Elements Migration in Tectonic-alteration Zones of the Xiadian Gold Deposit, Eastern Shandong Province and Its Relationship with Au Precipitation

The Xiadian gold deposit is occurred as one of typical gold deposits in Zhaoping Au mineralization belt, eastern Shandong province, which is associated with extensively altered rocks. According to the structure and content of altered minerals in altered host rocks, the tectonic-alteration zones in this deposit can be divided into six subzones, such as fault gouge, beresitization cataclasite, weak fragmented mylonite, fragmented beresitization granite, fragmented granite and fragmented syenogranite. Based on the analysis of altered minerals and Au contents, it's found that the gold ore of the Xiadian deposit were mainly hosted in the beresitization cataclasite sub-zone.After selecting the relative weak altered sample (X652-550-9) as the standard sample while the Y element as the element conservation, the relative migration rate of elements in the beresitization cataclasite sub-zone has been calculated.The results show that the migration rate of SiO₂, Al₂O₃, Na₂O and K₂O can be ignored, but LOI, MnO, P₂O₅, TiO₂ and MgO show a emigrate trend.The migration rate of Au is low at the area nearby the F1 fault, whereas migration rate of Au increase significantly near F2 fault, which show that the plagiogranite (protolith) was altered by ore-forming fluids along F1, causing element homogenization in the whole altered zone. Inthe beresitization cataclasite zone, the characteristics of element migration rate indicate that the host rocks were extensively modified by faults and altered by ore-forming fluids, which are consist with the occurrence of numerous gold deposits in Eastern Shandong Province.