The indicative significance of apatite in the Ganfang region for lithium mineralization

• Apatite U–Pb dating from stockscheider and pegmatite veins constrains the formation age of the Ganfang Li deposit. • Trace-element compositions of apatite reveal the relationship between hydrothermal alteration and Li mineralization. • A genetic model for Li mineralization in the Ganfang area is proposed based on apatite trace-element signatures. Granite-related Li-Nb-Ta deposits, characterized by extensive albitization within plutons, represent a novel lithium resource. The Ganfang area, one of the important granite-type lithium deposits in South China, features a vertical lithological sequence from top to bottom of stockscheider, albitized granite, and K-feldspar granite. The ore-bearing stratum is dominated by albitized granite. Our study focuses on elucidating the connection between magmatic differentiation, hydrothermal alteration, and lithium mineralization in albitized granites. By analyzing geochemical trends in apatite from stockscheiders, pegmatite veins, and altered granites, we aim to unravel the petrogenetic and metallogenic mechanisms of rare metal lithium. Apatite serves as a geochemical tracer, recording the intensity of fluid alteration processes and their impact on lithium enrichment. The U-Pb dating results (142.2–143.2 Ma and 128.8 Ma) of apatite from the stockscheiders and pegmatite vein show that mineralization in the Ganfang area occurred during the Late Yanshanian period and associated with the melting of the lower crust. Strontium (Sr), (La/Yb) N, and (La/Sm) N can indicate that mineralization in this area is closely associated with fluid activity. Our findings highlight distinct differences in trace element contents of apatite between upper ore-bearing albitized granite and lower barren K-feldspar granite, with specific trace element ratios (e.g., Ge-Ga, Ce/Pb-Th/U, ΣREE + Y-Mn/Fe, and Sr/Y-ΣLREE) serving as indicators of metallogenic potential. The ore-bearing albitized granite exhibits high concentrations of Ga and Ge, with a strong positive correlation between the two elements, this phenomenon may be related to the hydrothermal metasomatism of topaz. In addition, the ore-bearing granite exhibits relatively high Ce/Pb, light rare earth element (LREE), and total rare earth elements plus yttrium (ΣREE + Y) contents. This study indicates that lithium mineralization in the Ganfang area is closely linked to multistage fluid activity in a sealed-system, with a formation process involving the upward dissolution of Na and Li-rich fluids to form stockscheider, and followed by downward migration to replace fresh monzonite granites, forming ore-bearing albitized granite and barren K-feldspar granite.