Geological Features and Formation Processes of the M akeng F e Deposit, C hina

Recent studies have revealed that the M akeng F e deposit is a skarn type deposit. However, the skarns in M akeng, occurring primarily between limestone and sandstone, are not typically associated with limestone and plutons. Different periods of intrusions, e.7. H ercynian mafic intrusions and Y anshanian (i.e. early C retaceous) D ayang– J uzhou granitic intrusion, occurred in the M akeng deposit district. In this study, the formation processes of the skarns and F e mineralization are constrained by detailed fieldwork, petrology, geochronology, and geochemistry. Skarns and F e mineralization intersecting the H ercynian mafic intrusions are observed in consecutive specimens from the 106# tunnel. They suggest that the skarn formation and F e mineralization occurred after the H ercynian mafic intrusions and are related to the later Y anshanian D ayang– J uzhou granitic intrusion. The geochronological characteristics of weakly skarn‐altered diabases, the decreasing nature of F e contents in altered diabase, and the major element compositions of pyroxenes and garnets also support that H ercynian mafic intrusions are strongly reformed by Y anshanian granitic magmas and the F e migrated from mafic intrusion was responsible for formation of iron ore.