Abstract: Although previous studies have been conducted in great detail on oceanic ferromanganese nodules, research on those nodules on seamounts in the marginal sea slope remains relatively insufficient. In this study, ferromanganese nodules were sampled from the Lichun Seamount in the northern slope of the South China Sea for research. Comprehensive analytical techniques were applied, including XRD mineralogy, LA-ICPMS in-situ major and trace element geochemistry, and layered isotope geochemistry, and the origination of the ferromanganese nodules was investigated. Results reveal that the ferromanganese nodules have four distinct layers with unique mineral compositions, reflecting different hydrodynamic conditions and terrigenous input rates during their growth. The nodules are mainly composed of vernadite, quartz, and plagioclase. However, in addition to vernadite, the manganese-phase minerals in layers 3 and 4 also contain birnessite and todorokite, suggesting their diagenetic origin. The results of principal component analysis indicate that the ferromanganese nodules are characterized by multi-stage and multi-source mineralization indicated by the formation of iron-phase minerals and the growth of manganese-phase minerals. The Mn/Fe ratio was less than 2.5 mostly, while at a few points in layers 3 and 4, it was above 2.5 or even exceeded 5. The REY partition pattern of the nodules displayed a strong positive Ce anomaly, and most of them were mirror-symmetric with the South China Sea seawater. The REY partition pattern at a few detection points in layers 3 and 4 were similar to that of the sediment pore water. The Sr-Nd isotope values were between the South China Sea seawater and sediment but closer to the seawater, and the Pb isotope exhibited the characteristics of Taiwan Island source. Therefore, the ferromanganese nodules were mainly of hydrogenetic origin, with a small number of diagenetic components added in the later growth stage. The materials were originated from the surrounding seawater and affected by terrigenous material input from Taiwan Island.