Showing papers in "Uranium Geology in 2012"

The Main Advance and Achievements in the Potential Evaluation of Uranium Resource in China

Abstract: The national uranium resources potential evaluation is one of the important national census in China.The evaluation is based on the data and results accomplished by nuclear geological industry in last decades and wholly performed on GIS platform by absorbing related technology and geological achievement in home and broad,and has figured out 329 uranium predicted mineralization areas and estimated more than 2 000 000 tones resource on a national scale.Innovative achievements has been made in the classification of uranium deposit type and mineralization belt,integration of geological-geophysical-geochemical-remote sensing information and research of uranium mineralizing pattern.For the first time,the potential evaluation has been performed totally by digitalization and information,the evaluation will provide important evidence for developing middle-long term planning of uranium exploration and laid good foundation to future dynamic and reqular evaluation of uranium resource in China.

Discussion on the Physicochemical Conditions of Uranium Mineralization of Zoujiashan Deposit in Xiangshan Orefield

Abstract: This paper is mainly on the fluid inclusions of uranium ores form Zoujianshan deposit in Xiangshang uranium ore-fieldTest result of fluid inclusions shew that the homogenization temperature distributed in a wide range from 122 ℃to 360 ℃ and can be divided into two phasesThe high temperature phase was from 213 to 360℃ with the average of 2631℃and low temperature phase was from 122 to 185℃ with the average of 1427℃,which suggest that the deposit falls into median-low temperature hydrothermal depositsIn high temperature phase,the salinity of inclusion was(174~731)wt% with the average value of 377wt%,and in low temperature phase the salinity ranged from 088wt% to 257wt% with the average of 164wt%In high temperature phase,the mineralization solution was with the average density of 078g/cm3 and the pressure of 20457×105Pa which refer to the depth of 068kmIn low temperature phase the mineralization solution was with the average density of 092g/cm3 and pressure of 9608×105Pa which refer to the depth 032kmBy summarizing the above information,we can inferred that the ore forming fluid is the main from post-magmatic hydrothermal fluid which was accompanied by atmospheric water

Progress and Outlook of Uranium Exploration in Meso-Cenozoic Basins in North China

Abstract: Through the efforts in last decades on the research of geology setting and regional assessmen for uranium exploration in the Meso-Cenozoic basins in North China,rich accomplishment have been gotten in metallogenic theory,temporal and spatial distribution pattern,zone division,Classification,mineralization of different type,ore-controlling factors,metallogenic model,principle of evaluation and prognostication,exploration criteria and great breakthrough in the prospecting of key areas.However,the extensive territory make the effort limited only to some region,the exploration level is fairly lower in the whole country,and there is wide space for uranium exploration.The further exploration should be basically guided by "highlighting the exploration of key areas,strengthening the evaluation of regional potential and accelerating the implementation of new reserve bases " and persisted in principle of "deployment with different level and execution according to region " and oriented with different types of deposit by "wholly evaluation and systematic exploration".By deploying the new effort frame in large base exploration,regional evaluation and solving the important geological and geophysical problem,we can put forward the uranium exploration in Meso-Cenozoic basins in North China.

Discussion on the Genesis of Baixintu Uranium Deposit in Sonliao Basin

Abstract: Baixintu uranium deposit is with the following major features:(1) well developed low temperature hydrothermal alteration of kaolinization,carbonation,pyritization,hydromicazation,sericitization,hematization et al,and uranium mineral coexisted with hydrothermal pyrite and ankerite and hematite in colloid,mass,strawberry;(2) vein orebody with coffinite as main mineral and a little pitchblende and titanium;(3) complicated isotopes feature of Carbon(δ13C is-268‰～-1049‰),oxygen(δ18O is-1074‰～-171‰),sulfur(δ34S is 1224‰～1433‰ and-3306‰) which are related to atmosphere water,magma,biological transformation and the dissolution of carbonate and sulfateThe above feature shew obvious oxidization and hydrothermal action,and the synthesyzed results of shallow-oxidization and deep fluid actionIn other word,the deposit has "double-open metallogenic system" characteristics of infiltration-type and exudation-type

Characteristics and Genesis of Porphyroclastic Lava Rock in Xiangshan

Abstract: Due to the transitional characteristics of porphyroclastic lava rock in Xiangshan of Jiangxi province,there are a variety of views on its genesis,petrographic attribution.This is because the marginal facies of the porphyroclastic lava is with ignimbrite and tuff characteristics,its transition phase has the characteristics of lava,and its intermediate phase has the feature of sub-volcanic rocks,further more,different texture of the rocks bears transition relationship.By the study of mineral composition,REE pattern,trace elements,isotopes,we put forward that the porphyroclastic lava is formed by the remelting of basement metamorphic rocks.The rocks was believed to be formed in the environment similar to volcanics and subvolcanics,and quite different to plutonic rocks due to the features of low-structure of potassium feldspar phenocrysts and solution mechanism,because the porphyroclastic lava phenocrysts occurs as fragments and maybe related to cryptoexplosion.Therefore the rocks was believed to belong to the volcano extrusive facies.

The Geochemical Characteristics of Alkali Metasomatic Ore and Its Ore-Forming Significance at Zoujiashan Deposit, Xiangshan Uranium Field

Abstract: Alkaline metasomatites are widely distributed in Zoujiashan uranium deposit and have close relation with uranium mineralization.Based on the study of field geological survey,petrographic methods,element chemical analysis and EPMA,etc,the alteration in alkaline metasomatic ore was found in the order of sodium metasomatism,potassium metasomatism and silica metasomatism.The alkaline hydrothermal fluid of mineralization is rich in Na at first and then rich in K,and quite similar in orther chemical composition,but the K rich one is more favourite for the metalization.Compared with the normal porphyroclastic lava,the alkaline metasomatic ores in lower in SiO2,but higher in K2O or Na2O,Al2O3,Fe2O3,MgO,P2O5,CaO and U,Th,Zr,Hf,Sm,Ti,REE.Compared with potassium metasomatic ore,the sodium metasomatic ore is with high ΣLREE/ΣHREE ratio and lower Rb and REE.Because alkaline metasomatism is beneficial to release uranium from accessory mineral and bring out uranium from rocks,therefore it is very important to the migration and precipitation of uranium.

Magma-Dynamical Evidence for Indo-Sinian Emplacement of the Uranium-Bearing Jinjiling Granite Batholith and its Tectonic Implication

Abstract: From the geological-geochemical features of Jinjiling granite batholith,the depth of emplacement(7.5 km),the temperature of country rocks(270 ℃)and the initial temperature of the melt(950 ℃)during it emplacement are obtained.With these parameters a mathematic calculating model for the emplacement age of Jinjiling granite batholith is established in this paper.Model calculation results suggest that the cooling period(Δtcol)for Jinjiling granite batholith from its initial temperature to crystallization temperature(600 ℃)was 3.91Ma,the prolongation period(ΔtL)caused by latent heat generated from crystallization was 2.92 Ma.Since the radioactive elements of Jinjiling granite batholith(U—16.5×10-6,Th—51.3×10-6,K2O—4.82%)are as high as 3 times of the average of the world granites(U—5×10-6,Th—20×10-6,K2O—2.66%),the prolongation period(ΔtA)caused by radiogenic heat from the decay of these radioactive elements is 34.5 Ma which is much longer than the ΔtA value calculated for the world granites average(2.82 Ma).Therefore,the time elapsed from the emplacement to the end of crystallization(ΔtECTD)should be the sum of Δtcol,ΔtL,and ΔtA,which was 41.3 Ma for Jinjiling granite batholith.In combination with zircon U-Pb age of the granite(156 Ma)which represents the crystallization age,the emplacement age of Jinjiling granite batholith(tE)is estimated to be 197.3 Ma.This suggests that the emplacement of Jinjiling granite melt was in the Indo-Sinian Period.

Character of Chlorite and Its Relationship to Uranium Mineralization in Uranium Deposit No.302

Abstract: Based on the EPMA analysis and mineralogy study,the chlorites in uranium deposit No.302 are classified into 4 types which have 4 occurrences respectively.The forming condition and tempretures of chlorites were discussed and used to deduce the forming condition of uranium forming environment.The forming process of uranium mineralization was believed to experience different tempreture at different stage.In pro-mineralization stage,the hydrothermal solution was of high tempreture and first resulted in the chlorization of biotite,and then the metasomatism of feldspar to form chlorite of feldspar alteration type and fissure filling type.In mineralization stage,the hydrothermal solution was of low tempreture and form disseminated chlorite.

Analysis of the Impedance Estimation Process of EH4

Abstract: The key steps and performance in the data process of STRAGEM(EH4)system was discussed in details,especially the raw cross-powers caused by the time-serial data's FFT,its stack and the corresponding problems in the X file(the cross-power file)such as frequency reflecting,attribution and sifting,as well as those between X file and Z file(impedance file)The solution to the above problems can provide a basis for the related researcher to develop new impedance estimation technique for the EH4's time-serial data

Metallogenic Condition of Granite Type Uranium Deposit and its Potential in Southern Jiangxi Province

Abstract: Southern Jiangxi is an important uranium-producing base of granite type in China.The features of uranium-producing granites and metallogenic condition of granite type uranium deposits was analysed and studied according to deep-source and multi-phase metallogenetic theory.The metallogenic model for granite type uranium deposit in southern Jiangxi was summarize and the prospecting criteria were proposed as marginal,alteration,fault and hydrothermal solution.Four uranium potential target areas were delineated.