland are presented. More than 40 uranium-lead data were analyzed. The results obtained permit to conclude that the region has a polycyclic development. Main geochronological stages of the magmatic and metamorphic events were established. Lower Proterovic substrate age is found to be 2114+-22 millions of years. Late Kerelian (Akithan) stage (1800-1860 millions of years) are revealed as well as Early Paleo oic (556-420 millions of years) and Hercynian (340-270 millions of years). Violations in the zircon radiological systems are in the range of 473+-23 million of years. Geochronological gap (^window⁾ was found to bt in the limits of 1800-1300 millions of years

[en] U and Th distribution in rocks of the massif of alkaline-granitoid formation is studied using the methods of γ-spectrometry and neutron- fragment radiography. Predominant accumulation of U and Th in final products of magmatic differentiation - foyaites - is established. U and Th concentrations increased sharply during postmagmatic stage of alkaline massif formation - in permatites and metasomatically alterated rocks (Th/U and U/K ratios can serve as criteria for identification of such formations). The increase of U part, connected with accessory minerals in pegmatites and metasomatically alterated rocks, is pointed out. For U in postmagmatically alterated rocks high concentrations due to microcracks are characteristic