Abstract:
Abstract:Detailed field observations have revealed that the Damiao iron ore field obviously has excellent potential and is likely to become the largest base area of iron resources in China. New evidence supports neither the opinion that all the component igneous units in the Damiao anorthosite complex were evolutionary products of a unique primary magma nor the hypothesis that ore magma was responsible for the formation of the Damiao-type iron deposit. The anorthosite underwent at least two more times of deformation than the norite, suggesting that the norite was emplaced after the consolidation and cooling of the anorthosite. The generation of the Damiao-type iron deposit is closely related to the noritic magma. Nevertheless, the ore-forming materials were derived from the concurrently emplaced transmagmatic fluids instead of from the noritic magma differentiation. The degassing process of the ore magma-fluid mixed materials in the deep crust led to the concentration of the ore-forming materials in the norite and the differentiation characteristics of the mineral veins, i.e., the apatite was concentrated in the shallow place, while the titanomagnetite became rich in the deeper part. The main ore bodies are buried in the norite substrate beneath the anorthosite cover. Therefore, the Damiao iron ore field is a very promising area instead of a crisis mine.