Whole Rock, Mineral Chemistry during Skarn Mineralization-Case Study from Tongshan Cu-Mo Skarn Profile

Studying the activation, migration and precipitation processes of ore-forming elements is essential for understanding genesis mechanisms skarn deposits. A typical profile formed by intrusion Yanshanian granodiorite into Carboniferous carbonate strata was studied. The highly consistent with classic profile, ranging from intrusion, weak alteration belt, belt (inner outer belt) mineralization (mainly characterized Cu mineralization) to surrounding marble without being affected late-stage low-temperature or supergene weathering alteration. Whole-rock data show that major trace exhibit relatively small changes in inner skarn, but huge variation boundary between skarn; Na, Al, Ti Sr significant decreases, while Fe, Mg, Zn, V Ni increases. elemental content 10–100 times more higher than marble, such as Ca, Cs diluted marble. During process some (such K, Rb Ba) were depleted inner, not enriched outer, indicating they may migrate farther locations. Grossularite developed light rare earth element (LREE) depletion heavy REE enrichment, well positive negative anomalies Eu (δEu = 0.42–3.95). Andradite zonation development, a anomaly 0.36–46.83). Some appear at edges garnets fluctuations fO2 during late process. correlation Fe3+ REE3+ Al3+ indicated there are different YAG substitution skarn. Low garnet contents variable Y/Ho ratios suggest REEs be primarily controlled water-rock interactions. Considering whole-rock contents, features garnet, we found elements, Ti, Zr Nb differences These characteristics can used distinguish rock body skarnification