Abstract: | Daqiaowu uranium deposit oaurs in the contact Zone of quartz porphyry massif and explosive breccia chimney in the Mesozoic Mengshan caldera, belonging to porphyry type. Uranium oreforming has relations with "two-layer structure"of the porphyry massif, that is, ore-forming model of "two -layer structure". The shallow quartz porphyry is ore-bearing massif and the deep granite porphyry is ore-origimating one. Most mineralizations belong to fracture and breccia typer, and occur as little veined and disseminated. The shape of the ore-body is mainly vein-like, and the boundary of ore-body isn' t clear with country rocks, The material of rock - forming comes from uranium - rich calc - alkaline magma from deep in the crust or the mantle, and the material of ore -foming comes mainlg from hydrothermal solution and fluid after maginatic stage. uranium ore-forming process is that the uranium - rich hyolrothermal solution or fluid rise move explose and absorb from country rocks resulting in diagenetic mineralizafion in the contact zone of quariz porphyry massif in the shallow during uranium - rich granite magmafic crysfallizafion - differenfiafion in the deep. Eary stage is u - red iron froth,foming uranium - poor mineratization, and the late is u - polymetallic sulfide mineralization, forming uranium - rich mineralization, and the two stages of mineralizations superimpose to enrich. |