Constraints of Mesozoic-Cenozoic tectonic-sedimentary evolution on uranium mineralization and prospecting prediction in the central and southern Bayin Gobi Basin

This paper is the result of mineral exploration engineering.

Objective The Mesozoic and Cenozoic Bayin Gobi basin mainly experienced Early Cretaceous fault depression, fault depression transition and Late Cretaceous depression development stages. The restriction of multi-stage structural transformation on uranium mineralization is not clear, which affects the next prospecting and prediction work.

Methods In this paper, the depression in the central and southern part of the basin is selected as the research area. Based on the previous achievements and the comparative study of geological sections, the influence of depression structural style and structural evolution on sedimentary filling is systematically studied.

Results During the Early Cretaceous, Middle and Late (109.7 ± 1.5) Ma -(115.5 ± 1.5) Ma, Late Cretaceous Paleogene (45.4 ± 0.6) Ma-(70.9 ± 1.0) Ma and Neogene (12.3 ± 0.2) Ma-(2.5 ± 0.0) Ma, on the one hand, the tectonic sedimentary evolution in the basin is conducive to the formation of denudation window, and then the development of large-scale interlayer oxidation and multi-stage epigenetic superposition which controls the development of ore-forming fluid and interlayer oxidation zone from the edge of the depression to the center of the depression, and forms uranium mineralization near the redox barrier; On the other hand, the groundwater in the south of the basin changes from runoff weak runoff to stagnant water, which is conducive to the decomposition, precipitation and enrichment of uranium in the ore-forming fluid under water-rock process.

Conclusions Under the favorable tectonic background, uranium mineralization in the central and southern Bayingobi basin is mainly controlled by sedimentary facies and interlayer oxidation zone.