The Middle And Lower Jurassic Sedimentary Characteristics And Its Influence On Sandstone Type Uranium Mineralization In The Eastern Of Junggar Basin

Junggar Basin is located in the northern of Xinjiang,which is the second largest sedimentary basin in Xinjiang. Uranium mineralization is located in the Tianshan uranium mineralization Province. Adjacent to the uranium concentration area of Central Asia. It has found a large number of large-medium sized and even oversize sandstone type uranium deposits in the surrounding basin.Junggar Basin has similar regional geological background with these uranium bearing basins, but it is still a difficult large basin which is still unsuccessfully done for many years. In order to achieve the breakthrough in prospecting sandstone type uranium deposits of the Junggar basin, Jurassic in the eastern of the Junggar Basin which has well exposed outcrops, drill logging data-rich, a large number of oxidation zone and uranium mineralization information is the research object in this report. Formation which in the metallogenic conditions of sandstone type uranium deposits "structure-formation-transformation" is the purpose, to solve favorable target facies, the existence and development regular of the sand body which in the exploration depth range. To discuss the mineralization conditions of sandstone type uranium deposits by the sedimentation. To point out the direction of the uranium prospecting for the East and even the whole of the Junggar basin.The paper has made the following results by detailedly studying on the formation of studing area, sedimentary, oxidation zone and the development of uranium mineralization: Sedimentary Evolution of Jurassic is multicycle, multistage and succession, Forming several different size sets "mud- sand- mud" structure in the vertical, in which three times larger lake transgression control the two large "mud-sand- mud structure,one is the middle of Badaowan Group(mud)- the upper of Badaowan Group and the lower of Sangonghe group(sand)- the upper of Sangonghe group(mud). the upper of Sangonghe group(mud)- the lower of Xishanyao group and Shishugou group(sand)- the upper of Shishugou group(mud).It has developed a number of small level rhythmic layering in large sand group,Forming a small "mud-sand- mud" structure. Deposited product of lake retrograded progradation- lake inlet retrogradation developed favorable lithofacies combination in vertical. It becomed the potential uranium metallogenic strata of sandstone type uranium deposits. Wucaiwan-Laojunmiao area has the characteristics which controls source and sand by the tectonic pattern of concave and uplifting phases. Provenance was from Kelameili mountain mainly. Converging to the depression area and forming a sand body accumulation area. Braided river and braided river delta are the main favorable facies belts for sandstone type uranium deposits in the study area,and oxidation belts are often developed in the large frame channel sand bodies of the braided river and braided river delta. The distribution of the sand body accumulation area and the interlayer oxidation zone has the space coupling property, It is considered that the inheritance of the ancient fluid determines this characteristic. To sum up, Braided river and braided river delta which formed by lake regression-transgression sedimentary in the primary reductive construction is the main favorable space for sandstone type uranium mineralization in the study area. The depression sand body accumulation area of Wucaiwan- Laojunmiao area are the mainly exploration area for sandstone type uranium mineralization in the study area.