Discussion on uranium mineralization model in Miyi Pass-Haita area

Research on the characteristics of uranium mineralization in the Miyi Pass-Haita area is still preliminary. A lot of work is still in progress, and it is difficult to summarize a mature model. However, in order to start with the prospecting goal, we have initially sketched out a conceptual model of uranium prospecting and mineralization (Figure 6.5), striving to shed some light on uranium prospecting in the region.

The Miyi Pass-Haita area developed a magmatic rock series of basalt-alkaline syenite-granite (monzonite, potassium feldspar granite) in the late Hercynian-Indosinian period, which was produced in Pan The extensional tectonic environment of the West Paleorift Valley is controlled by the Xigeda Fault Zone. There are also a large number of gabbro, diabase veins, granite veins and felsic veins in the later period. They are controlled by regional fault zones and ductile shear zones. They develop after potassium feldspar granite and even form gneiss-like formations with granite. shape structure. This type of granite has slightly higher U and higher Th content. When the ductile structure continues to develop into brittleness, the felsic veins or light-colored granite veins filled in the structural belt will undergo fragmentation and deformation. The ductile-brittle structural zone connects deep magma source fluids and becomes an important channel for fluid activity. It activates uranium and other materials in the structure and surrounding rocks to form ore-bearing thermal fluids. The migration of ore-bearing fluids to the brittle stage provides good conditions. In the storage space, due to changes in physical and chemical conditions, uranium is reduced to form crystalline uranium ore, and molybdenite precipitates at the same time, forming single uranium-type mineralization and U-Mo type mineralization, as well as a small amount of copper mineralization and pyrite. (sulfur ore).

Uranium mineralization in the Yakou-Haita area is a medium (low) temperature hydrothermal mineralization related to magmatic activity and controlled by ductile-brittle structures. Therefore, it is very important to study the mineralization conditions (uranium sources, reducing substances, etc.) of granite and metamorphic rocks, the relationship between ductile-brittle structure and mineralization, and the composition of minerals in this area.

Figure 6.5 Sketch of conceptual model of uranium prospecting and mineralization in the Yiyakou-Haita area

1—Late Hercynian-Indosinian granite body (monzonitic granite, potash feldspar granite) and granite dikes; 2—Late Hercynian-Indosinian alkaline rock mass (syenite); 3—felsic vein body; 4—ductile shear zone; 5—possible migration of ore-bearing fluids direction. Xwm—Proterozoic Wumaqing Formation epimetamorphic rock series; U—uranium mineralization; U-Mo—uranium-molybdenum mineralization type