Petrogenesis, Tectonics, and Metallogenic Potential of Early Paleozoic S‐type Granites in Pinghe, Southwestern Yunnan, China

Abstract A systematic study of early Paleozoic S‐type granites in Pinghe enhances our understanding of the tectonic evolution of proto‐Tethys and provides a foundation for exploring rare metal deposits in the region. The Pinghe granites consist of monzogranite and leucogranite. Zircon U‐Pb dating shows that the emplacement ages of the monzogranite and leucogranite are 502.0 Ma and 500.9 Ma, respectively. All samples have high SiO 2 content and a weakly to strongly peraluminous character (A/CNK = 1.08–1.23), consistent with S‐type granites. The monzogranite has relatively high CaO, Sr, Ba, and CaO/Na 2 O ratios but lower Rb. In contrast, the leucogranite has lower CaO, Sr, Ba, and CaO/Na 2 O ratios but higher Rb. The similar ε Nd ( t ) values (–9.3 to –8.4) and Pb isotopic compositions (( 206 Pb/ 204 Pb) t = 18.03–19.36, ( 207 Pb/ 204 Pb) t = 15.66–15.76, ( 208 Pb/ 204 Pb) t = 37.97–38.55) suggest that the monzogranite formed through partial melting of crustal greywacke, while the leucogranite originated from partial melting of crustal pelite. Regional geological studies suggest that these S‐type granites in Pinghe were emplaced in an active continental margin setting, associated with the westward subduction of the proto‐Tethys oceanic slab. The geochemical characteristics of leucogranite are consistent with those of tungsten‐tin‐related granites, indicating significant metallogenic potential for W and Sn deposits.