Rock magnetic investigation and its geological significance for vein-type uranium deposits in southern China

To characterize the metallogenic environment of a typical vein-type uranium deposit, samples from diabase dykes, alteration zones including metamorphic diabase and uranium ore, and granites were systematically investigated for six boreholes from southeastern China. Rock magnetic results indicate that coarse-grained magnetites (pseudosingle domain, PSD, and multidomain, MD) are dominant magnetic carriers in diabase. In contrast, the uranium ore is dominated by fine-grained magnetites (superparamagnetic, SP, and single-domain, SD). The concentration of magnetic particles in fresh granites is low. Magnetic properties of metamorphic diabases exhibit much greater variability of magnetic properties and higher degrees of sulfuration than unaltered diabase and granite, due to contact metasomatism and reduction effects close to the vein. Compared with diabase, magnetic remanence of the uranium ore is much lower, but displays much higher stability. The Koenigsberger ratio Q peaks in the uranium ore with a value of similar to 1.00. Using the systematic rock magnetic results to constrain the interpretation, the contribution of the intersection zone of diabase dyke and silicified fault to magnetic anomalies was further modeled, and the effects of the ore body are significant for magnetic exploration. Overall, rock magnetic investigations of vein-type uranium deposit provide a better understanding of the interactions between different rock types, and further facilitate regional magnetic surveys on the ground.