Geochemical Characteristics and Their Geological Significance of Zircon and Apatite From the Wunugetushan Porphyry Cu–Mo Deposit, Inner Mongolia, NE China

ABSTRACT The Wunugetushan (Wushan) porphyry Cu–Mo deposit is located in the southwestern segment of the Derbugan metallogenic belt. In this study, geochemical analyses of zircon and apatite from pre‐mineralization biotite granite (BG) and inter‐mineralization monzogranitic porphyry (MGP) were conducted, aiming to discuss petrogenesis and their constraints on mineralization. BG apatites have distinctly lower ε Nd ( t ) (−4.28 to −1.03) and higher two‐stage Nd model ages (1063–1328 Ma) than MGP apatites, showing values of −0.23 to +1.31 and 860–984 Ma. MGP zircons have higher Ce/Nd, Ce 4+ /Ce 3+ , δ Eu, 10,000 × δ Eu/Y and (Ce/Nd)/Y values, and lower Yb/Gd values than those in BG zircon. These geochemical features suggest that the MGP has a higher oxidation state and higher water content of magma than BG. Trace element concentrations in zircon and apatite reveal that the MGP is less evolved and exhibits amphibole‐dominated fractionation. In contrast, the BG is evolved and shows plagioclase‐ and apatite‐dominated fractionation. We propose that the key factors making the MGP fertile for mineralization, including its high Cl, S and H 2 O contents, high oxidation state, significant fluid exsolution and multiple recharges of deep‐seated mafic magma, were all critical for the Wushan porphyry Cu–Mo deposit.