Contrasting Geochemistry of Apatite from Triassic Li-Mineralized and Barren Pegmatites in the Ke'eryin Field, Eastern Tibetan Plateau.

This article focuses on the geochemical and isotopic study of apatite in Triassic pegmatites from the Ke'eryin field in the eastern Tibetan Plateau to understand the petrogenesis and lithium (Li) mineralization potential of these pegmatites. It finds that apatite from Li-mineralized dikes differs significantly from that in barren dikes in terms of trace elements, rare-earth element (REE) patterns, and isotopic compositions, reflecting distinct fractional crystallization trajectories of their parental melts. The melts forming mineralized pegmatites are more evolved, richer in Li, manganese (Mn), and thorium (Th), and have experienced a higher degree of fractional crystallization than those forming barren pegmatites. Nd isotopic data indicate that both mineralized and barren pegmatites likely originated from leucogranitic melts or anatectic melts of metasedimentary rocks with similar isotopic signatures. The study proposes that apatite grains with Li concentrations greater than 6 ppm can serve as reliable indicators of Li mineralization potential in limitedly exposed pegmatites, offering a valuable exploration tool in regions with sparse outcrops such as the Tibetan Plateau.