This paper is the result of oil and gas exploration engineering.
[Objective]This paper takes Hangjinqi-Daying Uranium deposit as the research area, and we studied the carbonation type、 period and the characteristics of in-situ micro-zone carbon and oxygen isotopes, providing a new information and basis for the formation and cause of sandstone uranium deposits in this area. [Methods]By using the field observation, rock core collection of industrial hole in ore-bearing horizon, high power microscope observation, electron probe analysis, we distinguished the different stages of Carbonation(Mainly calcite). The C-O isotope test was carried out by using the SHRIMP stable isotope tracer technology, which provides a reasonable and more accurate way to tracing the formation process of sandstone uranium deposit.[Results]Both the mineralization period and post mineralization period of fluid have the source of genetic characteristics by using in-situ micro-area C-O isotopes testing method, and the oxygen isotope of calcite shows that the fluid has the characteristics of atmospheric water. it is believed that the natural gas moved to the north together with the groundwater forming the low- temperature hydrothermal fluid provided the carbon source. The "calcified wood"-like carbonated calcite in this area is mostly distributed along crystal caves or penetrated along cracks, and it is obviously the result of natural gas filling along the cracks in post mineralization period. Therefore, the natural gas- water mixed fluid effect can be extended to post mineralization period， which has the effect of superimposed enrichment and mineral preservation. [Conclusions]The application of electron probe, SHRIMP stable isotope tracing and other methods provide the core technical guarantee for in-situ micro-area stable isotope tracing, and provide an effective test method for the fine study of the characteristics of ore-forming fluids.