| This dissertation is funded by the National Natural Science Foundation of China,which named “Vertical Zoning Characteristics in Zoige carbonaceous-siliceous-argillitic rock type uranium deposit”(No.41072064), and chooses the510-1uraniumdeposit for its high grade, large scale and representative significance to study. In thedissertation, on the basis of previous researchers, research is mainly focused on thevertical zoning characteristics in Zoige510-1uranium deposit, including macrogeological survey in field, vertical zoning characteristics of mineral association,vertical zoning characteristics of trace element in uranium ores or mineralized rocks,vertical zoning characteristics of trace element in gangue minerals which is closelyassociated with mineralization. Thus the vertical zoning characteristics in Zoigeuranium ore field has been summarized fully and systematically from a microscopicand macroscopic view, and an important geochemical interface of the510-1uraniumdeposit has been revealed. The achievements and views are as follows:1. Through detailed geologic observation in field and mineral compositionidentification under the polished sections and thin sections in door, the510-1carbonaceous-siliceous-argillitic rock type uranium deposit can be divided into theupper ore zone, middle ore zone and bottom ore zone, The mineral association,structure and texture of ores in each of the three ore zones are different with eachother.2. The studies on the composition characteristics of trace element in ores ormineralized rocks in510-1uranium deposit show that:(1) Compared with thecontinental crust element abundance, the trace elements in ores or mineralized rocks which is rich signally is Cd、Zn、U、Re、Mo、Sb、Tl、Bi, etc. Especially, theconcentration coefficient (K value) of U is as high as more than2000.(2)510-1uranium deposit is a polymetallic deposit which mainly comprises with U and isassociated with Zn、Ni、Mo、Co、V, etc.3. The studies on the correlation of trace element in ores or mineralized rocks in510-1uranium deposit show that:(1) U and Pb、Zr、Hf、Sb、W、Sc shows significantlypositive correlation in the ores or mineralized rocks, the correlation coefficientbetween them is0.54～0.92.(2) Between U and its associated elements in the ores ormineralized rocks shows no significant correlation, the correlation coefficient is0.06～0.36.4. The studies on the vertical zoning characteristics of trace element in ores ormineralized rocks in510-1uranium deposit show that:(1) The enrichment zone of U、Pb、Zr、Hf、Sb、W、Sc and REE in level No.5illustrates that there is an importantgeochemical interface nearby the No.5level of the510-1uranium deposit as well as ahigh concentration position of multi-metal for outburst of mineralization.(2) The510-1uranium deposit formed from deep to shallow is corresponding to theenvironment changed from the relative reduction to relative oxidation condition. Thesignificant changes of δCe and δEu nearby the No.5level of the510-1uraniumdeposit indicates a geochemical interface of oxidative-reductive condition existingnearby the No.5level.(3) Without obvious rules to follow in vertical zoningcharacteristics of U and its associated elements suggests that the associated elements(Zn、Ni、Mo、Co、V) and U have different metallogenic material source and formationmechanism.5. The studies on the correlation of trace element in calcite veins which areformed in metallogenic period in510-1uranium deposit show that:(1) U and Tl、Sbshows significantly positive correlation in calcite veins which are formed inmetallogenic period, the correlation coefficient between them is0.41and0.66respectively.6. The studies on the vertical zoning characteristics of trace element in calciteveins which are formed in metallogenic period in510-1uranium deposit show that:(1)The deposit formed from the No.7level to the No.5level is corresponding to thecontent of the three trace element (U、Sb、Tl) in calcite veins which are formed inmetallogenic period from high to low. There is a obvious valley value nearby the No.5level. The research indicates that because of ore-forming fluid mineralizes suddenlynearby No.5level of510-1uranium deposit, as a result of ore-forming elements in the fluid is reduced significantly, the content of ore-forming elements in calcite veins bycondensing crystallization is decreased obviously.(2) The content of the REE incalcite veins which are formed in metallogenic period is stable relatively from theNo.7level to the No.5level of the deposit. Then the deposit formed to shallow, thecontent of the REE in calcite veins which are formed in metallogenic period isreduced gradually. There is a obvious inflection point nearby the No.5level. Theresearch indicates that because of ore-forming fluid mineralizes suddenly nearby No.5level of510-1uranium deposit, as a result of REE in the fluid is reduced significantly,the content of REE in calcite veins by condensing crystallization is decreasedobviously.(3) The510-1uranium deposit formed from deep to shallow iscorresponding to the environment changed from the relative reduction to relativeoxidation condition. The significant changes of δCe and δEu in calcite veins whichare formed in metallogenic period nearby the No.5level of the510-1uranium depositindicates also a geochemical interface of oxidative-reductive condition existingnearby the No.5level.Detailed research on this deposit found the rules of vertical zonation in mineralassociation, structure and texture of ores, trace elements and rare earth elements, etc.The research indicates that there exists a high concentration position for trace and rareearth elements, which is also a mutational transition zone of oxidation-deoxidationand an “acid and alkali isolation” geochemical interface nearby No.5level of510-1uranium deposit (320m or so below the current surface mineralized outcrop). Theimportant geochemical interface in Zoige region will play a very important guidingsignificance in prospecting exploration. |
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