Cretaceous system stratigraphic division method for ultra-thick uranium-producing target stratum

The invention discloses a cretaceous system stratigraphic division method for an ultra-thick uranium-producing target stratum, and relates to the technical field of uranium mine geological exploration, and the method comprises the following steps: collecting and sorting data of construction, deposition, magmatic rock, geophysics, geochemistry and paleoclimate, and carrying out comprehensive analysis; determining a construction-deposition-evolution sequence, and further determining deposition features and transformation features; cretaceous sedimentary evolution and construction and magmatic activity are determined, and then cretaceous system stratum top and bottom interfaces and layer group units are determined; identifying division marks of each layer group unit of the cretaceous system stratum, wherein the division marks comprise geodetic structure, sedimentology, geophysics and paleoclimate; stratigraphic comparison is carried out, large and medium and small scale comprehensive profiles in each layer group