Research On Metallogenic Characteristics And Ore-controlling Factors Of Mengqiguer Uranium Deposit

Apply the theory of sandstone-type uranium mineralization of interlayer oxidation zone as a guidecombined with analytic technique such as chemical analysis, scanning electron microscope, X-raydiffraction, electron probe method in order to systematically analyse Mengqiguer uranium metallogeniccharacteristics and thickness of sand body, the interlayer oxidation zone, tectonics on the southernmargin of the Yili basin. Achievements are following:1. The uranium ore body is snakelike, which is controled by the interlayer oxidation zone shape.Rich region projection is located in the center of the ore-body and The interlayer oxidation zone oflateral pinchout line.Lean ores enwaping rich regions display the characteristics of superimposedenrichment.Mengqiguer uranium minerals are pitchblende and coffinite. Sample P1316-1elements back scatterdiagram shows bright asphalt uranium mineral inclusions slightly dark pitchblende.82.488%UO2content of the former is lower than91.046%of the latter, shows the existence of two uraniummineralization periods, and ore-forming process has the characteristics of superimposed enrichment.2. The majority metallogenic age concentrated in the12.1Ma. Mengqiguer uranium metallogenicperiod is divided into four periods: preconcentration stage of early-Middle Jurassic diagenetic;supergene epigenetic mineralization stage of the late Early Cretaceous to early Oligocene; the middleMiocene-Pliocene epoch (12.1~2Ma) as the main metallogenic stage deposits; superpositionreconstructiothe after the late Pliocene (2Ma).3. The thickness of Ⅴ1sand body in the uranium deposit is greater than5m, the ore-body islocated in the sand body larger than7.5m region; The thickness of Ⅴ21sand body is greater than6m,the ore-body is located in the sand body larger than6m region; The thickness of Ⅴ22sand body isgreater than10m, the ore-body is located in the sand body larger than15m region. Sand body thicknesshas a certain influence on the development of interlayer oxidation zone, and affect the development ofinterlayer oxidation zone width and oxidation front line shape.4. The interlayer oxidation with the following characteristics:Ⅴ1,Ⅴ21,Ⅴ22cycle interlayer oxidation zone is serpentine, zonal distribution, and is imbricatedistribution in the profile. By the effect of thestructural supply window of central F1fracture, interlayeroxidation zone is NW protrusion. Through the research of Fe3+/Fe2+, color, organic carbon content,the interlayer oxidation zone is divided into strong oxidation zone, moderate oxidation zone, weak oxidation, redox transitional zone and reduction zone..Reducing agents in the interlayer oxidation zone of Mengqiguer uranium deposit is mainly organiccarbon, pyrite, hydrocarbon, adsorbent is mainly organic carbon. The interlayer oxidation zone ofuranium content was positively associated with organic carbon contentClay minerals of Mengqiguer uranium deposit are kaolinite, illite and illite-smectite。 clay mineralcontent in the interlayer oxidation zone shows a certain regularity. The adsorption capacity of clayminerals for uranium is finite. High quality fraction of Clay mineral has an effect on sand permeability,which is not conducive to uranium mineralization.5. Tectonic movement and uranium metallogenic has regularity in the distribution of time。Eachtectonic movements are associated with uranium mineralization, and metallogenic process are basicallyin the intermittent of tectonic movement.According to the tectonic and mineralization, build the deposit metallogenic model.Find thicknessof sandstone is the uranium metallogenic foundation, interlayer oxidation zone chontrol uraniummineralization, organic carbon is reducing substance, tectonic activity is the driving factor.