Re-discussion on the temporal relation between uranium mineralization and red bed basin——Taking Lujing uranium ore field in the Hunan—Jiangxi border as an example
Lujing uranium ore field is one of the most important hard rock-hosted uranium ore fields in South China.The uranium deposits in the field are distributed around Fengzhou Basin.In this paper,a study on the correlation between the uranium ore belt and the red-bed cap rock in the Fengzhou Basin has been carried out,taking into account the uplift and denudation history of the Lujing ore field and the characteristics of the faults in the northern margin of the Nanxiong basin,it is considered that the Fengzhou basin is a remnant of the late Cretaceous—Paleogene red-bed basin and is a small part of a much larger(at least 5～10 times)red-bed basin,about 1.5～2.5 km of red layer sediments have been eroded.There is no necessary genetic relationship between uranium mineralization and red bed basin.The hydrothermal uranium deposits occurred before the formation of the red-bed basin,and were exhumed to the surface(about 95～75 Ma)and then covered by the red-bed basin,it was buried to the deepest depth(about 1.5～2.5 km)at 65～55 Ma.It began to rise again and exfoliation from 55～45 Ma,and is near the surface at about 40 Ma and stable in the normal temperature of the surface since then.The NW side of the Suichuan fault began to uplift and exfoliate rapidly in the middle Miocene about 15 Ma,and the uplift range of the NW plate is larger than that of the SE plate,which reflects the left-lateral strike-slip characteristics of the Suichuan fault,the superimposed zone of the fault and the Reshui fault can preserve the existing Fengzhou basin by pulling apart the basin to slow the uplift and exhumation.The Fengzhou basin plays an important role in the preservation of uranium deposits formed before the basin sedimentation.Therefore,in addition to the surrounding area of Fengzhou basin,there is a favorable area for uranium exploration under the basin,which greatly expands the prospecting space of Lujing uranium ore field.
uranium mineralizationFengzhou basinuplift and denudation historyore-preserving structureprospecting directionLujing uranium ore field
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