The Characteristics of Geochemistry and Alteration of the Jiling Uranium Deposit in the Longshou Mountains, Gausu Province: A Case Study from Drill ZKJ29-3

The Jiling Na-metasomatic uranium deposit is one of the most important deposits in the Longshou mountains ore belt, which is a key to the research on uranium mineralization in this area. Based on the logging data, microscope analysis, electronic probe and geochemical characteristics, we divide hydrothermal process into 5 stages including premetallogenic, early metallogenic, main metallogenic, post-metallogenic and after metallogenic stage. The alteration zones can be divided into zone A to zone F from the ore center to the alteration outer, and their geochemical characteristics are as follows:Na₂O and U contents decreasing distinctly from zone A to zone F; SiO₂ and Rb contents show a relieved "U" type; FeO and MgO contents show bimodal in zone A and zone E, while P₂O₅and HREEs contents are relatively higher in zone A and Zone D; TiO₂, Fe₂O₃, CaO, MnO, CO₂, Zr, V, Cs and REEs contents are distinctly higher in zones B, C and D. The ore forming hydrothermal solution is rebalanced magma water, which is rich in Na⁺, U⁶⁺ and CO₃^2-. Pitchblende was downloaded from hydrothermal solution by fluid boiling for pressure releasing suddenly, and the changing of pH and Eh promoted the conversion from U⁶⁺ to U⁴⁺. It could be hoped for a large scale uranium base are to be found under the guidance of altered mineral assemblages diagram in deep prospecting and ore forecasting.