[en] Based on the ore source bed, the strata-bound uranium deposit of carbonate-siliceous-pelitic type in Middle Silurian of West Qinling was formed by hydrothermal infiltrating reworking of ground water, but the uranium enrichment to commercial grade took place after the ore source bed was folded. The main ore-forming episode was the transitional period between mesozoic and Cenozoic. The ore-forming solutions were mainly of the hydrothermal one alimented by meteoric water. The ore-matter mainly originated from the ore source bed itself, which was subject to hydrothermal process by ground water for a long period of time. A great amount of uranyl ions in the solution derived from the ore source bed formed uranyl carbonate complex which was migrated to the trapping protions of lithologies and structure where pitchblende or regenerated uranium black was produced by absorption and co-precipitation, or by reduction, hydrolysis and oversaturated precipitation. The whole metallogenic process of the strata-bound type uranium deposit is characterized by a typically gradual increment, which belongs to a basic model of tower-form accumulation metallogenesis. Epigenetic enrichment played a critical part in uranium ore formation

[en] Uranium deposit No.460 possesses not only considerable size, but also rich ores with a certain reserves. In this deposit the grade of uranium varies widely. Therer are two rich ore accumulation areas with high grade of uranium in the middle-depth and shallow parts of the deposit. The main geological factors for the formation and localization of rich ores in uranium deposit No.460 are the regional geological setting with high uranium content which resulted from two preconcentrations: the intersection of multiple sets of faulted structures with volcanic structures as well as mineralizing channel and the ore preservation conditions provided by the pre-ore hydromicazation; the mutual superposition of mineralization by hydrothermal alteration occurring during the late Yanshanian and Himalayan movements and only sufering from slight denudation and having fine conditons of ore preservation after mineralization

[en] In Tianshan region of Xinjaing, uranium mineralizations are frequently concertrated in some zones, where they essentially belong to same type. Evidently, this results from the control of a same geological metallogenetic process. By way of the geological interpretation of remote sensing image and the investigations in the field, and the digital image processing by computer for some subareas where uranium mineralizations are concentrated, a number of information about ore control regularity have been obtained, that are difficult to be available by general geological methods. Through the analysis of four uranium mineralization ares, the author suggests that favourable areas for search into a sedimentary-modification type of uranium mineralization are present in a variation locations of regional structural line in the transitional areas of platform and geosyncline, with the presence of circular structure constituted by the old stratum. And for search into the epigenetic uranium mineralization, it is necessary to particularly study the characteristics of geological structure on basin-margin and geomorphology. A multi-function combined processing will cause a goos result for the remote sensing image

[en] The basic characteristic, including capacity of column, loading quality of extraction agent, relationship between flow-rate of solution and height of theorical tower plate, leakage of extraction agent, separation behavior of uranium, of TRPO-extraction chromatography for separation of uranium has been inveistigated. The microamount of uranium on column can be eluted with mixed complex solution at pH 5.8-6.2 and determined by 5-Br-PADAP spectrophotometry. The method is simple and easy to operate. It has reasonable precision and accuracy. It is very suitable for determination of 0.002-0.4% uranium in ore

[en] This paper enumerates five examples of applications of radioisotopic ratio in water in granites and volcanic rocks districts. Through measurement results, the variations of isotopic ratio in water at different locations, lithologies and mineralized sections are summarized. The author considers that the regional variations, characteristics of water anomalies and hydrogeological conditions should be fully taken into account in order to select suitable recognition criteria when radioisotopic ratio in water is used as recognition criteria for exploration

[en] By the study of Diwa-type paleokarst and uranium mineralization in uranium deposit No. 387 and southern Hunan province, it has been recognized that the deposit has following characteristics: Specific structural form, i.e paleokarst system; Specific ore-bearing rocks i.e accumulation rocks of paleokarst; Specific form of uranium occurrence i.e discovering in carboniferous pelitic matters of pelitic conglomerate and conglomeratic mudstone, which is mainly in absorption state and with minor pitchblende; The period of uranium formation is long and the mineralization age is basically conformable bo that of accumulation rocks of paleokarst. It is proposed that the formation of uranium deposit No.387 has a principally similar process with the Diwa-type paleokarstification during Yanshanian karstification and diagenesis of the accumulation rocks of paleokarst

[en] The preparation of thin film specimen and XRF method for uranium is described in this paper. The application of uranium M lines in XRF has advantage over correspanding L lines. The former has higher resolution, higher sensitivitys than the latter. Moreover the former has much lower background and higher ratio of peak to background. The detection limit (Cr target, PE crystal, 100 sec. conuting time) is 0.01 ppm

[en] It is attempted to apply the thermoosmotic filtering theory to explan the formation mechanism of the hydrothermal uranium deposits, which occur in sedimentary rocks of exocontact zone near granite massifs. On the basis of 5 forms of physicochemical properties of H₂O occurred in natural rocks, it is considered that it is mainly the bond water which took an active part in the thermoosmotic filtering. H₂O in the thermoosmotic filtering zone of uranium-bearing stratum and the uranium dissolved in the latter tend to migrate toward the contact zone of granitoid with increasing temperature. In contrast to the traditional concept, the ore-forming fluid moved from mineral interstice and microfissuring in rocks to ore-bearing fault zone, then uranium was deposited in an area with sharp physicochemical change and was progressively enriched to form economic valuable uranium deposits

[en] This paper describes the principles of the two field determination methods of the geologic impulse response parameters α(or α-tilde) and the comparison between the accuracies of the values α(or α-tilde) determined by these methods. Theoretical analyses and experimental results have shown that the differential method gives better estimated values of the shape constants α(or α-tilde) with very litlle effect of various measurements errors. The background radioactivity J_γ(φ) does not need to be known for this method. This paper also discusses the influence of the dip angle of the ore strata on the estimated values of the shape constants α(or α-tilde) and the experimental results agree with the theoretically calculated values extremely well. This means that the quantitative subdivision interpretation method by deconvolution technique has such outstanding advantage that there is no effect of bore hole conditions and strata parameters on the interpreted results of γ-logging. Finally, this paper describes the original cause of the presence of 'negative uranium concentration' in interpretation results of γ-logging, and points out that the serious distortion of the uranium concentration distribution in the ore strata will be present if smaller or greater parameters α(or α-tilde) is chosen, especially near the boundary of ore strata. On the basis of this fact, a method that is more effective and universal in determining the shape constants α(or α-tilde) by means of a microcomputer is proposed

[en] This paper briefly presents the calculation method for gravity and magnetic remanence anomality and also discusses its application in studying geological structure and prospecting ore bodies