| The Erlian Basin is located in the middle part of the Tianshan-Xingmeng orogenic belt.It is an extensional rifting basin formed on the base of the Haixi fold.It is an important coal,oil,uranium and polymetallic mineral producing area in China.The Hadatu area is located in the central and eastern part of the Wulanchabu depression of the Erlian Basin.It is a large sandstone-type uranium deposit discovered in recent years with superior mineralization potential.Based on the data interpretation of field outcrop,core observation and geophysics,combined with the current analysis and testing techniques such as microscopic observation,electron probe and scanning electron microscopy,the petrological characteristics,diagenesis and post-cavitation of the uranium deposits in the Hadatu area.Systematic analysis and summary of variable and thermal fluid transformation,uranium metallogenic conditions(uranium source,structure,paleoclimate and reducing agent)and metallogenic model.The characteristics of debris particles in the target layer,fluid alteration phenomena,and segmentation of diagenesis and ore-forming stages are studied,which lays a foundation for the metallogenic model of the resume research area.The results of microscopic identification show that the sandstone structure maturity and compositional maturity of the upper part of the Saihan Formation in the target layer of the Hadada uranium deposit are low,mainly for feldspar lithic sandstone,with less cuttings and roundness of crumb particles.Angular angle-sub-angular angle,general sorting.It indicates that the source of the sediment is near source.Judging from the evidence of vitrinite reflectance,rock mineralogy composition,paleotemperature and fluid properties,which represent the maturity of organic matter,diagenesis only changes to the stage of the diagenetic stage and then enters the epigenetic stage,and then experiences the thermal fluid.The superposition effect is to superimpose the uranium mineralization and re-enrich uranium.The fluid alteration in the study area develops,the limonite mineralization develops in the oxidation zone,the chlorite and petrochemical are rare,and the clay is strengthened in the weak oxidation zone.The content is about 8.5%.Kaolin petrochemical,montmorillonite and Yili petrochemicals begin to appear;In-band clay is strong,the content is about 25%,mainly for Yili petrochemical,sericitization,visible chlorite,Imon mixed layer,yellow iron mineralization and organic matter appear in large quantities,rare partial carbonation;reduction zone The inner clay mineral is about 10%,the organic matter and pyrite mineralization account for a decrease in the comparative transition zone,the immon mixed layer is reduced,and the illite content is more.Judging from the combination characteristics of altered minerals,the fluid properties also experienced alternating evolution of weak base-weak acid-wet base in time and space.Electron probe research shows that uranium exists mainly in the form of independent uranium minerals and adsorbed uranium.The independent uranium minerals are asphalt uranium and uranium,and uranium minerals are closely associated with pyrite and charcoal.The comprehensive study shows that the uranium deposits in hadatu area are two stages of early metallogenic stage and the mineralization of submerge-interlayer oxidation zone,forming early tabular uranium bodies.The late stage mineralization is further enriched by deep thermal fluid superposition,and this two-stage mineralization model is obviously different from the saihan gaobi uranium deposit in the wulanqab depression and the cbayan ullah uranium deposit in the manite sag. |
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