Geochemical characteristics of ore-bearing diorite porphyrite of the Nihe iron ore deposit in Lujiang, Anhui Province

Porphyry-like type iron deposits are one important type of polymetallic deposits in the Middle-Lower Reaches of Yangtze River, and have genetic relationship with concealed diorite porphyrite. The geochemistry study of ore-bearing diorite porphyrite is of significance for investigating deposit genesis and deep exploration. This study carried out lithogeochemical analysis of the ore-bearing diorite porphyrite in conjunction with detailed observation of drilling cores. The ore-bearing diorite porphyrite of the Nihe iron deposit is characterized by high SiO₂, K and alkali, low TiO₂, relatively high in LILEs such as Sr, K, Rb, Th, Ce, and depleted in HSFEs such as Nb, Ta, Ti, Zr, Hf, suggesting that it belongs to shoshonitic rock. Based on the Sr-Nd isotopic features, it can be inferred that magmatic source region should be enriched mantle, and evolution process of the magma was affected jointly by assimilation and fractional crystallization.